Title: The Hunting Wasps
Author: Fabre, Jean-Henri
Language: English
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                        THE WORKS OF J. H. FABRE

                                  THE
                             HUNTING WASPS


                                   BY
                             J. HENRI FABRE

                             Translated by
                  ALEXANDER TEIXEIRA DE MATTOS, F.Z.S.


                          HODDER AND STOUGHTON
                   LONDON      NEW YORK      TORONTO



TRANSLATOR’S NOTE


Henri Fabre’s essays on Wasps will fill three volumes in all, of which
this is the first. The others will be entitled The Mason-Wasps and More
Hunting Wasps. The former will include the chapters on the Common or
Social Wasp.

The first seventeen chapters of the present book appeared some years
ago, wholly or in part, in a version of vol. i. of the Souvenirs
Macmillan and Co., by arrangement with whom I am now permitted to
retranslate and republish them for the purpose of this collected and
definite edition of Fabre’s entomological works. Of the remainder, ‘The
Modern Theory of Instinct’ first saw the light in the English Review,
and ‘An Unknown Sense,’ in an abbreviated form, in the Daily Mail.

It is a pleasure once more to express my thanks to Miss Frances
Rodwell, who, as usual, has rendered me much valuable assistance, and
to Mr. Geoffrey Meade-Waldo, of the Natural History Museum, who has
been kind enough to set me right on many an entomological point.


    Alexander Teixeira de Mattos.

    Chelsea, 1916.



CONTENTS


                                                    PAGE

        TRANSLATOR’S NOTE                              V

        CHAPTER I
        THE BUPRESTIS-HUNTING CERCERIS                 1

        CHAPTER II
        THE GREAT CERCERIS                            18

        CHAPTER III
        A SCIENTIFIC SLAUGHTERER                      40

        CHAPTER IV
        THE YELLOW-WINGED SPHEX                       58

        CHAPTER V
        THE THREE DAGGER-THRUSTS                      75

        CHAPTER VI
        THE LARVA AND THE NYMPH                       86

        CHAPTER VII
        ADVANCED THEORIES                            107

        CHAPTER VIII
        THE LANGUEDOCIAN SPHEX                       129

        CHAPTER IX
        THE WISDOM OF INSTINCT                       149

        CHAPTER X
        THE IGNORANCE OF INSTINCT                    174

        CHAPTER XI
        AN ASCENT OF MONT VENTOUX                    196

        CHAPTER XII
        THE TRAVELLERS                               215

        CHAPTER XIII
        THE AMMOPHILÆ                                231

        CHAPTER XIV
        THE BEMBEX                                   251

        CHAPTER XV
        THE FLY-HUNT                                 271

        CHAPTER XVI
        A PARASITE OF THE BEMBEX. THE COCOON         284

        CHAPTER XVII
        THE RETURN TO THE NEST                       305

        CHAPTER XVIII
        THE HAIRY AMMOPHILA                          323

        CHAPTER XIX
        AN UNKNOWN SENSE                             341

        CHAPTER XX
        THE MODERN THEORY OF INSTINCT                354

        APPENDIX                                     379



CHAPTER I

THE BUPRESTIS-HUNTING CERCERIS


There are for each one of us, according to his turn of mind, certain
books that open up horizons hitherto undreamed of and mark an epoch in
our mental life. They fling wide the gates of a new world wherein our
intellectual powers are henceforth to be employed; they are the spark
which lights the fuel on a hearth doomed, without its aid, to remain
indefinitely bleak and cold. And it is often chance that places in our
hands those books which mark the beginning of a new era in the
evolution of our ideas. The most casual circumstances, a few lines that
happen somehow to come before our eyes, decide our future and plant us
in the appointed groove.

One winter evening, when the rest of the household was asleep, as I sat
reading beside a stove whose ashes were still warm, my book made me
forget for a while the cares of the morrow: those heavy cares of a poor
professor of physics who, after piling up diplomas and for a quarter of
a century performing services of uncontested merit, was receiving for
himself and his family a stipend of sixteen hundred francs, or less
than the wages of a groom in a decent establishment. Such was the
disgraceful parsimony of the day where education was concerned; such
was the edict of our government red-tape: I was an irregular, the
offspring of my solitary studies. And so I was forgetting the poverty
and anxieties of a professor’s life, amid my books, when I chanced to
turn over the pages of an entomological essay that had fallen into my
hands I forget how.

It was a monograph by the then father of entomology, the venerable
scientist Léon Dufour, [1] on the habits of a Wasp that hunted
Buprestis-beetles. Certainly, I had not waited till then to interest
myself in insects; from my early childhood I had delighted in Beetles,
Bees, and Butterflies; as far back as I can remember, I see myself in
ecstasy before the splendour of a Ground-beetle’s wing-cases or the
wings of Papilio machaon, the Swallowtail. The fire was laid; the spark
to kindle it was absent. Léon Dufour’s essay provided that spark.

New lights burst forth: I received a sort of mental revelation. So
there was more in science than the arranging of pretty Beetles in a
cork box and giving them names and classifying them; there was
something much finer: a close and loving study of insect life, the
examination of the structure and especially the faculties of each
species. I read of a magnificent instance of this, glowing with
excitement as I did so. Some time after, aided by those lucky
circumstances which he who seeks them eagerly is always able to find, I
myself published an entomological article, a supplement to Léon
Dufour’s. This first work of mine won honourable mention from the
Institute of France and was awarded a prize for experimental
physiology. But soon I received a far more welcome recompense, in the
shape of a most eulogistic and encouraging letter from the very man who
had inspired me. From his home in the Landes the revered master sent me
a warm expression of his enthusiasm and urged me to go on with my
studies. Even now, at that sacred recollection, my old eyes fill with
happy tears. O fair days of illusion, of faith in the future, where are
you now?

I am sure that my readers will welcome an extract from the essay that
formed the starting-point of my own researches, especially as this
extract is necessary for the due understanding of what follows. I will
therefore let the master speak for himself, abridging his words in
parts: [2]


    ‘In all insect history, I can think of no more curious, no more
    extraordinary fact than that which I am about to describe to you.
    It concerns a species of Cerceris who feeds her family on the most
    sumptuous species of the genus Buprestis. Allow me to make you
    share the vivid impressions which I owe to my study of this
    Hymenopteron’s habits.

    ‘In July 1839, a friend living in the country sent me two specimens
    of Buprestis bifasciata, an insect at that time new to my
    collection, informing me that a kind of Wasp that was carrying one
    of these pretty Beetles had let it fall on his coat and that, a few
    moments later, a similar Wasp had dropped another on the ground.

    ‘In July 1840, I was visiting my friend’s house professionally and
    reminded him of his capture of the year before and asked for
    details of the circumstances that accompanied it. The identity of
    the season and place made me hope to make a similar capture myself;
    but the weather that day was overcast and chilly; and therefore but
    few Wasps had ventured out. Nevertheless, we made a tour of
    inspection in the garden; and, seeing nothing coming, I thought of
    looking on the ground for the homes of Burrowing Hymenoptera.

    ‘My attention was attracted by a small heap of sand freshly thrown
    up and forming a sort of tiny mole-hill. On raking it, I saw that
    it masked the opening of a shaft running some way down. With a
    spade we carefully turned over the soil and soon saw the glittering
    wing-cases of the coveted Buprestis lying scattered around.
    Presently I discovered not only isolated and fragmentary
    wing-cases, but a whole Buprestis, then three or four of them,
    displaying their emerald and gold. I could not believe my eyes.

    ‘But this was only a prelude to the feast. In the chaos of rubbish
    produced by the exhumation, a Wasp appeared and fell into my hands:
    it was the kidnapper of the Buprestes, trying to escape from among
    her victims. In this burrowing insect I recognized an old
    acquaintance, a Cerceris whom I have found hundreds of times, both
    in Spain and round about Saint-Sever.

    ‘My ambition was far from satisfied. It was not enough for me to
    identify the kidnapper and her victim: I wanted the larva, the sole
    consumer of those rich provisions. After exhausting this first vein
    of Buprestes, I hastened to make fresh excavations and, planting my
    spade more carefully still, I at last succeeded in discovering two
    larvæ which crowned the good fortune of this campaign. In less than
    an hour I ransacked the haunts of three Cerceres; and my booty was
    some fifteen whole Buprestes, with fragments of a still larger
    number. I calculated, keeping, I believe, well within the mark,
    that this particular garden contained five-and-twenty nests, making
    an enormous total of buried Buprestes. What must it be, I thought,
    in places where in a few hours I have caught on the garlic-flowers
    as many as sixty Cerceres, whose nests were apparently in the
    neighbourhood and no doubt victualled just as abundantly? And so my
    imagination, never going beyond the bounds of probability, showed
    me underground, within a small radius, Buprestis fasciata by the
    thousand, whereas, during the thirty years and upwards that I have
    been studying the entomology of this district, I never discovered a
    single one in the open.

    ‘Once only, perhaps twenty years ago, I found the abdomen of this
    insect, together with its wing-cases, stuck in a hole in an old
    oak. This fact was illuminating. By informing me that the larva of
    Buprestis fasciata must live in the wood of the oak, it completely
    explained why this Beetle is so common in a district which has none
    but oak-forests. As Cerceris bupresticida is rare in the clay hills
    of such districts, as compared with the sandy plains thickly
    planted with the maritime pine, it became an interesting question
    to know whether this Wasp, when she inhabits the pine country,
    victuals her nest in the same way as in the oak country. I had a
    strong presumption that this was not the case; and you will soon
    see, not without surprise, what exquisite entomological
    discrimination our Cerceris displays in her choice of the numerous
    species of the genus Buprestis.

    ‘We will therefore hasten to the pine region to reap new delights.
    The field to be explored is the garden of a country-house standing
    amid forests of maritime pines. One soon recognized the dwellings
    of the Cerceris; they had been made solely in the main paths, where
    the firm, compact soil offered the Burrowing Hymenopteron a solid
    foundation for the construction of her subterranean abode. I
    inspected some twenty, I may say, by the sweat of my brow. It is a
    very laborious sort of undertaking, for the nests, and consequently
    the provisions, are not found at less than a foot below the
    surface. It becomes necessary, therefore, lest they should be
    damaged, to begin by inserting a grass-stalk, serving as a landmark
    and a guide, into the Cerceris’ gallery and next to invest the
    place with a square of trenches, some seven or eight inches from
    the orifice or the landmark. The sapping must be done with a
    garden-spade, so that the central clod can be completely detached
    on every side and raised in one piece, which we turn over on the
    ground and then break up carefully. This was the method that
    answered with me.

    ‘You would have shared our enthusiasm, my friend, at the sight of
    the beautiful specimens of Buprestes which this original method of
    treasure-hunting disclosed, one after the other, to our eager gaze.
    You should have heard our exclamations each time that the mine was
    turned upside down and new glories stood revealed, rendered more
    brilliant still by the blazing sun; or when we discovered, here,
    larvæ of all ages fastened to their prey, there, the cocoons of
    those larvæ all encrusted with copper, bronze, and emerald. I who
    had been studying insects at close quarters for three or four
    decades—alas!—had never witnessed such a lovely sight nor enjoyed
    so great a treat. It only needed your presence to double our
    delight. Our ever-increasing admiration was devoted by turns to
    those brilliant Beetles and to the marvellous discernment, the
    astonishing sagacity of the Cerceris who had buried and stored them
    away. Will you believe it, of more than four hundred Beetles [3]
    that we dug up, there was not one but belonged to the old genus
    Buprestis! Not even the very smallest mistake had been made by the
    wise Wasp. What can we not learn from this intelligent industry in
    so tiny an insect! What value would not Latreille [4] have set upon
    this Cerceris’ support of the natural method!

    ‘We will now pass to the different manœuvres of the Cerceris for
    establishing and victualling her nests. I have already said that
    she chooses ground with a firm, compact, and smooth surface; I will
    add that this ground must be dry and fully exposed to the sun. She
    reveals in this choice an intelligence, or, if you prefer, an
    instinct, which one might be tempted to consider the result of
    experience. Loose earth or a merely sandy soil would doubtless be
    much easier to dig; but then how is she to get an aperture that
    will remain open for goods to pass in and out, or a gallery whose
    walls will not constantly be liable to fall in, to lose their
    shape, to be blocked after a few days of rain? Her choice therefore
    is both sensible and nicely calculated.

    ‘Our Burrowing Wasp digs her gallery with her mandibles and her
    front tarsi, which are furnished for this purpose with stiff spikes
    that perform the office of rakes. The orifice must not only have
    the diameter of the miner’s body: it must also be able to admit a
    capture of large bulk. It is an instance of admirable foresight. As
    the Cerceris goes deeper into the earth, she casts out the rubbish:
    this forms the heap which I likened above to a tiny mole-hill. The
    gallery is not perpendicular, for then it would inevitably become
    blocked up, owing either to the wind or to other causes. Not far
    from where it starts, it forms an angle; its length is seven or
    eight inches. At the end of the passage the industrious mother
    establishes the cradles of her offspring. These consist of five
    separate cells, independent of one another, arranged in a
    semicircle and hollowed into the shape and nearly the size of an
    olive. Inside, they are polished and firm. Each of them is large
    enough to contain three Buprestes, which form the usual allowance
    for each larva. The mother lays an egg in the middle of the three
    victims and then stops up the gallery with earth, so that, when the
    victualling of the whole brood is finished, the cells no longer
    communicate with the outside.

    ‘Cerceris bupresticida must be a dexterous, daring, and skilful
    huntress. The cleanliness and freshness of the Buprestes whom she
    buries in her lair incline one to believe that she must seize these
    Beetles at the moment when they are leaving the wooden galleries in
    which their final metamorphosis has taken place. But what
    inconceivable instinct urges her, a creature that lives solely on
    the nectar of flowers, to procure, in the face of a thousand
    difficulties, animal food for carnivorous children which she will
    never see, and to take up her post on utterly dissimilar trees,
    which conceal deep down in their trunks the insects destined to
    become her prey? What yet more inconceivable entomological judgment
    lays down the strict law that she shall confine herself in the
    choice of her victims to a single generic group and capture
    specimens differing greatly among themselves in size, shape, and
    colour? For observe, my friend, how slight the resemblance is
    between Buprestis biguttata, with a long, slender body and a dark
    colour; B. octoguttata, oval-oblong, with great patches of a
    beautiful yellow on a blue or green ground; and B. micans, who is
    three or four times the size of B. biguttata and glitters with a
    metallic lustre of a fine golden green.

    ‘There is another very singular fact about the manœuvres of our
    Buprestis-slayer. The buried Buprestes, like those whom I have
    seized in the grasp of their kidnappers, are always deprived of any
    sign of life; in a word, they are decidedly dead. I was surprised
    to remark that, no matter when these corpses were dug up, they not
    only preserved all their freshness of colouring, but their legs,
    antennæ, palpi, and the membranes uniting the various parts of the
    body remained perfectly supple and flexible. There was no
    mutilation, no apparent wound to be seen. One might at first
    believe the reason, in the case of the buried ones, to be due to
    the coolness of the bowels of the earth, in the absence of air and
    light; and, in the case of those taken from the kidnappers, to the
    very recent date of their death. But please observe that, at the
    time of my explorations, after placing the numerous exhumed
    Buprestes in separate screws of paper, I often left them in their
    little bags for thirty-six hours before pinning them out. Well,
    notwithstanding the dryness of the air and the burning July heat, I
    always found the same flexibility in their joints. Nay more: I have
    dissected several of them, after that lapse of time, and their
    viscera were as perfectly preserved as if I had used my scalpel on
    the insects’ live entrails. Now long experience has taught me that,
    even in a Beetle of this size, when twelve hours have passed after
    death in summer, the internal organs become either dried up or
    putrefied, so that it is impossible to make sure of their form or
    structure. There is some special circumstance about the Buprestes
    killed by the Cerceres that saves them from desiccation and
    putrefaction for a week and perhaps two. But what is this
    circumstance?’


To explain this wonderful preservation of the tissues which makes of an
insect smitten for many weeks past with a corpse-like inertness a piece
of game which does not even go high and which, during the greatest heat
of summer, keeps as fresh as at the moment of its capture, the able
historian of the Buprestis-huntress surmises the presence of an
antiseptic fluid, acting similarly to the preparations used for
preserving anatomical specimens. This fluid, he suggests, can be
nothing but the poison of the Wasp, injected into the victim’s body. A
tiny drop of the venomous liquid accompanying the sting, the needle
destined for the inoculation, would therefore serve as a kind of brine
or pickle to preserve the meat on which the larva is to feed. But how
immensely superior to our own pickling processes is that of the Wasp!
We salt, or smoke, or tin foodstuffs which remain fit to eat, it is
true, but which are very far indeed from retaining the qualities which
they possessed when fresh. Tins of sardines soaked in oil, Dutch smoked
herrings, codfish reduced to hard slabs by salt and sun: which of these
can compare with the same fish supplied to the cook, so to speak, all
alive and kicking? In the case of flesh-meat, things are even worse.
Apart from salting and curing, we have nothing that can keep a piece of
meat fit for consumption for even a fairly short period.

Nowadays, after a thousand fruitless attempts in the most varied
directions, we equip special ships at great cost; and these ships,
fitted with a powerful refrigerating-plant, bring us the flesh of sheep
and oxen slaughtered in the South American pampas, frozen and preserved
from decomposition by the intense cold. How much more excellent is the
Cerceris’ method, so swift, so inexpensive, and so efficacious! What
lessons can we not learn from her transcendental chemistry! With an
imperceptible drop of her poison-fluid, she straightway renders her
prey incorruptible! Incorruptible, did I say? It is much more than
that! The game is brought to a condition which prevents desiccation,
leaves the joints supple, keeps all the organs, both internal and
external, in their pristine freshness, and, in short, places the
sacrificed insect in a state that differs from life only by its
corpse-like immobility.

This is the theory that satisfied Léon Dufour, as he contemplated the
incomprehensible marvel of those dead Buprestes proof against
corruption. A preserving-fluid, incomparably superior to aught that
human science can produce, explains the mystery. He, the master, the
ablest of them all, an expert in the niceties of anatomy; he who, with
magnifying-glass and scalpel, examined the whole entomological series,
leaving no nook or corner unexplored; he, in short, for whom insect
organism possessed no secrets can think of nothing better than an
antiseptic fluid to give at least the semblance of an explanation of a
fact that leaves him confounded. I crave permission to emphasize this
comparison between animal instinct and the reasoning power of the sage
in order the better to bring to light, in due season, the overwhelming
superiority of the former.

I will add but a few words to the history of the Buprestis-hunting
Cerceris. This Wasp, who is common in the Landes, as her historian
tells us, appears to be very rarely found in the department of
Vaucluse. I have met her only at long intervals, in autumn—and then
only isolated specimens—on the spiny heads of the field eryngo
(Eryngium campestre), in the neighbourhood either of Avignon or of
Orange and Carpentras. In this last spot, so favourable to the work of
the Burrowing Wasps owing to its sandy soil of Molasse formation, I
have had the good fortune, not to witness the exhumation of such
entomological treasures as Léon Dufour describes, but to find some old
nests which I attribute without hesitation to the Buprestis-huntress,
basing my opinion upon the shape of the cocoons, the nature of the
provisioning, and the presence of the Wasp in the neighbourhood. These
nests, dug in the heart of a very crumbly sandstone, known in the
district as safre, were crammed with remains of Beetles, remains easily
recognized and consisting of detached wing-cases, gutted corselets and
entire legs. Now these broken victuals of the larva’s banquet all
belonged to a single species; and that species was once more a
Buprestis, the Double-lined Buprestis (Sphenoptera geminata). [5] Thus
from the west to the east of France, from the department of the Landes
to that of Vaucluse, the Cerceris remains faithful to her favourite
prey; longitude makes no difference to her predilections; a huntress of
Buprestes among the maritime pines of the sand-dunes along the coast
remains a huntress of Buprestes among the olive-trees and evergreen
oaks of Provence. She changes the species according to place, climate,
and vegetation, which alter the nature of the insect population so
greatly; but she never departs from her favoured genus, the genus
Buprestis. What can her reason be? That is what I shall try to show.



CHAPTER II

THE GREAT CERCERIS


With my memory full of the prowess of the Buprestis-huntress, I watched
for an opportunity to observe in my turn the labours of the Cerceres;
and I watched to such good purpose that I ended by being successful.
True, the Wasp was not the one celebrated by Léon Dufour, with her
sumptuous victuals whose remains, when unearthed, suggest the dust of
some nugget broken by the gold-miner’s pick: it was a kindred species,
a gigantic brigand who contents herself with humbler prey; in short, it
was Cerceris tuberculata or C. major, the largest and most powerful of
the genus.

The last fortnight in September is the time when our Burrowing Wasp
digs her lairs and buries in their depths the victim destined for her
grubs. The site of the home, always selected with discrimination, is
subject to those mysterious laws which differ in different species but
are invariable throughout any one species. Léon Dufour’s Cerceris
requires a level, well-trodden, compact soil, such as that of a path,
to prevent the possibility of landslips and other damage which would
ruin her gallery at the first shower of rain. Ours, on the contrary, is
not very particular about the nature of her soil, but must have that
soil vertical. With this slight architectural modification, she avoids
most of the dangers that might threaten her gallery; and consequently
she digs her burrows indifferently in a loose and slightly clayey soil
and in the soft sand of the Molasse formation, which makes the work of
excavation much easier. The only indispensable condition appears to be
that the earth should be dry and exposed to the sun’s rays for the best
part of the day. It is therefore in the steep roadside banks, in the
sides of the ravines hollowed by the rains in the sandstone, that our
Wasp elects to establish her home. These conditions are common in the
neighbourhood of Carpentras, in the part known as the Hollow Road; and
it is here that I have observed Cerceris tuberculata in her largest
numbers and that I gathered most of my facts relating to her history.

The choice of this vertical site is not enough for her: other
precautions are taken to guard against the inevitable rains of the
season, which is already far advanced. If there be some bit of hard
sandstone projecting like a ledge, if there be naturally hollowed in
the ground some hole large enough to put one’s fist in, it will be
under that shelter or in this cavity that she contrives her gallery,
thus adding a natural vestibule to the edifice of her own construction.
Though no sort of communism exists among them, these insects
nevertheless like to associate in small numbers; and I have always
observed their nests in groups of about ten at least, with the
orifices, which are usually pretty far apart, sometimes close enough to
touch one another.

On a bright, sunny day it is wonderful to watch the different
operations of these industrious miners. Some patiently remove with
their mandibles a few bits of gravel from the bottom of the pit and
push the heavy mass outside; others, scraping the walls of the corridor
with the sharp rakes of their tarsi, collect a heap of rubbish which
they sweep out backwards and send streaming down the sides of the
slopes in a long thread of dust. It was these periodical billows of
sand discharged from the galleries in process of building that betrayed
the presence of my first Cerceres to me and enabled me to discover
their nests. Others, either because they are tired or because they have
finished their hard task, seem to rest and polish their antennæ and
wings under the natural eaves that most frequently protect their
dwelling; or else they remain motionless at the mouth of the hole,
merely showing their wide, square faces, striped black and yellow.
Others, lastly, flit gravely humming on the neighbouring
kermes-oak-bushes, where the males, always on the watch near the
burrows in course of construction, are not slow to join them. Couples
form, often disturbed by the arrival of a second male, who strives to
supplant the happy possessor. The humming becomes threatening, brawls
take place and often the two males roll in the dust until one of them
acknowledges the superiority of his rival. Near by, the female awaits
the outcome of the struggle with indifference; she finally accepts the
male whom the chances of the contest bestow upon her; and the couple
fly out of sight in search of peace and quiet on some distant
brushwood. Here the part played by the males ends. Only half the size
of the females and nearly as numerous, they prowl all around the
burrows, but never enter and never take part in the laborious mining
operations nor in the perhaps even more difficult hunting expeditions
by means of which the cells are to be stocked.

The galleries are ready in a few days, especially as those of the
previous year are employed with the aid of a few repairs. The other
Cerceres, so far as I know, have no fixed home, no family inheritance
handed down from generation to generation. A regular gipsy tribe, they
settle singly wherever the chances of their vagrant life may lead them,
provided that the soil suits them. But the Great Cerceris is faithful
to her household gods. The overhanging blade of sandstone that
sheltered her predecessors is adopted by her in her turn; she digs in
the same layer of sand wherein her forbears dug; and, adding her own
labours to those which went before, she obtains deep retreats that are
not always easy of inspection. The diameter of the galleries is wide
enough to admit a man’s thumb; and the insect moves about in them
readily, even when laden with the prey which we shall see it capture.
Their direction, at first horizontal to a depth of four to eight
inches, describes a sudden bend and dips more or less obliquely now to
this side, now to that. With the exception of the horizontal part and
the bend, the direction of the rest of the tube seems to be regulated
by the difficulties presented by the ground, as is proved by the twists
and turns observed in the more distant portion. The total length of the
shaft attains as much as eighteen inches. At the far end of the tube
are the cells, few in number and each provisioned with five or six
corpses of the Beetle order. But let us leave these building details
and come to facts more capable of exciting our admiration.

The victim which the Cerceris chooses whereon to feed her grubs is a
large-sized Weevil, Cleonus ophthalmicus. We see the kidnapper arrive
heavily laden, carrying her victim between her legs, body to body, head
to head, and plump down at some distance from her hole, to complete the
rest of the journey without the aid of her wings. The Wasp is now
dragging her prey in her mandibles up a vertical, or at least a very
steep surface, productive of frequent tumbles which send kidnapper and
kidnapped rolling helter-skelter to the bottom, but incapable of
discouraging the indefatigable mother, who, covered with dirt and dust,
ends by diving into the burrow with her booty, which she has not let go
for a single moment. Whereas the Cerceris finds it far from easy to
walk with such a burden, especially on ground of this character, it is
a different matter when she is flying, which she does with a vigour
that astonishes us when we consider that the sturdy little creature is
carrying a prize almost as large as herself and heavier. I had the
curiosity to compare the weight of the Cerceris and her victim: the
first turned the scale at 150 milligrammes; [6] the second averaged 250
milligrammes, [7] or nearly double.

These figures are eloquent of the powers of the huntress, nor did I
ever weary of admiring the nimbleness and ease with which she resumed
her flight, with the game between her legs, and rose to a height at
which I lost sight of her whenever, tracked too close by my
indiscretion, she resolved to flee in order to save her precious booty.
But she did not always fly away; and I would then succeed, not without
difficulty, lest I should hurt her, in making her drop her prey by
worrying her and rolling her over. I would then seize the Weevil; and
the Cerceris, thus despoiled, would hunt about here and there, enter
her lair for a moment and soon come out again to fly off on a fresh
chase. In less than ten minutes the skilled huntress had found a new
victim, performed the murder and accomplished the rape, which I often
allowed myself to turn to my own profit. Eight times in succession I
have committed the same robbery at the expense of the same Wasp; eight
times, with unshaken consistency, she has recommenced her fruitless
expedition. Her patience outwore mine; and I left her in undisturbed
possession of her ninth capture.

By this means, or by violating cells already provisioned, I procured
close upon a hundred Weevils; and, notwithstanding what I was entitled
to expect from what Léon Dufour has told us of the habits of the
Buprestis-hunting Cerceris, I could not repress my surprise at the
sight of the singular collection which I had made. Whereas the
Buprestis-slayer, while confining herself to one genus, passes
indiscriminately from one species to another, the more exclusive Great
Cerceris preys invariably on the same species, Cleonus ophthalmicus.
When going through my bag I came upon but one exception, and even that
belonged to a kindred species, Cleonus alternans, a species which I
never saw again in my frequent visits to the Cerceris. Later researches
supplied me with a second exception, in the shape of Bothynoderus
albidus; and that is all. Is this predilection for a single species
adequately explained by the greater flavour and succulence of the prey?
Do the grubs find in this monotonous diet juices which suit them and
which they would not find elsewhere? I do not think so; and, if Léon
Dufour’s Cerceris hunts every sort of Buprestis without distinction,
this is doubtless because all the Buprestes possess the same nutritive
properties. But this must be generally the case with the Weevils also:
their nourishing qualities must be identical; and then this surprising
choice becomes only a question of size and consequently of economy of
labour and time. Our Cerceris, the mammoth of her race, tackles the
Ophthalmic Cleonus by preference because this Weevil is the largest in
our district and perhaps also the commonest. But, if her favourite prey
should fail, she must fall back upon other species, even though they be
smaller, as is proved by the two exceptions stated.

Besides, she is far from being the only one to go hunting at the
expense of the snouted clan, the Weevils. Many other Cerceres,
according to their size, their strength and the accidents of the chase,
capture Weevils varying infinitely in genus, species, shape, and
dimensions. It has long been known that Cerceris arenaria feeds her
grubs on similar provisions. I myself have encountered in her lairs
Sitona lineata, S. tibialis, Cneorinus hispidus, Brachyderes gracilis,
Geonemus flabellipes and Otiorhynchus maleficus. Cerceris aurita is
known to make her booty of Otiorhynchus raucus and Phynotomus
punctatus. The larder of Cerceris Ferreri has shown me the following:
Phynotomus murinus, P. punctatus, Sitona lineata, Cneorinus hispidus,
Rhynchites betuleti. The last, who rolls vine-leaves in the shape of
cigars, is sometimes a superb steel-blue and more ordinarily shines
with a splendid golden copper. I have found as many as seven of these
brilliant insects victualling a single cell; and the gaudiness of the
little subterranean heap might almost stand comparison with the jewels
buried by the Buprestis-huntress. Other species, notably the weaker, go
in for lesser game, whose small size is atoned for by larger numbers.
Thus Cerceris quadricincta stacks quite thirty specimens of Apion
gravidum in each of her cells, without disdaining on occasion such
larger Weevils as Sitona lineata and Phynotomus murinus. A similar
provision of small species falls to the share of Cerceris labiata.
Lastly, the smallest Cerceris in my district, Cerceris Julii, [8]
chases the tiniest Weevils, Apion gravidum and Bruchus granarius,
victims proportioned to the diminutive huntress. To finish with this
list of game, let us add that a few Cerceres observe other gastronomic
laws and raise their families on Hymenoptera. One of these is Cerceris
ornata. We will dismiss these tastes as foreign to the subject in hand.

Of the eight species then of Cerceres whose provisions consist of
Beetles, seven adopt a diet of Weevils and one a diet of Buprestes. For
what singular reasons are the depredations of these Wasps confined to
such narrow limits? What are the motives for this exclusive choice?
What inward likeness can there be between the Buprestes and the
Weevils, outwardly so entirely dissimilar, that they should both become
the food of kindred carnivorous grubs? Beyond a doubt, there are
differences of flavour between this victim and that, nutritive
differences which the larvæ are well able to appreciate; but some
graver reason must overrule all such gastronomic considerations and
cause these curious predilections.

After all the admirable things that have been said by Léon Dufour upon
the long and wonderful preservation of the insects destined for the
flesh-eating larvæ, it is almost needless to add that the Weevils, both
those whom I dug up and those whom I took from between the legs of
their kidnappers, were always in a perfect state of preservation,
though deprived for ever of the power of motion. Freshness of colour,
flexibility of the membranes and the lesser joints, normal condition of
the viscera: all these combine to make you doubt that the lifeless body
before your eyes is really a corpse, all the more as even with the
magnifying-glass it is impossible to perceive the smallest wound; and,
in spite of yourself, you are every moment expecting to see the insect
move and walk. Nay more: in a heat which, in a few hours, would have
dried and pulverized insects that had died an ordinary death, or in
damp weather, which would just as quickly have made them decay and go
mouldy, I have kept the same specimens, both in glass tubes and paper
bags, for more than a month, without precautions of any kind; and,
incredible though it may sound, after this enormous lapse of time the
viscera had lost none of their freshness and dissection was as easily
performed as though I were operating on a live insect. No, in the
presence of such facts, we cannot speak of the action of an antiseptic
and believe in a real death: life is still there, latent, passive life,
the life of a vegetable. It alone, resisting yet a little while longer
the all-conquering chemical forces, can thus preserve the structure
from decomposition. Life is still there, except for movement; and we
have before our eyes a marvel such as chloroform or ether might
produce, a marvel which owes its origin to the mysterious laws of the
nervous system.

The functions of this vegetative life are no doubt enfeebled and
disturbed; but at any rate they are exercised in a lethargic fashion. I
have as a proof the evacuation performed by the Weevils normally and at
intervals during the first week of this deep slumber, which will be
followed by no awakening and which nevertheless is not yet death. It
does not cease until the intestines are emptied of their contents, as
shown by autopsy. Nor do the faint glimmers of life which the insect
still manifests stop at that; and, though irritability of the organs
seems annihilated for good, I have nevertheless succeeded in arousing
slight signs of it. Having placed some recently exhumed and absolutely
motionless Weevils in a bottle containing sawdust moistened with a few
drops of benzine, I was not a little astonished to see their legs and
antennæ moving a quarter of an hour later. For a moment I thought that
I could recall them to life. Vain hope! Those movements, the last
traces of a susceptibility about to be extinguished, soon cease and
cannot be excited a second time. I have tried this experiment in some
cases a few hours after the murderous blow, in others as late as three
or four days after, and always with the same success. Still, the
movement is feeble in proportion to the time that has elapsed since the
fatal stroke. It always spreads from front to back: the antennæ first
wave slowly to and fro; then the front tarsi tremble and take part in
the oscillation; next the tarsi of the second pair of legs and lastly
those of the third pair hasten to do likewise. Once movement sets in,
these different appendages execute their vibrations without any order,
until the whole relapses into immobility, which happens more or less
quickly. Unless the blow has been dealt quite recently, the motion of
the tarsi extends no farther and the legs remain still.

Ten days after an attack I was unable to obtain the least vestige of
susceptibility by the above process; and I then had recourse to the
Voltaic battery. This method is more powerful and provokes muscular
contractions and movements where the benzine-vapour fails. We have only
therefore to apply the current of one or two Bunsen cells through the
conductors of some slender needles. Thrusting the point of one under
the farthest ring of the abdomen and the point of the other under the
neck, we obtain, each time the current is established, not only a
quivering of the tarsi, but a strong reflexion of the legs, which draw
up under the abdomen and then straighten out when the current is turned
off. These flutterings, which are very energetic during the first few
days, gradually diminish in intensity and appear no more after a
certain time. On the tenth day I have still obtained perceptible
movements; on the fifteenth day the battery was powerless to provoke
them, despite the suppleness of the limbs and the freshness of the
viscera. To effect a comparison, I subjected to the action of the
Voltaic pile Beetles really dead, Cellar-beetles, Saperdæ and Lamiæ,
asphyxiated with benzine or sulphuric acid gas. Two hours at most after
the asphyxiation, it was impossible for me to provoke the movements so
easily obtained in Weevils who have already for several days been in
that curious intermediate state between life and death into which their
formidable enemy plunges them.

All these facts are opposed to the idea of something completely dead,
to the theory that we have here a veritable corpse which has become
incorruptible by the action of a preservative fluid. They can be
explained only by admitting that the insect is smitten in the very
origin and mainspring of its movements; that its susceptibility,
suddenly benumbed, dies out slowly, while the more tenacious vegetative
functions die still more slowly and keep the intestines in a state of
preservation for the space of time required by the larvæ.

The particular thing which it was most important to ascertain was the
manner in which the murder is committed. It is quite evident that the
chief part in this must be played by the Cerceris’ venom-laden sting.
But where and how does it enter the Weevil’s body, which is covered
with a hard and well-riveted cuirass? In the various insects pierced by
the assassin’s dart, nothing, even under the magnifying-glass, betrayed
her method. It became a matter, therefore, of discovering the murderous
manœuvres of the Wasp by direct observation, a problem whose
difficulties had made Léon Dufour recoil and whose solution seemed to
me for a time undiscoverable. I tried, however, and had the
satisfaction of succeeding, though not without some preliminary
groping.

When flying from their caverns, intent upon the chase, the Cerceres
would take any direction indifferently, turning now this way, now that;
and they would come back, laden with their prey, from all quarters.
Every part of the neighbourhood must therefore have been explored
without distinction; but, as the huntresses were hardly more than ten
minutes in coming and going, the radius worked could not be one of
great extent, especially when we allow for the time necessary for the
insect to discover its prey, to attack it and to reduce it to an inert
mass. I therefore set myself to inspect the adjacent ground with every
possible attention, in the hope of finding a few Cerceres engaged in
hunting. An afternoon devoted to this thankless task ended by
persuading me of the futility of my quest and of the small chance which
I had of catching in the act a few scarce huntresses, scattered here
and there and soon lost to view through the swiftness of their flight,
especially on difficult ground, thickly planted with vines and
olive-trees. I abandoned the attempt.

By myself bringing live Weevils into the vicinity of the nests, might I
not tempt the Cerceres with a victim all ready to hand and thus witness
the desired tragedy? The idea seemed a good one; and the very next
morning I went off in search of live specimens of Cleonus ophthalmicus.
Vineyards, cornfields, lucerne-crops, hedges, stone-heaps, roadsides: I
visited and inspected one and all; and, after two mortal days of minute
investigation, I was the possessor—dare I say it?—I was the possessor
of three Weevils, flayed, covered with dust, minus antennæ or tarsi,
maimed veterans whom the Cerceres would perhaps refuse to look at! Many
years have passed since the days of that fevered quest when, bathed in
sweat, I made those wild expeditions, all for a Weevil; and, despite my
almost daily entomological explorations, I am still ignorant how and
where the celebrated Cleonus lives, though I meet him occasionally,
roaming on the edge of the paths. O wonderful power of instinct! In the
selfsame places and in a mere fraction of time, our Wasps would have
found by the hundred these insects undiscoverable by man; and they
would have found them fresh and glossy, doubtless just issued from
their nymphal cocoons!

No matter, let us see what we can do with my pitiful bag. A Cerceris
has just entered her gallery with her usual prey; before she comes out
again for a new expedition, I place a Weevil a few inches from the
hole. The insect moves about; when it strays too far, I restore it to
its position. At last the Cerceris shows her wide face and emerges from
the hole; my heart beats with excitement. The Wasp stalks about the
approaches to her home for a few moments, sees the Weevil, brushes
against him, turns round, passes several times over his back and flies
away without honouring my capture with a touch of her mandibles: the
capture which I was at such pains to acquire. I am confounded, I am
floored. Fresh attempts at other holes lead to fresh disappointments.
Clearly these dainty sports-women will have none of the game which I
offer them. Perhaps they find it uninteresting, not fresh enough.
Perhaps, by taking it in my fingers, I have given it some odour which
they dislike. With these epicures a mere alien touch is enough to
produce disgust.

Should I be more fortunate if I obliged the Cerceris to use her sting
in self-defence? I enclosed a Cerceris and a Cleonus in the same bottle
and stirred them up by shaking it. The Wasp, with her sensitive nature,
was more impressed than the other prisoner, with his dull and clumsy
organization; she thought of flight, not of attack. The very parts were
interchanged: the Weevil, becoming the aggressor, at times seized with
his snout a leg of his mortal enemy, who was so greatly overcome with
fear that she did not even seek to defend herself. I was at the end of
my resources; yet my wish to behold the catastrophe was but increased
by the difficulties already experienced. Well, I would try again.

A bright idea flashed across my mind, entering so naturally into the
very heart of the question that it brought hope in its train. Yes, that
must be it; the thing was bound to succeed. I must offer my scorned
game to the Cerceris in the heat of the chase. Then, carried away by
her absorbing preoccupation, she would not perceive its imperfections.

I have already said that, on her return from hunting, the Cerceris
alights at the foot of the slope, at some distance from the hole,
whither she laboriously drags her prey. It became a matter, therefore,
of robbing her of her victim by drawing it away by one foot with my
forceps and at once throwing her the live Weevil in exchange. The trick
succeeded to perfection. As soon as the Cerceris felt her prey slip
from under her belly and escape her, she tapped the ground impatiently
with her feet, turned round and, perceiving the Weevil that had taken
the place of her own, flung herself upon him and clasped him in her
legs to carry him away. But she soon became aware that her prey was
alive; and now the tragedy began, only to end with inconceivable
rapidity. The Wasp faced her victim and, gripping its snout with her
powerful mandibles, soon had it at her mercy. Then, while the Weevil
reared on his six legs, the other pressed her forefeet violently on his
back, as if to force open some ventral joint. I next saw the assassin’s
abdomen slip under the Cleonus’ belly, bend into a curve, and dart its
poisoned lancet briskly, two or three times, into the joint of the
prothorax, between the first and second pair of legs. All was over in a
moment. Without the least convulsive movement, without any of that
stretching of the limbs which accompanies an animal’s death, the victim
fell motionless for all time, as though struck by lightning. It was
terribly and at the same time wonderfully quick. The murderess next
turned the body on its back, placed herself belly to belly with it,
with her legs on either side, clasped it and flew away. Thrice over I
renewed the experiment, with my three Weevils; and the process never
varied.

Of course I gave the Cerceris back her first prey each time and
withdrew my own Cleonus to examine him at my leisure. The inspection
but confirmed my high opinion of the assassin’s formidable skill. It
was impossible to perceive the least sign of a wound, the slightest
flow of vital fluid at the point attacked. But what was most
striking—and justly so—was the prompt and complete annihilation of all
movement. Immediately after the murder I sought in vain for traces of
irritability of the organs in the three Weevils dispatched before my
eyes: those traces were never revealed, whether I pinched or pricked
the insect; and it required the artificial means described above to
provoke them. Thus these powerful Cleoni, which, if pierced alive with
a pin and fixed on the insect-collector’s fatal sheet of cork, would
have kicked and struggled for days and weeks, nay, for whole months on
end, instantly lose all power of movement from the effect of a tiny
prick which inoculates them with an invisible drop of venom. But
chemistry has no poison so potent in so minute a dose; prussic acid
would hardly produce those effects, if indeed it can produce them at
all. It is not to toxology then, surely, but to physiology and anatomy
that we must turn to grasp the cause of this instantaneous
annihilation; and to understand these marvellous happenings we must
consider not so much the intense strength of the poison injected as the
importance of the organ injured.

What is there, then, at the point where the sting enters?



CHAPTER III

A SCIENTIFIC SLAUGHTERER


The wasp has told us part of her secret by showing us the spot which
her sting touches. Does this solve the question? Not yet, nor by a long
way. Let us go back for a moment, forget what the insect has just
taught us and, in our turn, set ourselves the problem of the Cerceris.
The problem is this: to store underground, in a cell, a big enough pile
of game to feed the larva which will be hatched from the egg laid on
the heap.

At first sight this victualling seems simple enough; but a little
reflection shows that it is attended by very grave difficulties. Our
own game, for instance, is brought down by a shot from a gun; it is
killed with horrible wounds. The Wasp has refinements of taste unknown
to us: she must have the prey intact, with all its elegance of form and
colouring, no broken limbs, no gaping wounds, no hideous
disembowelling. Her victim has all the freshness of the live insect; it
retains, without the loss of a single speck, that fine tinted bloom
which is destroyed by the mere contact of our fingers. If the insect
were dead, if it were really a corpse, how great would be our
difficulty in obtaining a like result! Each of us can kill an insect by
brutally crushing it under foot; but to kill it neatly, with no sign of
injury, is not an easy operation, is not an operation which any one can
perform. How many would be utterly perplexed if they were called upon
to kill, then and there, without crushing it, a hardy little insect
which, even when you cut off its head, goes on struggling for a long
time after! One has to be a practical entomologist to think of the
various ways of asphyxiation; and even here success would be doubtful
with primitive methods, such as the fumes of benzine or burning
sulphur. In this unwholesome atmosphere the insect flounders about too
long and loses its glory. We must have recourse to more heroic
measures, such as the terrible exhalations of prussic acid emanating
slowly from strips of paper steeped in cyanide of potassium, or else
and better still, as being free from danger to the insect-hunter, the
all-powerful fumes of bisulphide of carbon. It is quite an art, you
see—and an art which has to call to its aid the formidable arsenal of
chemistry—to kill an insect neatly, to do what the Cerceris performs so
quickly and so prettily, that is, if we are stupid enough to assume
that her captured prey actually becomes a corpse.

A corpse! But that is by no means the fare prescribed for the larvæ,
those little ogres clamouring for fresh meat, whom game ever so
slightly high would inspire with insurmountable disgust. They want meat
killed that day, with no suspicion of taint, the first sign of
corruption. Nevertheless, the prey cannot be packed into the cell
alive, as we pack the cattle destined to furnish fresh meat for the
passengers and crew of a ship. What indeed would become of the delicate
egg laid among live provisions? What would become of the feeble larva,
a tiny grub which the least touch would bruise, among lusty Beetles who
would go on kicking for weeks with their long, spurred legs? We need
here two things which seem utterly irreconcilable: the immobility of
death combined with the sweet wholesomeness of life. Before such a
dietetic problem the most deeply read layman would stand powerless; the
practical entomologist himself would own himself beaten. The Cerceris’
larder would defy their reasoning power.

Let us then suppose an academy of anatomists and physiologists; let us
imagine a congress at which the question is raised among such men as
Flourens, [9] Magendie [10] and Claude Bernard. [11] If we want to
obtain both complete immobility of the victim and also its preservation
during a long period without going bad, the simplest and most natural
idea which comes to us is that of tinned foods. Our congress would
suggest the use of some preserving liquid, just as the famous Landes
scientist did when he was confronted with his Buprestes; they would
attribute exquisite antiseptic virtues to the Wasp’s poison-fluid; but
these strange virtues would still remain to be proved. And perhaps the
conclusion of that learned assembly, like the conclusion of the sage of
the Landes, would be a purely gratuitous supposition which would simply
substitute one unknown quantity for another, giving us in the place of
the mystery of those uncorrupted tissues the mystery of that wonderful
preserving fluid.

If we insist, if we point out that the larvæ need, not preserved food,
which could never possess the properties of still palpitating flesh,
but something that shall be just as if it were live prey, despite its
complete inertia, the learned congress, after due reflection, will fix
on paralysis:

‘Yes, that’s it, of course! The creature must be paralysed; it must be
deprived of movement, without being deprived of life.’

There is only one way of achieving this result: to injure, cut or
destroy the insect’s nervous system in one or more skilfully-selected
places. But, even at that stage, if left in hands unfamiliar with the
anatomical secrets of a delicate organism, the question would not have
advanced much further. What in fact is the disposition of this nervous
system which has to be smitten if we would paralyse the insect without
at the same time killing it? And, first of all, where is it? In the
head, no doubt, and down the back, like the brain and the spinal marrow
of the higher animals.

‘You make a grave mistake,’ our congress would say. ‘The insect is like
an inverted animal, walking on its back; that is to say, instead of
having the spinal marrow on the top, it has it below, along the breast
and the belly. The operation on the insect to be paralysed must
therefore be performed on the lower surface and on that surface alone.’

This difficulty once removed, another arises, equally serious in a
different way. Armed with his scalpel, the anatomist can direct the
point of his instrument wherever he thinks fit, in spite of obstacles,
for these he can eliminate. The Wasp, on the contrary, has no choice.
Her victim is a Beetle in his stout coat of mail; her lancet is her
sting, an extremely delicate weapon which would inevitably be stopped
by the horny armour. Only a few points are accessible to the fragile
implement, namely, the joints, which are protected merely by an
unresisting membrane. Moreover, the joints of the limbs, though
vulnerable, do not in the least fulfil the desired conditions, for the
utmost that could be obtained by means of them would be a partial
paralysis and not a general paralysis affecting the whole of the motor
organism. Without a prolonged struggle, which might be fatal to the
patient, without repeated operations, which, if too numerous, might
jeopardize the Beetle’s life, the Wasp has, if possible, to suppress
all power of movement at one blow. It is essential, therefore, that she
should aim her sting at the nervous centres, the seat of the motor
faculties, whence radiate the nerves scattered over the several organs
of movement. Now these sources of locomotion, these nervous centres,
consist of a certain number of nuclei or ganglia, more numerous in the
larva, less numerous in the perfect insect and arranged along the
median line of the lower surface in a string of beads more or less
distant one from the other and connected by a double ribbon of the
nerve-substance. In all the insects in the perfect state, the so-called
thoracic ganglia, that is to say, those which supply nerves to the
wings and legs and govern their movements, are three in number. These
are the points to be struck. If their action can be destroyed, no
matter how, the power of movement will be destroyed likewise.

There are two methods of reaching these motor centres with the Wasp’s
feeble instrument, the sting: through the joint between the neck and
the corselet; and through the joint between the corselet and the rest
of the thorax, in short, between the first and second pair of legs. The
way through the joint of the neck is hardly suitable: it is too far
from the ganglia, which are near the base of the legs which they endow
with movement. It is at the other point and there alone that the blow
must be struck. That would be the opinion of the academy in which the
Claude Bernards were treating the question in the light of their
profound knowledge. And it is here, just here, between the first and
second pair of legs, on the median line of the lower surface, that the
Wasp inserts her dirk. By what expert instinct is she inspired?

To select, as the spot wherein to drive her sting, the one vulnerable
point, the point which none save a physiologist versed in insect
anatomy could determine beforehand: even that is far from being enough.
The Wasp has a much greater difficulty to surmount; and she surmounts
it with an ease that stupefies us. The nerve-centres governing the
locomotory organs of the insect are, we were saying, three in number.
They are more or less distant from one another; sometimes, but rarely,
they are close together. Altogether they possess a certain independence
of action, so that an injury done to any one of them induces, at any
rate for the moment, the paralysis only of the limbs that correspond
with it, without affecting the other ganglia and the limbs which they
control. To strike in succession these three motor centres, each
farther back than the one before it, and to do so between the first and
second pair of legs, seems an impracticable operation for such a weapon
as the Wasp’s sting, which is too short and is besides very difficult
to guide under such conditions. It is true that certain Beetles have
the three ganglia of the thorax very near together, almost touching,
while others have the last two completely united, soldered, welded
together. It is also a recognized fact that, in proportion as the
different nervous nuclei tend towards a closer combination and greater
centralization, the characteristic functions of animal nature become
more perfect and consequently, alas, more vulnerable. Here we have the
prey which the Cerceris really needs. Those Beetles with motor centres
brought close together or even gathered into a common mass, making them
mutually dependent on one another, will be at the same instant
paralysed with a single stroke of the dagger; or, if several strokes be
needed, the ganglia to be stung will at any rate all be there,
collected under the point of the dart.

Which Beetles are they, then, that constitute a prey so eminently
convenient for paralysing? That is the question. The lofty science of a
Claude Bernard, concerning itself only with the fundamental
generalities of organism and life, would not suffice here; it could
never tell us how to make this entomological selection. I appeal to any
physiologist under whose eyes these lines may come. Without referring
to his library, could he name the Beetles in whom that centralization
of the nervous system occurs; and, even with the aid of his books,
would he at once know where to find the desired information? The fact
is that, with these minute details, we are now entering the domain of
the specialist; we are leaving the public road for the path known to
the few.

I find the necessary information in M. Émile Blanchard’s fine work on
the nervous system of the Coleoptera. [12] I see there that this
centralization of the nervous system is the prerogative, in the first
place, of the Scarabæidæ, or Chafers; but most of these are too large:
the Cerceris could perhaps neither attack them nor carry them away;
besides, many of them live in the midst of ordure where the Wasp,
herself so cleanly, would refuse to go in search of them. Motor centres
very close together are found also in the Histers, who live on carrion
and dung, in an atmosphere of loathsome smells, and who must therefore
be eliminated; in the Scolyti, who are too small; and lastly in the
Buprestes and the Weevils.

What an unexpected light amid the original darkness of the problem!
Among the immense number of Beetles whereon the Cerceres might seem
able to prey, only two groups, the Weevils and the Buprestes, fulfil
the indispensable conditions. They live far removed from stench and
filth, two qualities perhaps invincibly repugnant to the dainty
huntress; their numerous representatives vary considerably in size, in
much the same way as their kidnappers, who can thus pick and choose the
victims that suit them; they are far more vulnerable than any of the
others at the one point where the Wasp’s dart can penetrate, for at
this point the motor centres of the feet and wings are crowded
together, all easily accessible to the sting. At this point, in the
Weevils, the three thoracic ganglia are very close together, the last
two even touching; at the same point, in the Buprestes, the second and
third are mingled in one large mass, very near the first. And it is
just Buprestes and Weevils that we see hunted, to the absolute
exclusion of all other game, by the eight species of Cerceres whose
provisions have been found to consist of Beetles! A certain inward
resemblance, that is to say, the centralization of the nervous system,
must therefore be the reason why the lairs of the different Cerceres
are crammed with victims bearing no outward resemblance whatever.

The most exalted knowledge could make no more judicious choice than
this, by which so great a collection of difficulties is magnificently
solved that we wonder if we be not the dupes of some involuntary
illusion, whether preconceived theoretic notions have not obscured the
actual facts, whether, in short, the pen have not described imaginary
marvels. No scientific conclusion is firmly established until it has
received confirmation by means of practical tests, carried out in every
variety of way. We will therefore subject to experimental proof the
physiological operation of which the Great Cerceris has just apprised
us. If it be possible to obtain artificially what the Wasp obtains with
her sting, namely, the abolition of movement and the continued
preservation of the patient in a perfectly fresh condition; if it be
possible to work this wonder with the Beetles hunted by the Cerceris,
or with those presenting a similar nervous centralization, while we are
unsuccessful with Beetles whose ganglia are far apart, then we shall be
bound to admit, however hard to please we may be in the matter of
tests, that in the unconscious inspiration of her instinct the Wasp has
all the resources of consummate art. Let us see what experiment has to
tell us.

The operating method is of the simplest. It is a question of taking a
needle, or, better and more convenient, the point of a fine steel nib,
and introducing a tiny drop of some corrosive fluid into the thoracic
motor centres, by pricking the insect slightly at the junction of the
prothorax, behind the first pair of feet. The fluid which I employ is
ammonia; but obviously any other liquid as powerful in its action would
produce the same results. The nib being charged with ammonia as it
might be with a very small drop of ink, I give the prick. The effects
obtained differ enormously, according to whether we experiment upon
species whose thoracic ganglia are close together or upon species in
which those same ganglia are far apart. In the first class, my
experiments were made on Dung-beetles: the Sacred Scarab [13] and the
Wide-necked Scarab; on Buprestes: the Bronze Buprestis; lastly, on
Weevils, in particular on the Cleonus hunted by the heroine of this
essay. In the second class, I experimented on Ground-beetles: Carabi,
Procrustes, Chlænii, Sphodri, Nebriæ; on Longicornes: Saperdæ and
Lamiæ; on Melasoma-beetles: Cellar-beetles, Scauri, Asidæ.

In the Scarabæi, the Buprestes and the Weevils the effect is
instantaneous: all movement ceases suddenly, without convulsions, so
soon as the fatal drop has touched the nerve-centres. The Cerceris’ own
sting produces no more speedy annihilation. There is nothing more
striking than this immediate immobility provoked in a powerful Sacred
Beetle.

But this is not the only resemblance between the effects produced by
the Wasp’s sting and those resulting from the nib poisoned with
ammonia. The Scarabs, Buprestes and Beetles artificially stung,
notwithstanding their complete immobility, preserve for three weeks, a
month or even two the perfect flexibility of all their joints and the
normal freshness of their internal organs. Evacuation takes place with
them during the first days as in the normal state; and movements can be
induced by the electric battery. In a word, they behave exactly like
the Beetles immolated by the Cerceris; there is absolute identity
between the state into which the kidnapper puts her victims and that
which we produce at will by injuring the thoracic nerve-centres with
ammonia. Now, as it is impossible to attribute the perfect preservation
of the insect for so long a period to the tiny drop injected, we must
reject altogether any notion of an antiseptic fluid and admit that,
despite its perfect immobility, the insect is not really dead, that it
still retains a glimmer of life, which for some time to come keeps the
organs in their normal condition of freshness, but gradually fades out,
until at last it leaves them the prey of corruption. Besides, in some
cases, the ammonia does not produce complete annihilation of movement
except in the insect’s legs; and then, as the deleterious action of the
liquid has doubtless not extended far enough, the antennæ preserve a
remnant of mobility and we see the insect, even more than a month after
the inoculation, draw them back quickly at the least touch: a
convincing proof that life has not entirely deserted the inanimate
body. This movement of the antennæ is also not uncommon in the Weevils
wounded by the Cerceris.

In every case the injection of ammonia at once stops all movement in
Scarabs, Weevils and Buprestes; but we do not always succeed in
reducing the insect to the condition just described. If the wound be
too deep, if the drop administered be too strong, the victim really
dies; and, in two or three days’ time, we have nothing but a putrid
body before us. If the prick, on the other hand, be too slight, the
insect, after a longer or shorter period of deep torpor, comes to
itself and at least partially recovers its power of motion. The
assailant herself may sometimes operate clumsily, just like man, for I
have noticed this sort of resurrection in a victim stung by the dart of
a Digger-wasp. The Yellow-winged Sphex, whose story will shortly occupy
our attention, stacks her lairs with young Crickets first pricked with
her poisoned lancet. I have extracted from one of those lairs three
poor Crickets whose extreme limpness would, in any other circumstances,
have denoted death. But here again death was only apparent. Placed in a
flask, these Crickets kept in very good condition, perfectly motionless
all the time, for nearly three weeks. In the end, two went mouldy, and
the third partly revived, that is to say, he recovered the power of
motion in his antennæ, in his mouth-parts and, what is more remarkable,
in his first two pair of legs. If the Wasp’s skill sometimes fails to
benumb the victim permanently, one can hardly expect invariable success
from man’s rough experiments.

In the Beetles of the second class, that is to say, those whose
thoracic ganglia are some distance apart, the effect of the ammonia is
quite different. The least vulnerable are the Ground-beetles. A
puncture which would have produced instant annihilation of movement in
a large Sacred Beetle produces nothing but violent and disordered
convulsions in the medium-sized Ground-beetles, be they Chlænius,
Nebria or Calathus. Little by little the insect quiets down and, after
a few hours’ rest, its usual movements are resumed as though it had met
with no accident whatever. If we repeat the experiment on the same
specimen, twice, thrice, or four times over, the results remain the
same, until the wound becomes too serious and the insect actually dies,
as is proved by its desiccation and putrefaction, which follows soon
after.

The Melasoma-beetles and Longicornes are more sensitive to the action
of the ammonia. The injection of the corrosive drop pretty quickly
renders them motionless; and, after a few convulsions, the insect seems
dead. But this paralysis, which would have persisted in the
Dung-beetles, the Weevils and the Buprestes, is only temporary here:
within a day, motion is once more apparent, as energetic as ever. It is
only when the dose of ammonia is of a certain strength that the
movements fail to reappear; but then the insect is dead, quite dead,
for it soon begins to decay. It is impossible, therefore, to produce
complete and persistent paralysis in Beetles that have their ganglia
far apart by the same measures which proved so efficacious in Beetles
with ganglia close together: the utmost that we can obtain is a
temporary paralysis whose effects pass off within a day.

The demonstration is conclusive; the Cerceres that prey on Beetles
conform in their selection to what could be taught only by the most
learned physiologists and the finest anatomists. One would vainly
strive to see no more in this than casual coincidences: it is not in
chance that we shall find the key to such harmonies as these.



CHAPTER IV

THE YELLOW-WINGED SPHEX


Under their powerful armour, which no dart can penetrate, the insects
of the Beetle tribe offer but a single vulnerable spot to the
sting-bearing enemy. This defect in the breastplate is known to the
murderess, who drives in her poisoned dagger there and at one blow
strikes the three motor centres, for she selects her victims from the
Weevil and Buprestis families, whose nervous system is centralized to
the requisite degree. But what will happen when the prey is an insect
clad not in mail but in a soft skin, which the Wasp can stab here or
there indifferently, in any part of the body that chances to be
exposed? In that case are the blows still delivered scientifically?
Like the assassin who strikes at the heart to cut short the dangerous
resistance of his victim, does the assailant follow the tactics of the
Cerceres and wound the motor ganglia by preference? If that be so, then
what happens when these ganglia are some distance apart and so
independent in their action that paralysis of one is not necessarily
followed by paralysis of the others? These questions will be answered
by the story of a Cricket-huntress, the Yellow-winged Sphex (Sphex
flavipennis).

It is at the end of July that the Yellow-winged Sphex tears the cocoon
that has protected her until then and flies out of her subterranean
cradle. During the whole of August she is frequently seen flitting, in
search of some drop of honey, around the spiked heads of the field
eryngo, the commonest of the hardy plants that brave the heat of the
dog-days in this month. But this careless life does not last long, for
by the beginning of September the Sphex is at her arduous task as a
sapper and huntress. She generally selects some small plateau, on the
high banks by the side of the roads, wherein to establish her home,
provided that she find two indispensable things there: a sandy soil,
easy to dig; and sunshine. No other precaution is taken to protect the
dwelling against the autumn rains or winter frosts. A horizontal site,
unprotected, lashed by the rain and the winds, suits her perfectly, on
condition, however, that it is exposed to the sun. And, when a heavy
shower comes in the middle of her mining, it is pitiful next day to see
the half-built galleries in ruins, choked with sand and finally
abandoned by their engineers.

The Sphex seldom practises her industry alone; the site selected is
usually exploited by small bands of ten or twenty sappers or more. One
must have spent days in contemplating one of these villages to form any
idea of the restless activity, the spasmodic haste, the abrupt
movements of those hard-working miners. The soil is rapidly attacked
with the rakes of the forefeet: canis instar, as Linnæus says. No
mischievous puppy displays more energy in digging up the ground. At the
same time, each worker sings her glad ditty, which consists of a shrill
and strident noise, constantly broken off and modulated by the
vibrations of the wings and thorax. One would think that they were a
troop of merry companions encouraging one another in their work with a
cadenced rhythm. Meanwhile the sand flies, falling in a fine dust on
their quivering wings; and the too bulky gravel, removed bit by bit,
rolls far away from the workyard. If a piece seems too heavy to be
moved, the insect gets up steam with a shrill note which reminds one of
the woodman’s ‘Hoo!’ Under the redoubled efforts of tarsi and mandibles
the cave soon takes shape; the insect is already able to dive into it
bodily. We then see a lively alternation of forward movements, to
loosen new materials, and backward movements, to sweep the rubbish
outside. In this constant hurrying to and fro the Sphex does not walk,
she darts as though shot from a spring; she bounds with throbbing
abdomen and quivering antennæ, her whole body, in short, animated with
a musical vibration. The miner is now out of sight; but we still hear
underground her untiring song, while at intervals we catch a glimpse of
her hind-legs, pushing a torrent of sand backwards to the mouth of the
burrow. From time to time the Sphex interrupts her subterranean
labours, either to come and dust herself in the sun, to rid herself of
the grains of sand which, slipping into her delicate joints, might
hamper the liberty of her movements, or else to reconnoitre the
neighbourhood. Despite these interruptions, which for that matter do
not last long, the gallery is dug in the space of a few hours; and the
Sphex comes to her threshold to chant her triumph and give the
finishing polish to her work by removing some unevenness and carrying
away a speck or two of earth whose drawbacks are perceptible to her
discerning eye alone.

Of the numerous tribes of Sphex-wasps which I have visited, one in
particular remains fixed in my memory because of its curious
dwelling-place. On the edge of a high-road were some small heaps of
mud, taken from the ditches by the road-mender’s shovel. One of these
heaps, long ago dried in the sun, formed a cone-shaped mound,
resembling a large sugar-loaf twenty inches high. The site seemed to
have attracted the Wasps, who had established themselves there in a
more populous colony than I have ever since beheld. The cone of dry mud
was riddled from top to bottom with burrows, which gave it the
appearance of an enormous sponge. On every storey there was a feverish
animation, a busy coming and going which reminded one of the scenes in
some great yard when the work is urgent. Crickets were being dragged by
the antennæ up the slopes of the conical city; victuals were being
stored in the larders of the cells; dust was pouring from the galleries
in process of excavation by the miners; grimy faces appeared at
intervals at the mouths of the tunnels; there were constant exits and
constant entrances; and now and again a Sphex, in her brief intervals
of leisure, would climb to the top of the cone, perhaps to cast a look
of satisfaction from this belvedere over the works in general. What a
spectacle to tempt me, to make me long to carry the whole city and its
inhabitants away with me! It was useless even to try: the mass was too
heavy. One cannot root up a village from its foundations to transplant
it elsewhere.

We will return, therefore, to the Sphex-wasps working on level ground,
in ordinary soil, as happens in by far the greater number of cases. As
soon as the burrow is dug, the chase begins. Let us profit by the
Wasp’s distant excursions in search of her game and examine the
dwelling. The usual site of a Sphex colony is, as I said, level ground.
Nevertheless, the soil is not so smooth but that we find a few little
mounds crowned with a tuft of grass or wormwood, a few cracks
consolidated by the scanty roots of the vegetation that covers them. It
is in the sides of these furrows that the Sphex builds her dwelling.
The gallery consists first of a horizontal portion, two or three inches
long and serving as an approach to the hidden retreat destined for the
provisions and the larvæ. It is in this entrance-passage that the Sphex
takes shelter in bad weather; it is here that she retires for the night
and rests for a few moments in the daytime, putting outside only her
expressive face, with its great, bold eyes. Following on the vestibule
comes a sudden bend, which descends more or less obliquely to a depth
of two or three inches more and ends in an oval cell of somewhat larger
diameter, whose main axis lies horizontally. The walls of the cell are
not coated with any particular cement; but, in spite of their bareness,
we can see that they have been the object of the most conscientious
labour. The sand has been heaped up and carefully levelled on the
floor, the ceiling and the sides, so as to prevent landslips and remove
any roughness that might hurt the delicate skin of the grub. Lastly,
this cell communicates with the passage by a narrow entrance, just wide
enough to admit the Sphex laden with her prey.

When this first cell is supplied with an egg and the necessary
provisions, the Sphex walls up the entrance, but does not yet abandon
her burrow. A second cell is dug beside the first and victualled in the
same way; then a third and sometimes a fourth. Not till then does the
Sphex shoot back into the burrow all the rubbish accumulated outside
the door and completely remove all the outward traces of her work.
Thus, to each burrow there are usually three cells, rarely two and
still more rarely four. Now, as we ascertain when dissecting the
insect, we can estimate the number of eggs laid at about thirty, which
brings up to ten the number of burrows needed. On the other hand, the
operations are hardly begun before September and are finished by the
end of the month. The Sphex, therefore, can devote only two or three
days at most to each burrow and its provisioning. No one will deny that
the active little creature has not a moment to lose, when, in so short
a time, she has to excavate her den, to procure a dozen Crickets, to
carry them sometimes from a distance in the face of innumerable
difficulties, to store them away and finally to stop up the burrow.
And, besides, there are days when the wind makes hunting impossible,
rainy days or even merely grey days, which cause all work to be
suspended. One can readily imagine from this that the Sphex is unable
to give to her buildings the perhaps permanent solidity which the Great
Cerceres bestow upon their long galleries. The latter hand down from
generation to generation their substantial dwellings, each year
excavated to a greater depth than the last, galleries which threw me
into a sweat when I tried to inspect them and which generally triumphed
over my efforts and my implements. The Sphex does not inherit the work
of her predecessors: she has to do everything for herself and quickly.
Her dwelling is but a tent, hastily pitched for a day and shifted on
the morrow. As compensation, the larvæ, who have only a thin layer of
sand to cover them, are capable themselves of providing the shelter
which their mother could not create: they clothe themselves in a
threefold and fourfold waterproof wrapper, far superior to the thin
cocoon of the Cerceres.

But here, with a loud buzz, comes a Sphex who, returning from the
chase, stops on a neighbouring bush, holding in her mandibles, by one
antenna, a large Cricket, several times her own weight. Exhausted by
the burden, she takes a moment’s rest. Then she once more grips her
captive between her feet and, with a supreme effort, covers in one
flight the width of the ravine that separates her from her home. She
alights heavily on the level ground where I am watching, in the very
middle of a Sphex village. The rest of the journey is performed on
foot. The Wasp, not at all intimidated by my presence, bestrides her
victim and advances, bearing her head proudly aloft and hauling the
Cricket, who trails between her legs, by an antenna held in her
mandibles. If the ground be bare, it is easy to drag the victim along;
but, should some grass-tuft spread the network of its shoots across the
road, it is curious to observe the amazement of the Sphex when one of
these little ropes suddenly thwarts her efforts; it is curious to
witness her marches and counter-marches, her reiterated attempts, until
the obstacle is overcome, either with the aid of the wings or by means
of a clever deviation. The Cricket is at last conveyed to his
destination and is so placed that his antennæ exactly touch the mouth
of the burrow. The Sphex then abandons her prey and descends hurriedly
to the bottom of the cave. A few seconds later we see her reappear,
showing her head out of doors and giving a little cry of delight. The
Cricket’s antennæ are within her reach; she seizes them and the game is
brought quickly down to the lair.

I still ask myself, without being able to find a sufficiently
convincing solution, the reason for these complicated proceedings at
the moment when the Cricket is introduced into the burrow. Instead of
going down to her den alone, to reappear afterwards and pick up the
prey left for a time on the threshold, would not the Sphex have done
better to continue to drag the Cricket along the gallery as she does in
the open air, seeing that the width of the tunnel permits it, or else
to go in first, backwards, and pull him after her? The various
Predatory Wasps whom I have hitherto been able to observe carry down to
their cells straight away, without preliminaries, the game which they
hold clasped beneath their bellies with the aid of their mandibles and
their middle-legs. Léon Dufour’s Cerceris begins by complicating her
procedure, because, after laying her Buprestis for a moment at the door
of her underground home, she at once enters her gallery backwards and
then seizes the victim with her mandibles and drags it to the bottom of
the burrow. But it is a far cry from these tactics and those adopted in
a like case by the Cricket-hunters. Why that domiciliary visit which
invariably precedes the entrance of the game? Could it not be that,
before descending with a cumbrous burden, the Sphex thinks it wise to
take a look at the bottom of her dwelling, so as to make sure that all
is well and, if necessary, to drive out some brazen parasite who may
have slipped in during her absence? If so, who is the parasite? Several
Diptera, Predatory Gnats, especially Tachinæ, watch at the doors of the
Hunting Wasps, spying for the propitious moment to lay their eggs on
others’ provisions; but none of them enters the home or ventures into
the dark passages where the owner, if by ill-luck she happened to be
in, would perhaps make them pay dearly for their audacity. The Sphex,
like all the rest, pays her tribute to the plundering Tachinæ; but
these never enter the burrow to perpetrate their misdeeds. Besides,
have they not all the time that they need to lay their eggs on the
Cricket? If they are sharp about it, they can easily profit by the
temporary abandonment of the victim to entrust their progeny to it.
Some greater danger still must therefore threaten the Sphex, since her
preliminary descent of the burrow is of such imperious necessity.

Here is the only fact observed by myself that may throw a little light
on the problem. Amid a colony of Sphex-wasps in full swing, a colony
from which any other Wasp is usually excluded, I one day surprised a
huntress of a different genus, Tachytes nigra, carrying one by one,
without hurrying, in the midst of the crowd where she was but an
intruder, grains of sand, bits of little dry stalks and other
diminutive materials to stop up a burrow of the same shape and width as
the adjacent burrows of the Sphex. The labour was too carefully
performed to allow of any doubt of the presence of the worker’s egg in
the tunnel. A Sphex moving about uneasily, apparently the lawful owner
of the burrow, did not fail, each time that the strange Wasp entered
the gallery, to rush in pursuit of her; but she emerged swiftly, as
though frightened, followed by the other, who impassively continued her
work. I inspected this burrow, evidently an object in dispute between
the two Wasps, and found in it a cell provisioned with four Crickets.
Suspicion almost makes way for certainty: these provisions are far in
excess of the needs of a Tachytes-grub, who is certainly not more than
half the size of the larva of the Sphex. She whose impassiveness, whose
care to stop up the burrow would at first have made one take her for
the mistress of the house, was in reality a mere usurper. How is it
that the Sphex, who is larger and more powerful than her adversary,
allows herself to be robbed with impunity, confining herself to
fruitless pursuits and fleeing like a coward when the interloper, who
does not even appear to notice her presence, turns round to leave the
burrow? Can it be that, in insects as in man, the first chance of
success lies in de l’audace, encore de l’audace et toujours de
l’audace? The usurper certainly had audacity and to spare. I see her
still, with imperturbable calmness, moving in and out in front of the
complaisant Sphex, who stamps her feet with impatience but does not
fall upon the thief.

I will add that, in other circumstances, I have repeatedly found the
same Wasp, whom I presume to be a parasite, in short the Black
Tachytes, dragging a Cricket by one of his antennæ. Was he a
lawfully-acquired prey? I should like to think so; but the vacillating
behaviour of the insect, who went straying about the ruts in the roads
as though seeking for a burrow to suit it, always left me uncertain. I
have never witnessed its digging-work, if it really undertakes the
labour of excavation. And, a more serious matter, I have seen it leave
its game on the rubbish-heap, perhaps not knowing what to do with it,
for lack of a burrow wherein to place it. Such wastefulness as this
seems to me to point to ill-gotten goods; and I ask myself if the
Cricket were not stolen from the Sphex at the moment when she abandoned
her prey on the threshold. My suspicions also fall upon Tachytes
obsoleta, banded with white round the abdomen like Sphex albisecta and
feeding her larvæ on Crickets similar to those hunted by the latter. I
have never seen her digging any galleries, but I have caught her with a
Cricket whom the Sphex would not have rejected. This identity of
provisions in species of different genera raises doubts in my mind as
to the lawfulness of the booty. Let me add, lastly, to atone in a
measure for the injury which my suspicions may do to the reputation of
the genus, that I have been the eye-witness of a perfectly
straightforward capture of a small and still wingless Cricket by
Tachytes tarsina and that I have seen her digging cells and victualling
them with game acquired by her own valiant exertions.

I have therefore only suspicions to offer in explanation of the
obstinacy of the Sphex-wasps in going down their tunnels before
carrying in their prey. Can they have some other object besides that of
dislodging a parasite who may have arrived during their absence? This
is what I despair of ever knowing; for who can interpret the thousand
ruses of instinct? Poor human reason, which cannot even fathom the
wisdom of a Sphex!

At any rate, it has been proved that these ruses are singularly
invariable. In this connection I will mention an experiment which
interested me greatly. Here are the particulars: at the moment when the
Sphex is making her domiciliary visit, I take the Cricket left at the
entrance to the dwelling and place her a few inches farther away. The
Sphex comes up, utters her usual cry, looks here and there in
astonishment, and, seeing the game too far off, comes out of her hole
to seize it and bring it back to its right place. Having done this, she
goes down again, but alone. I play the same trick upon her; and the
Sphex has the same disappointment on her arrival at the entrance. The
victim is once more dragged back to the edge of the hole, but the Wasp
always goes down alone; and this goes on as long as my patience is not
exhausted. Time after time, forty times over, did I repeat the same
experiment on the same Wasp; her persistency vanquished mine and her
tactics never varied.

Having demonstrated the same inflexible obstinacy which I have just
described in the case of all the Sphex-wasps on whom I cared to
experiment in the same colony, I continued to worry my head over it for
some time. What I asked myself was this:

‘Does the insect obey a fatal tendency, which no circumstances can ever
modify? Are its actions all performed by rule; and has it no power of
acquiring the least experience on its own account?’

Some additional observations modified this too absolute view. Next year
I visit the same spot at the proper season. The new generation has
inherited the burrowing-site selected by the previous generation; it
has also faithfully inherited its tactics: the experiment of
withdrawing the Cricket yields the same results. Such as last year’s
Sphex-wasps were, such are those of the present year, equally
persistent in a fruitless procedure. The illusion was simply growing
worse, when good fortune brought me into the presence of another colony
of Sphex-wasps, in a district at some distance from the first. I
recommenced my attempts. After two or three experiments with results
similar to those which I had so often obtained, the Sphex got astride
of the Cricket, seized him with her mandibles by the antennæ, and at
once dragged him into the burrow. Who was the fool now? Why, the
experimenter foiled by the clever Wasp! At the other holes, her
neighbours likewise, one sooner, another later, discovered my treachery
and entered the dwelling with the game, instead of persisting in
abandoning it on the threshold to seize it afterwards. What did all
this mean? The colony which I was now inspecting, descended from
another stock—for the children return to the site selected by their
parents—was cleverer than the colony of the year before. Craft is
handed down: there are tribes that are sharper-witted and tribes that
are duller-witted, apparently according to the faculties of their
elders. With the Sphex as with us, the intellect differs with the
province.

Next day, in a different locality, I repeated my experiment with
another Cricket; and every time the Sphex was hoodwinked. I had come
upon a dense-minded tribe, a regular village of Bœotians, as in my
first observations.



CHAPTER V

THE THREE DAGGER-THRUSTS


There is no doubt that the Sphex displays her most cunning resources at
the moment of immolating a Cricket; it is important, therefore, to
ascertain the manner wherein the victim is sacrificed. Profiting by the
repeated attempts which I had made when I was studying the tactics of
the Cerceres, I at once applied to the Sphex the method which had
succeeded with the other Wasps, a method that consisted in taking the
prey from the huntress and forthwith replacing it by another, living
prey. The substitution is all the easier inasmuch as we have seen the
Sphex herself releasing her victim in order to go down the burrow for a
moment alone. Her daring familiarity, which makes her come and take
from your fingers and even out of your hand the Cricket whom you have
stolen from her and now offer her again, also lends itself admirably to
the successful issue of the experiment, by allowing you to observe
every detail of the drama closely.

Again, to find live Crickets is an easy matter: we have but to lift the
first stone that we see and we find them crouching underneath,
sheltered from the sun. These Crickets are young ones, of the same
year, who as yet boast but rudimentary wings and who, not possessing
the industry of the full-grown insect, have not learnt to dig those
cavernous retreats where they would be safe from the Sphex’
investigations. In a few moments I have as many live Crickets as I
could wish for. This completes my preparations. I climb to the top of
my observatory, establish myself on the level ground, in the centre of
the Sphex village, and wait.

A huntress appears upon the scene, carts her Cricket to the entrance of
the home and goes down her burrow by herself. I quickly remove the
Cricket and substitute one of mine, placing him, however, some distance
away from the hole. The kidnapper returns, looks round, and runs and
seizes the victim, which is too far off for her. I am all eyes, all
attention. Nothing would induce me to give up my part in the tragic
spectacle which I am about to witness. The terrified Cricket takes to
flight, hopping as fast as he can; the Sphex pursues him hot-foot,
reaches him, rushes upon him. There follows, amid the dust, a confused
encounter, wherein each champion, now victor, now vanquished, by turns
is at the top or at the bottom. Success, for a moment undecided, at
last crowns the aggressor’s efforts. Despite his vigorous kicks,
despite the snaps of his pincer-like mandibles, the Cricket is laid low
and stretched upon his back.

The murderess soon makes her arrangements. She places herself belly to
belly with her adversary, but in the opposite direction, grasps one of
the threads at the tip of the Cricket’s abdomen with her mandibles and
masters with her fore-legs the convulsive efforts of his thick hinder
thighs. At the same time, her middle-legs hug the heaving sides of the
beaten insect; and her hind-legs, pressing like two levers on the front
of the head, force the joint of the neck to open wide. The Sphex then
curves her abdomen vertically, so as to offer only an unattackable
convex surface to the Cricket’s mandibles; and we see, not without
emotion, its poisoned lancet drive once into the victim’s neck, next
into the joint of the front two segments of the thorax, and lastly
towards the abdomen. In less time than it takes to relate, the murder
is consummated; and the Sphex, after adjusting the disorder of her
toilet, makes ready to haul home the victim, whose limbs are still
quivering in the throes of death.

Let us consider for a moment the excellence of the tactics of which I
have given a feeble glimpse. The Cerceris attacks a passive adversary,
incapable of flight, almost devoid of offensive weapons, whose sole
chances of safety lie in a stout cuirass, the weak point of which,
however, is known to the murderess. But what a difference here! The
quarry is armed with dreadful mandibles, capable of disembowelling the
assailant if they succeed in seizing her; it sports a pair of powerful
legs, regular clubs bristling with a double row of sharp spikes, which
can be used either to enable the Cricket to hop out of his enemy’s
reach, or to send her sprawling with brutal kicks. Observe, therefore,
the precautions which the Sphex takes before setting her sting in
motion. The victim, turned upon his back, cannot, for lack of any
purchase, use his hind-levers to escape with, which he certainly would
do if he were attacked in the normal position, as are the big Weevils
of the Great Cerceris. His spurred legs, mastered by the Sphex’
fore-feet, cannot act as offensive weapons either; and his mandibles,
kept at a distance by the Wasp’s hind-legs, open in wide menace without
being able to seize a thing. But it is not enough for the Sphex to
render her Cricket incapable of hurting her; she must also hold him so
firmly pinioned that he cannot make the slightest movement capable of
diverting the sting from the points at which the poison is to be
injected; and it is probably with the object of stilling the movements
of the abdomen that one of its terminal threads is grasped. No, if a
fertile imagination had allowed itself free scope to invent a plan of
attack at will, it could not have contrived anything better; and it is
open to doubt whether the athletes of the classic palestræ, when
grappling with an adversary, boasted more scientific attitudes.

I have said that the sting is driven several times into the patient’s
body: first under the neck, then behind the prothorax, next and lastly
towards the top of the abdomen. It is in these three dagger-thrusts
that the infallibility and the intuitive science of instinct appear in
all their splendour. Let us first recall the principal conclusions to
which our earlier study of the Cerceris has led us. The victims of the
Wasps whose larvæ live on prey are not proper corpses, in spite of
their immobility, which is sometimes complete. They suffer simply from
a total or partial locomotory paralysis, from a more or less thorough
annihilation of animal life; but vegetable life, the life of the organs
of nutrition, is maintained for a long while yet and preserves from
decomposition the prey which the larva is not to devour for some time
to come. To produce this paralysis the Hunting Wasps employ precisely
the process which the advanced science of our own day might suggest to
the experimental physiologists, that is to say, they injure, by means
of their poisoned sting, the nerve-centres that control the locomotory
organs. We know besides that the several centres or ganglia of the
nervous system of articulate animals are, within certain limits,
independent of one another in their action, so that an injury to any
one of them does not, or at any rate not immediately, entail more than
the paralysis of the corresponding segment; and this applies all the
more when the different ganglia are farther apart. When, on the other
hand, they are welded together, the lesion of this common centre
induces paralysis of all the segments over which its ramifications are
distributed. This is the case with the Buprestes and the Weevils, whom
the Cerceres paralyse with a single thrust of the sting, aimed at the
common mass of the nerve-centres of the thorax. But open a Cricket.
What do we find to set the three pairs of legs in motion? We find what
the Sphex knew long before the anatomists: three nerve-centres at a
great distance one from the other. Hence the magnificent logic of her
needle-thrusts thrice repeated. Proud science, bend the knee!

Despite the appearances that might make us think otherwise, the
Crickets immolated by the Yellow-winged Sphex are no more dead than the
Weevils pierced by the Cerceris’ dart. The flexibility of the victims’
integuments, faithfully revealing the slightest internal movement,
enables us in this case to dispense with the artificial methods which I
employed to demonstrate the presence of a remnant of life in the Cleoni
of the Great Cerceris. In fact, if we assiduously observe a Cricket
stretched on his back, a week, a fortnight even or more after the
murder, we see the abdomen heaving deeply at long intervals. Pretty
often we can still perceive a few quiverings in the palpi and
exceedingly-pronounced movements on the part of both the antennæ and
the abdominal threads, which diverge and separate and then suddenly
come together. I have succeeded, by placing the sacrificed Crickets in
glass tubes, in keeping them perfectly fresh for a month and a half.
Consequently, the Sphex-grubs, which live for less than a fortnight
before shrouding themselves in their cocoons, are certain of fresh meat
until their banquet is finished.

The chase is over; the three or four Crickets that are the allotted
portion of each cell are stacked methodically, lying on their backs,
with their heads at the far end of the cell and their feet at the
entrance. An egg is laid on one of them. The burrow must now be closed.
The sand resulting from the excavation, which is lying in a heap
outside the front-door, is quickly swept backwards down the passage.
From time to time some fair-sized bits of gravel are picked out singly,
by scratching the heap of rubbish with the fore-feet, and carried with
the mandibles to strengthen the crumbly mass. Should the Wasp find none
within reach to suit her, she goes and searches for them in the
neighbourhood, and seems to choose them as conscientiously as a mason
would choose the chief stones for his building. Vegetable remains, tiny
fragments of dead leaves, are also employed. In a few moments every
outward trace of the underground dwelling has disappeared; and, if we
have not been careful to mark the site of the abode, it becomes
impossible for the most watchful eye to find it again. When this is
finished, a new burrow is dug, provisioned and walled up as often as
the teeming ovaries demand. Having completed the laying of her eggs,
the Sphex resumes her careless, vagrant life, until the first cold snap
puts an end to her well-filled existence.

The Sphex’ task is accomplished; and I will finish mine with an
examination of her weapon. The organ destined for the elaboration of
her poison consists of two prettily-ramified tubes, ending separately
in a common reservoir or phial, shaped like a pea. From this phial
starts a slender channel which runs down the axis of the sting and
conducts the little drop of poison to its tip. The dimensions of the
lancet are very small and not such as one would expect from the size of
the Sphex, and especially from the effects which its prick produces on
the Crickets. The point is quite smooth and entirely deprived of those
backward indentations which we find in the Hive-bee’s sting. The reason
for this is obvious. The Bee uses her sting only to avenge an injury,
even at the cost of her life; and the teeth of the dart resist its
withdrawal from the wound and thus cause mortal ruptures in the viscera
at the extremity of the abdomen. What would the Sphex have done with a
weapon that would have been fatal to her on her first expedition?
Supposing that the dart could be withdrawn in spite of its teeth, I
doubt whether any Hymenopteron using her weapon chiefly to wound the
game destined for her larvæ would be supplied with a toothed sting.
With her, the dirk is not a show weapon, unsheathed to satisfy revenge:
revenge, the so-called pleasure of the gods, but a very costly
pleasure, for the vindictive Bee sometimes pays for it with her life;
it is an implement for use, a tool, on which the future of the grubs
depends. It must therefore be one easy to wield in the struggle with
the captured prey; it must be capable of being inserted in the flesh
and withdrawn without the least hesitation, a condition much better
fulfilled by a smooth than by a barbed blade.

I wished to find out at my own expense if the Sphex’ sting is very
painful, this sting which lays low sturdy victims with terrible
rapidity. Well, I confess with profound admiration that it is
insignificant and bears no comparison, for intensity of pain, with the
stings of the irascible Bees and Social Wasps. It hurts so little that,
instead of using the forceps, I would not scruple to take in my fingers
any live Sphex-wasps that I needed in my experiments. I can say the
same of the different Cerceres, of the Philanthi, [14] of the Palari,
of even the huge Scoliæ, [15] whose very view inspires dismay, and,
generally speaking, of all the Hunting Wasps that I have been able to
observe. I make an exception of the Spider-huntresses, the Pompili;
[16] and even then their sting is much less painful than the Bees’.

One last word: we know how furiously the Hymenoptera armed with a
purely defensive dart—the Social Wasps, for instance—rush upon him who
is bold enough to disturb their dwelling-house and punish him for his
temerity. On the other hand, those whose sting is intended for killing
game are very pacific, as though they were aware of the importance
which the little drop of poison in their phial possesses for their
family. This tiny drop is the safeguard of their race, I might say, its
livelihood; and so they are very economical in its use, reserving it
for the serious business of the chase, without any parade of vindictive
courage. I was not once punished with a sting when I established myself
amid the villages of our various Hunting Wasps, though I overturned
their nests and stole the larvæ and the provisions. You must lay hold
of the insect to make it use its weapon; and even then it does not
always pierce the skin, unless you place within its reach a part more
delicate than the fingers, such as, for instance, the wrist.



CHAPTER VI

THE LARVA AND THE NYMPH


The egg of the Yellow-winged Sphex is white, elongated, cylindrical,
slightly bow-shaped and measures three to four millimetres [17] in
length. So far from being laid anywhere on the victim, at random, it is
deposited on a specially favoured spot, which is always the same; in
short, it is placed across the Cricket’s breast, a little to one side,
between the first and second pair of legs. The egg of the White-edged
Sphex and that of the Languedocian Sphex occupy a similar position: the
first on the breast of a Locust, the second on the breast of an
Ephippiger. [18] The point selected must present some peculiarity of
great importance to the young larva’s safety, for I have never known it
to vary.

The egg hatches after three or four days. A very delicate wrapper tears
asunder; and there lies before our eyes a feeble grub, transparent as
crystal, a little attenuated and as it were compressed in front,
slightly swollen at the back and adorned on either side with a narrow
white thread formed of the principal trachean ducts. The frail creature
occupies the same position as the egg. Its head is, so to speak,
planted at the very spot where the upper end of the egg was fixed; and
all the remainder simply rests upon the victim, without being fastened
to it. The grub’s transparency enables us readily to distinguish rapid
undulations inside it, ripples which follow one upon the other with
mathematical regularity and which, beginning in the middle of the body,
spread some forward and some backward. These fluctuating movements are
due to the digestive canal, which takes long draughts of the juices
drawn from the victim’s body.

Let us dwell for a moment upon a sight which cannot fail to attract our
attention. The Wasp’s prey lies on its back, motionless. In the cell of
the Yellow-winged Sphex it is a Cricket, or rather three or four
Crickets stacked one atop the other; in the cell of the Languedocian
Sphex it is a single head of game, but large in proportion, a
fat-bellied Ephippiger. The grub is lost should it happen to be torn
from the spot whence it derives life; a fall would be the end of it,
for, weak as it is and deprived of all means of motion, how could it
make its way back to the spot at which it slakes its appetite? The
slightest movement would enable the victim to rid itself of the atom
gnawing at its entrails; and yet the gigantic prey submits meekly,
without the least quiver of protest. I well know that it is paralysed,
that it has lost the use of its legs through the sting of its
murderess; but still, recent victim that it is, it retains more or less
power of movement and sensation in the regions not affected by the
dart. The abdomen throbs, the mandibles open and close, the abdominal
filaments wave to and fro, as do the antennæ. What would happen if the
worm were to bite into one of the still impressionable parts, near the
mandibles, or even on the belly, which, being more tender and more
succulent, seems as though it ought, after all, to supply the first
mouthfuls of the feeble grub? Bitten to the quick, the Cricket, Locust
or Ephippiger would at least shiver; and this faint tremor of the skin
would be enough to shake off the tiny larva and bring it to the ground,
where it would no doubt perish, for it might at any moment find itself
in the grips of those dreadful mandibles.

But there is one part of the body where no such danger is to be feared,
the part which the Wasp has wounded with her sting—in short, the
thorax. Here and here alone, on a victim of recent date, the
experimenter can rummage with a needle, driving it through and through,
without producing a sign of suffering in the patient. Well, it is here
that the egg is invariably laid; it is here that the young larva always
takes its first bite at its prey. Gnawed at a point no longer
susceptible to pain, the Cricket remains motionless. Later, when the
wound has reached a sensitive point, he will doubtless toss about to
such extent as he can; but then it will be too late: his torpor will be
too deep; and besides the enemy will have gained strength. This
explains why the egg is laid on a spot which never varies, near the
wounds caused by the sting—in short, on the thorax: not in the middle,
where the skin would perhaps be too thick for the new-born grub, but on
one side, towards the juncture of the legs, where it is much thinner.
What a judicious choice, how logical on the part of the mother when,
underground, in complete darkness, she discerns the one suitable spot
on the victim and selects it for her egg!

I have reared Sphex-grubs by giving them, one after the other, the
Crickets taken from the cells; and I was then able to follow day by day
the rapid progress of my nurselings. The first Cricket, the one on whom
the egg was laid, is attacked, as I have said, near the point where the
huntress administered her second sting, that is to say, between the
first and second pair of legs. In a few days the young larva has dug in
the victim’s breast a hollow large enough to admit half its body. It is
not uncommon to see the Cricket, bitten to the quick, uselessly waving
his antennæ and his abdominal threads, opening and closing his
mandibles on space and even moving a leg. But the enemy is safe and is
ransacking his entrails with impunity. What an awful nightmare for the
paralysed Cricket!

The first ration is finished in six or seven days’ time; none of it
remains but the framework of skin, with all its parts more or less in
position. The larva, whose length is now twelve millimetres, [19]
leaves the Cricket’s body through the hole in the thorax which it made
to start with. During this operation it moults; and its cast skin often
remains caught in the opening through which it made its exit. It rests
after the moulting and then attacks a second ration. Being stronger
now, the larva has nothing to fear from the feeble movements of the
Cricket, whose daily-increasing torpor has had time to extinguish the
last glimmers of resisting-power during the week and more that has
elapsed since the dagger-thrusts were given. It is therefore assailed
with no precautions, usually at the belly, which is the tenderest part
and the richest in juices. Soon the turn comes of the third Cricket and
lastly of the fourth, who is devoured in ten hours or so. Of these last
three victims all that remains is the tough integuments, whose various
parts are severed one by one and carefully emptied. If a fifth ration
be presented, the larva scorns it, or hardly touches it, not from
abstemiousness, but from imperious necessity. For observe that hitherto
the larva has ejected no excrement and that its intestines, into which
four Crickets have been crammed, are distended to bursting-point. A new
ration cannot therefore tempt its gluttony; and henceforth it thinks
only of making itself a silken tabernacle.

In all, its repast has lasted from ten to twelve days without
cessation. At this period the larva’s length measures from twenty-five
to thirty millimetres [20] and its greatest breadth from five to six.
[21] Its general outline, spreading a little at the back and gradually
tapering in front, conforms with the usual type of Hymenopteron-grubs.
Its segments are fourteen in number, including the head, which is very
small and armed with weak mandibles that would appear unequal to the
part which they have just played. Of these fourteen segments the middle
ones are supplied with stigmata, or breathing-holes. Its livery
consists of a yellowish-white ground, studded with innumerable dots of
a chalky white.

We have seen the larva begin its second Cricket with the belly, the
juiciest and softest part. Like a child, which first licks the jam off
its bread and then bites into the crumb with a disdainful tooth, the
larva makes straight for the best part, the abdominal viscera, and
leaves until later the meat that has to be patiently extracted from its
horny sheath: a task for a leisure hour, when it is comfortably
digesting the earlier meal. Nevertheless, the grub, when quite young,
when newly hatched, is not so dainty: it goes for the bread first and
the jam afterwards. It has no choice: it is obliged to bite its first
mouthful right out of the breast, at the spot where the mother fixed
the egg. The food here is a little harder, but the place is safe,
because of the profound inertia into which the thorax has been plunged
by three thrusts of the dagger. Elsewhere there would be, if not
always, at least often, spasmodic shudders which would dislodge the
feeble grub and expose it to terrible hazards among a heap of victims
whose hind-legs, toothed like saws, might give an occasional jerk and
whose mandibles might still be capable of snapping. It is therefore the
question of safety and not of the grub’s likes or dislikes that
determines the mother’s choice in placing the egg.

And here a suspicion occurs to my mind. The first ration, the Cricket
on whom the egg is laid, exposes the grub to more parlous risks than do
the others. To begin with, the larva is still but a frail worm; and
then the victim is quite a recent one and therefore most likely to give
evidence of a spark of life. This first victim has to be paralysed as
completely as possible: consequently it receives the Wasp’s three
dagger-thrusts. But the others, whose torpor deepens the older they
grow, the others whom the larva attacks after it has gained in
strength: do they need to be operated on as carefully? Might not one
prick be enough, or two pricks, the effects of which would spread
little by little while the grub is consuming its first ration? The
poison-fluid is too precious for the Wasp to lavish it unnecessarily:
it is hunting-ammunition, to be employed with due economy. At any rate,
though I have witnessed three consecutive stabs given to the same
victim, at other times I have seen only two administered. It is true
that the quivering tip of the Sphex’ abdomen seemed to be seeking the
favourable spot for a third wound; but, if it was really given, it
escaped me. I should therefore be inclined to think that the victim
forming the first ration is always stabbed thrice, whereas the others,
from motives of economy, receive only two stings. Our study of the
Ammophilæ, who hunt Caterpillars, will confirm this suspicion later.

After devouring the last Cricket the larva sets about weaving its
cocoon. The work is finished well within forty-eight hours. Henceforth
the skilful worker, safe within her impenetrable shelter, can yield to
the irresistible lethargy that invades her, to that nameless mode of
existence, neither sleep nor waking, neither death nor life, from which
she will emerge, ten months from now, transfigured. Very few cocoons
are so complicated as hers. It consists, in fact, in addition to a
coarse outer network, of three distinct layers, presenting the
appearance of three cocoons one inside the other. Let us examine in
detail these several courses of the silken edifice.

There is first an open woof, of a rough cobweb texture, whereon the
larva begins by isolating itself, hanging as in a hammock, to work more
easily at the cocoon proper. This unfinished net, hastily woven to
serve as a builder’s scaffolding, is made of threads flung out at
random, which hold together grains of sand, bits of earth and the
leavings of the larva’s feast: the Cricket’s thighs, still braided with
red, his shanks and pieces of his skull. The next covering, which is
the first covering of the cocoon proper, consists of a much-creased
felted tunic, light-red in colour, very fine and very flexible. A few
threads flung out here and there join it to the previous scaffolding
and to the second wrapper. It forms a cylindrical wallet, closed on
every side and too large for its contents, thus causing the surface to
wrinkle.

Next comes an elastic sheath, distinctly smaller than the wallet that
contains it, almost cylindrical, rounded at the upper end, towards
which the larva’s head is turned, and finishing in a blunt cone at the
lower end. Its colour is still light-red, save towards the cone at the
bottom, where the shade is darker. Its consistency is pretty firm;
nevertheless, it yields to moderate squeezing, except in its conical
part, which resists the pressure of the fingers and seems to contain a
hard substance. On opening this sheath, we see that it is formed of two
layers closely applied one to the other, but easily separated. The
outer layer is a silk felt, exactly like that of the wallet which comes
before; the inner layer, the third layer of the cocoon, is a sort of
shellac, a shiny wash of a dark violet-brown, brittle, very soft to the
touch, and of a nature apparently quite different from the rest of the
cocoon. We see, in fact, under the microscope that, instead of being a
felt of silky threads like the previous wrapper, it is a homogeneous
coating of a peculiar varnish, whose origin is rather singular, as we
shall see. As for the resistance of the cone-shaped end of the cocoon,
we discover that this is due to a plug of crumbly matter, violet-black
and sparkling with a number of black particles. This plug is the dried
mass of the excrement which the larva ejects, once and for all, inside
the cocoon itself. The same stercoral kernel also causes the darker
shade of the cone-shaped end of the cocoon. The complicated dwelling
averages twenty-seven millimetres in length, while its greatest width
is nine millimetres. [22]

Let us return to the violet varnish that lines the inside of the
cocoon. I thought at first that I must attribute it to the silk-glands,
which, after giving a glossy coat to the double wrapper of silk and the
scaffolding, have still a secret store of the fluid. To convince
myself, I opened some larvæ which had just finished their work as
weavers and had not yet begun to apply their lacquer. At that period I
saw no trace of violet fluid in the silk-glands. This shade is found
only in the digestive canal, which bulges with a purple-coloured pulp;
we find it also, but later, in the stercoral plug relegated to the
lower end of the cocoon. With this exception, everything is white, or
faintly tinged with yellow. Far be it from me to suggest that the larva
plasters its cocoon with its excreta; and yet I am convinced that this
plaster is a product of the digestive organs and I suspect, though I
cannot say for certain—having been clumsy enough several times to miss
a favourable opportunity of making sure—that the larva disgorges and
applies with its mouth the quintessence of the purple pulp from its
stomach in order to form the shellac glaze. Only after this last
performance would it reject its digestive residuum in a single lump;
and this would explain the unpleasant necessity in which the larva
finds itself of making room for its excreta inside its actual
habitation.

Be this as it may, there can be no doubt about the usefulness of the
coating of shellac; its complete impermeability must protect the larva
against the damp which would certainly attack it in the precarious
refuge dug for it by the mother. Remember that the larva is buried only
a few inches down in uncovered, sandy ground. To judge to what extent
the cocoons thus varnished are able to resist the damp, I kept some
steeped in water for several days on end, without afterwards finding a
trace of moisture inside them. Compare the Sphex’ cocoon, with its
manifold linings, which are so well adapted for the protection of the
larva in an unprotected burrow, with the cocoon of the Great Cerceris,
lying under the dry shelter of a slab of sandstone and at a distance of
eighteen or twenty inches underground: this cocoon has the shape of a
very long pear, with the narrow end lopped off. It consists of a single
silken wrapper, so thin and fine that the larva shows through it. In my
numerous entomological investigations I have always seen the larva’s
industry and the mother’s thus making good each other’s deficiencies.
In a deep, well-sheltered abode, the cocoon is of a light material; in
a surface dwelling, exposed to the inclemencies of the weather, the
cocoon is stoutly built.

Nine months elapse, during which a task is performed wherein all is
mystery. I skip this period, filled with the dead secret of the
transformation, and, to come to the nymph, pass at once from the end of
September to the first days of the following June. The larva has cast
its withered slough; the nymph, that transitory organism, or rather
that perfect insect in swaddling-bands, motionlessly awaits the
awakening which will not take place for another month to come. The
legs, the antennæ, the exposed mouth-parts and the wing-stumps have the
appearance of clearest crystal and lie evenly spread under the thorax
and the abdomen. The rest of the body is an opaque white, very faintly
smeared with yellow. The middle four segments of the abdomen carry a
narrow and blunt extension on either side. The last segment,
terminating above in a blade-like expansion shaped like the sector of a
circle, is equipped below with two conical protuberances set side by
side: this makes in all eleven appendages studding the outline of the
abdomen. Such is the delicate creature which, to become a Sphex, must
don a motley livery of black and red and throw off the fine skin in
which it is closely swathed.

I was curious to follow from day to day the appearance and the progress
of the nymph’s colouring and to test whether the light of the sun, that
rich palette whence nature derives her colours, could influence that
progress. With this object, I took pupæ from their cocoons and put them
in glass tubes, of which some, kept in complete darkness, realized the
natural conditions of the nymphs and served me as a standard of
comparison, while the others, hung against a white wall, received a
strong diffused light throughout the day. Under these diametrically
opposed conditions, the evolution of the colours remained absolutely
uniform in both cases, or, if there were some slight discrepancies,
these were to the disadvantage of the pupæ exposed to the light. It is,
therefore, exactly the reverse of what happens in the case of plants:
light does not affect the colouring of insects, does not even
accelerate the process; and this must be so, because, in the species
which are the most brilliant in colouring, the Buprestes and
Ground-beetles, for instance, the wondrous hues which one would imagine
to be stolen from a sunbeam are really elaborated in the dusky bowels
of the earth or deep down in the decaying trunk of some venerable tree.

The first outlines of colour show on the eyes, whose faceted cornea
changes successively from white to fawn, next to slate-grey, lastly to
black. The simple eyes at the top of the forehead, the ocelli, share in
this colouring, in their turn, before the rest of the body has yet lost
any of its neutral, white tint. It should be remarked that this early
development of the most delicate organ, the eye, is general in all
animals. Later, a smoky line appears on the upper part of the groove
separating the mesothorax and the metathorax; and, twenty-four hours
later, the whole back of the metathorax is black. At the same time, the
edge of the prothorax becomes shaded, a black dot appears in the
central and upper part of the metathorax, and the mandibles assume a
rusty tinge. Gradually a deeper and deeper shade creeps over the two
end segments of the thorax and finally reaches the head and the
hind-quarters. A day is enough to turn the smoky hue of the head and of
the end segments deep black. Thereupon the abdomen begins to share in
the rapidly-increasing coloration. The edge of its front segments is
tinted saffron; and its hinder segments acquire a dull-black border.
Lastly, the antennæ and legs, after passing through darker and darker
shades, turn black; the lower part of the abdomen is now entirely
orange-red and the tip black. The livery is complete except for the
tarsi and the mouth-parts, which are a transparent red, and the
wing-stumps, which are dull black. In four-and-twenty hours the nymph
will burst its fetters.

It takes the nymph only six or seven days to don its final tints,
omitting the eyes, whose colouring precedes that of the rest of the
body by fourteen or fifteen days. The law governing the insect’s
chromatic evolution is easily gathered from this brief sketch. We see
that, with the exception of the eyes and the ocelli, whose early
development recalls what takes place in the higher animals, the
starting-point of the coloration is a central spot, the mesothorax,
whence it gradually invades, by centrifugal progression, first the rest
of the thorax, then the head and abdomen, lastly the different
appendages, the legs and antennæ. The tarsi and the mouth-parts colour
later still; and the wings do not assume their hue until after they are
taken from their cases.

We now have the Sphex arrayed in her livery. She has yet to cast her
nymphal wrapper. This is a very fine tunic, moulded exactly in
accordance with the smallest structural details and scarcely veiling
the shape and colours of the perfect insect. As a prelude to the last
act of the metamorphosis, the Sphex, suddenly shaking off her torpor,
begins to move about violently, as though to call her long-numbed limbs
to life. The abdomen is alternately lengthened and shortened; the legs
are abruptly extended, then bent, then extended again; and their
different joints are stiffened with an effort. The insect, using its
head and the tip of its abdomen as a lever, with the ventral surface
underneath, repeatedly distends with vigorous jerks the joint of the
neck and that of the peduncle connecting the abdomen and the thorax. At
last its efforts are crowned with success; and, after a quarter of an
hour of these rough gymnastics, the scabbard, tugged in every
direction, rips open at the neck, at the point where the legs are
attached and near the peduncle of the abdomen, in short, wherever the
mobility of the parts has permitted any violent dislocation to take
place.

All these rents in the veil that is being cast result in a number of
irregular shreds, whereof the largest envelops the abdomen and runs up
the back of the thorax. To this shred belong the wing-cases. A second
shred covers the head. Lastly, each leg has its own sheath, more or
less badly treated near the base. The large shred, which in itself
forms the best part of the wrapper, is thrown off by means of alternate
contractions and expansions of the abdomen. By this mechanical process
it is slowly forced backwards, where it ends by forming a little pellet
that for some time remains fastened to the insect by the tracheal
gills. The Sphex then once more becomes motionless; and the operation
is over. However, the head, antennæ and legs are still more or less
veiled. It is evident that the legs in particular cannot be freed all
in one piece, because of the numerous excrescences or spines with which
they are armed. These different shreds of skin dry up on the insect and
are removed afterwards by rubbing the legs. It is not until the Sphex
has acquired her full vigour that she finishes her moulting by
brushing, smoothing and combing her whole body with her tarsi.

The way in which the wings come out of their sheaths is the most
remarkable part of the sloughing. In their incomplete stump stage they
are folded lengthwise and are very much compressed. It is easy to
extract them from their cases a little while before the normal date of
their appearance; but then they remain permanently contracted and do
not fill out. On the other hand, when once the large strip of skin to
which the sheaths of the wings belong is pushed back by the movements
of the abdomen, we see the wings come slowly out of their cases and
straightway, as they become free, assume dimensions out of all
proportion to the narrow prison whence they emerge. They are therefore
the seat of an abundant rush of vital fluids which swell them and
spread them out, and which, owing to the inflation which they provoke,
must be the chief cause of the wings’ emergence from their cases. When
newly expanded, the wings are heavy, full of juices and of a very pale
straw-colour. If the rush of the fluids takes place irregularly, we
then see the end of the wing weighed down by a little yellow drop
contained between the two scales.

After stripping herself of the abdominal sheath, which carries the
wing-cases with it, the Sphex relapses into immobility for about three
days. During this time the wings assume their normal hue, the tarsi
become coloured, and the mouth-parts, at first extended, adopt their
proper position. After twenty-four days spent in the nymphal stage, the
insect has achieved the perfect state. It tears the cocoon that holds
it captive, opens itself a passage through the sand and comes out one
fine morning into the light of day, undazzled by that hitherto unknown
radiance. Bathed in sunshine, the Sphex brushes her antennæ and her
wings, passes and repasses her legs over her abdomen, washes her eyes
with her front tarsi wetted with saliva, like a cat; and, her toilet
finished, flies away joyfully: she has two months to live.

You pretty Sphex-wasps hatched before my eyes, brought up by my hand,
ration by ration, on a bed of sand in an old quill-box; you whose
transformations I have followed step by step, starting up from my sleep
in alarm lest I should have missed the moment when the nymph is
bursting its swaddling-bands or the wing leaving its case; you who have
taught me so much and learned nothing yourselves, knowing without
teachers all that you have to know: O my pretty Sphex-wasps, fly away
without fear of my tubes, my boxes, my bottles, or any of my
receptacles, through this warm sunlight beloved of the Cicadæ; [23] go,
but beware of the Praying Mantis, [24] who is plotting your ruin on the
flowering heads of the thistles, and mind the Lizard, who is lying in
wait for you on the sunny slopes; go in peace, dig your burrows, stab
your Crickets scientifically and continue your kind, to procure one day
for others what you have given me: the few moments of happiness in my
life!



CHAPTER VII

ADVANCED THEORIES


The species of the genus Sphex are fairly numerous, but are for the
most part strangers to my country. As far as I know, the French fauna
numbers only three, all lovers of the hot sun of the olive district,
namely, the Yellow-winged Sphex (Sphex flavipennis), the White-edged
Sphex (S. albisecta), and the Languedocian Sphex (S. occitanica). Now
it is not without a lively interest that the observer notices in the
case of these three freebooters a choice of provisions which is in
strict accordance with the rigid laws of entomological classification.
To feed their grubs, all three choose solely Orthoptera. [25] The first
hunts Crickets, the second Locusts, the third Ephippigers.

The prey selected have such great outward differences one from the
other that to associate them and grasp their similarity calls for the
practised eye of the entomologist or the no less experienced eye of the
Sphex. Pray compare the Cricket with the Locust: the first has a large,
round, stumpy head, is short and thickset and black all over, with red
stripes on his hinder thighs; the second is greyish in colour, long and
slim, with a small, tapering head, leaps forward by suddenly unbending
his long hind-legs and continues this flight with wings furled like a
fan. Next compare both of these with the Ephippiger, who carries his
musical instrument, two shrill cymbals shaped like concave scales, on
his back and who waddles along with his pendulous belly, ringed
pale-green and buttercup-yellow and armed with a long dirk. Place the
three side by side and you will agree with me that, to guide her in
choosing between such dissimilar species, while still keeping to the
same entomological order, the Sphex must have an eye so expert that no
man—not your ordinary layman, but a man of science—need be ashamed to
own it.

In the face of these singular predilections, which seem to have had
their limits laid down for them by some master of classification, by a
Latreille, for instance, it becomes interesting to investigate whether
the Sphex-wasps that are not natives of our country hunt game of the
same order. Unfortunately, information on this point is scanty and, in
the case of most of the species, is lacking altogether. The chief cause
of this regrettable lacuna is the superficial method generally adopted.
People catch an insect, stick a long pin through it, fix it in the
cork-bottomed box, gum a label with a Latin name underneath its feet,
and let its history end there. It is not thus that I understand the
duties of an entomological biographer. It is no use telling me that
this or that species has so many joints to its antennæ, so many
nervures to its wings, so many hairs on a region of the belly or
thorax; I do not really know the insect until I am acquainted with its
manner of life, its instincts and its habits.

And see the immense and luminous advantage which a description of this
kind, told in two or three words, would possess over those long
descriptive details, sometimes so hard to grasp. Suppose that you wish
to make the Languedocian Sphex known to me and you begin by describing
the number and distribution of the nervures of the wings; you speak to
me of cubital nervures and recurrent nervures. Next comes the insect’s
pen-portrait. Black here, rusty red there, smoky brown at the tips of
the wings; black velvet in this part, silvery down in that, a smooth
surface in a third. It is all very definite and minute: we must do this
much justice to the precision and patience of the narrator; but it is
very long and also it is by no means always clear, so much so that we
may be excused if we are not quite able to follow it, even when we are
not altogether new to the business. But add to the tedious description
merely this: ‘Hunts Ephippigers’; and these two words at once shed
light: there is no possibility of my now mistaking my Sphex, for she
alone possesses the monopoly of that particular prey. To give this
illuminating note, what would be needed? The habit of really observing
and of not making entomology consist of so many series of impaled
insects.

But let us pass on and examine the little that is known about the
hunting methods of the foreign Sphex-wasps. I open Lepeletier de
Saint-Fargeau’s [26] Natural History of Hymenoptera and find that, on
the other side of the Mediterranean, in our Algerian provinces, the
Yellow-winged Sphex and the White-edged Sphex retain the same habits
that characterize them here. They capture Orthoptera in the land of
palm-trees even as they do in the land of olive-trees. Though separated
from the others by the vast width of the sea, the hunting compatriots
of the Kabyles and the Berbers pursue the same game as their kindred in
Provence. I also see that a fourth species, the African Sphex (S.
afra), is the scourge of the Locusts in the neighbourhood of Oran.
Lastly, I remember reading, I forget where, of a fifth species which
also wages war on Locusts in the steppes near the Caspian. Thus, on the
borders of the Mediterranean, we have five different species of Sphex,
whose larvæ all live on a diet of Orthoptera.

Now let us cross the equator and go right down to the southern
hemisphere, to the islands of Mauritius and Réunion: we shall here find
not a Sphex, but a closely-allied Wasp of the same tribe, the
Compressed Chlorion, hunting the horrible Kakerlak, that ravager of the
foodstuffs in the ships and harbours of the colonies. These Kakerlaks
are none other than Cockroaches, whereof one species haunts our
dwellings. Who does not know the evil-smelling insect, which, thanks to
its flat body, like that of a huge Bug, slips at night through the gaps
in furniture and the crannies of partitions and invades any place
containing provisions to be devoured? This is the Black-beetle of our
houses, a disgusting counterpart of the no less disgusting prey beloved
of the Chlorion. What is there about the Kakerlak to cause him to be
selected as a prey by a near cousin of our Sphex-wasps? It is quite
simple: with his Bug shape, the Kakerlak also is an Orthopteron, just
as much as the Cricket, the Ephippiger or the Locust. From these six
examples, the only ones known to me and of such different origins, we
might perhaps deduce that all the Sphex hunt Orthoptera. At any rate,
without adopting so general a conclusion, we see what the food of their
larvæ must be in most cases.

There is a reason for this surprising choice. What is it? What are the
grounds for a diet which, within the strict limits of one entomological
order, is composed here of stinking Kakerlaks, there of somewhat dry,
but highly-flavoured Locusts, elsewhere again of plump Crickets or fat
Ephippigers? I confess that I cannot tell, that I am absolutely in the
dark; and I leave the problem to others. At the same time, we may
observe that the Orthoptera are among insects what the Ruminants are
among mammals. Endowed with a mighty paunch and a placid temperament,
they graze contentedly and soon put on flesh. They are numerous, widely
distributed and slow in movement, which renders them easy to catch;
moreover, they are of a large size, making fine heads of game. Who can
say if the Sphex-wasps, powerful huntresses, requiring big prey, do not
find in these Ruminants of the insect world what we ourselves find in
our domestic Ruminants, the Sheep and the Ox, peaceable victims
yielding plenty of flesh? It is just a possibility, but no more.

I have something better than a possibility to offer in reply to another
and no less important question. Do the Orthopteron-eaters ever vary
their diet? Should the favourite type of game fall short, can they not
accept a different one? Does the Languedocian Sphex consider that there
is nothing in the world worth having but fat Ephippigers? Does the
White-edged Sphex allow none but Locusts to figure on her table; and
the Yellow-winged Sphex none but Crickets? Or, according to time, place
and circumstances, does each make up for the lack of her favourite
victuals by others more or less equivalent? To ascertain such facts, if
they exist, would be of the greatest importance, for they would tell us
if the inspirations of instinct are absolute and unchangeable, or if
they vary and within what limits. It is true that the cells of one and
the same Cerceris contain the most varied species of either the
Buprestis or the Weevil group, which shows that the huntress has a
great latitude of choice; but this extension of the hunting-fields
cannot be presumed in the case of the Sphex-wasps, whom I have seen so
faithful to an exclusive victim, always the same for each of them, and
who moreover find, among the Orthoptera, groups that differ very widely
in shape. Nevertheless, I have had the good fortune to come upon one
case, one only, of complete change in the larva’s nourishment; and I
record it the more willingly in the Sphegian archives inasmuch as such
facts, scrupulously observed, will one day form foundation-stones for
any one who cares to build up the psychology of instinct on a solid
basis.

Here are the facts. The scene is enacted on a towing-path along the
Rhône. On one side is the mighty stream, with its roaring waters; on
the other is a thick hedge of osiers, willows, and reeds; between the
two runs a narrow walk, with a carpet of fine sand. A Yellow-winged
Sphex appears, hopping along, dragging her prey. What do I see! The
prey is not a Cricket, but a common Acridian, a Locust! And yet the
Wasp is really the Sphex with whom I am so familiar, the Yellow-winged
Sphex, the keen Cricket-huntress. I can hardly believe the evidence of
my own eyes.

The burrow is not far off: the insect enters it and stores away the
booty. I sit down, determined to wait for a new expedition, to wait
hours if necessary, so that I may see if the extraordinary capture is
repeated. My sitting attitude makes me take up the whole width of the
path. Two raw conscripts heave in sight, their hair newly cut, wearing
that inimitable automaton look which the first days of barrack-life
bestow. They are chatting together, talking no doubt of home and the
girl they left behind them; and each is innocently whittling a
willow-switch with his knife. I am seized with a sudden apprehension.
Ah, it is no easy matter to experiment on the public road, where, when
the long-awaited event occurs at last, the arrival of a wayfarer is
likely to disturb or ruin opportunities that may never return! I rise,
anxiously, to make way for the conscripts; I stand back in the
osier-bed and leave the narrow passage free. To do more would have been
unwise. To say, ‘Don’t go this way, my good lads,’ would have made bad
worse. They would have suspected some trap hidden under the sand,
giving rise to questions to which no reply that I could have made would
have sounded satisfactory. Besides, my request would have turned those
idlers into lookers-on, very embarrassing company in such studies. I
therefore got up without speaking and trusted to my lucky star. Alas
and alack, my star betrayed me: the heavy regulation boot came straight
down upon the ceiling of the Sphex! A shudder ran through me as though
I myself had received the impress of the hobnailed sole.

When the conscripts had passed, I proceeded to save what I could of the
ruined burrow’s contents. The Sphex was there, crushed and mangled; and
with her not only the Locust whom I had seen carried down, but two
others as well, making three Locusts in all instead of the usual
Crickets. What was the reason of this curious change? Were there no
Crickets in the neighbourhood of the burrow and was the distressed Wasp
making up for them with Locusts: a case of Hobson’s choice, in fact? I
hesitate to believe it, for there was nothing about the neighbourhood
to warrant the supposition that the favourite game was absent. Another,
luckier than I, will unriddle this new and unknown mystery. The fact
remains that the Yellow-winged Sphex, either from imperious necessity
or for some reason that escapes me, sometimes replaces her chosen prey,
the Cricket, with another prey, the Locust, presenting no external
resemblance to the first, but itself also an Orthopteron.

The observer on whose authority Lepeletier de Saint-Fargeau says a word
or two touching the habits of this same Sphex witnessed a similar
storing away of Locusts in Africa, near Oran. He surprised a
Yellow-winged Sphex dragging an Acridian along. Was it an accidental
case, like that which I witnessed on the banks of the Rhône? Was it an
exception or the rule? Can there be a lack of Crickets in the country
around Oran and does the Wasp fill their place with Acridians? The
force of circumstances compels me to put the question without finding a
reply.

This is the place to interpolate a certain passage from Lacordaire’s
[27] Introduction to Entomology against which I am eager to protest.
Here it is:


    ‘Darwin, [28] who wrote a book on purpose to prove the identity of
    the intellectual principle actuating men and animals, was walking
    one day in his garden when he saw on the path a Sphex who had just
    possessed herself of a Fly almost as large as herself. He saw her
    cut off the victim’s head and abdomen with her mandibles, keeping
    only the thorax, to which the wings remained attached, after which
    she flew away; but a breath of wind, striking the Fly’s wings, made
    the Sphex spin round and prevented her progress; hereupon she
    alighted again on the path, cut off one of the Fly’s wings and then
    the other, and, after thus destroying the cause of her
    difficulties, resumed her flight with what remained of her prey.
    This fact carries with it manifest signs of reasoning power.
    Instinct might have led this Sphex to cut off her victim’s wings
    before carrying it to her nest, as do some species of the same
    genus; but here there was a sequence of ideas and results from
    those ideas, which are quite inexplicable unless we allow the
    intervention of reason.’


This little story, which so lightly grants reason to an insect, lacks I
will not say truth, but even mere likelihood, not in the act itself,
which I accept without reserve, but in the motives for the act. Darwin
saw what he tells us; only, he was mistaken as to the heroine of the
drama, the drama itself and its significance. He was profoundly
mistaken; and I will prove it.

First of all, the old English scientist was bound to know enough about
the creatures to which he gives these high dignities to call things by
their right names. Let us therefore take the word Sphex in its strict
scientific meaning. Under this assumption, by what strange aberration
was this English Sphex, if any such there be, choosing a Fly for her
prey, when her kinswomen hunt such different game, Orthoptera? Even
admitting what I consider to be inadmissible, a Fly to form the quarry
of a Sphex, other difficulties come crowding up. It is now duly proved
that the Burrowing Wasps do not take dead bodies to their larvæ, but a
victim merely numbed, paralysed. Then what is the meaning of this prey
of which the Sphex cuts off the head, the abdomen, the wings? The stump
carried away is no more than a fragment of a corpse, which would infect
the cell with its rottenness, without being of any use to the larva,
whose hatching is not due for some days yet. It is as clear as
daylight: when making his observation, Darwin did not have before him a
Sphex in the strict sense of the word. Then what did he see?

The term Fly, by which the captured prey is designated, is a very
elastic word, which can be applied to the immense order of Diptera and
which therefore leaves us undecided among thousands of species. The
expression Sphex is most likely also employed in an equally indefinite
sense. At the end of the eighteenth century, when Darwin’s book
appeared, this expression was used to denote not only the Sphegidæ
proper, but particularly the Crabronidæ. Now, among the latter, some,
when storing provisions for their larvæ, hunt Diptera, Flies, the prey
required by the unknown Hymenopteron of the English naturalist. Then
was Darwin’s Sphex a Crabro? No; for these Dipteron-hunters, like the
hunters of any other prey, want game that keeps fresh, motionless but
half-alive, for the fortnight or three weeks required for the hatching
of the eggs and the complete development of the larvæ. All these little
ogres need meat killed that day and not gone bad or even a little high.
This is a rule to which I know of no exception. The word Sphex cannot
be accepted therefore, even with its old meaning.

Instead of a precise fact, really worthy of science, we have a riddle
to read. Let us continue to examine the riddle. Different species of
the Crabro family are so like the Social Wasps in size, in shape and in
their black-and-yellow livery as to deceive any eye unversed in the
delicate distinctions of entomology. To any one who has not made a
special study of such subjects a Crabro is a Common Wasp. May it not
have happened that the English observer, looking at things from a
height and thinking unworthy of strict investigation the tiny fact
which nevertheless was to corroborate his transcendental theories and
help to bestow reason upon an animal, made a mistake in his turn, but
one in the other direction and quite pardonable, by taking a Wasp for a
Crabro? I would almost dare swear so; and here are my reasons.

Wasps, if not always, at least often bring up their family on animal
food; but, instead of accumulating a provision of game in each cell
beforehand, they distribute the food to the larvæ, one by one and
several times a day; they feed them with their mouths, as the father
and mother feed young birds with their beaks. And the mouthful consists
of a fine mash of chewed insects, ground between the mandibles of the
Wasp nurse. The favourite insects for the preparation of this infants’
food are Diptera, especially Common Flies; when fresh meat can be had,
it is a windfall eagerly turned to account. Who has not seen Wasps
boldly enter our kitchens or pounce upon the meat hanging in the
butchers’ shops, to cut off a scrap that suits them and carry it away
forthwith, as spolia opima for the use of the grubs? When the
half-closed shutters admit a streak of sunlight to the floor of a room,
where the Housefly is taking a luxurious nap or polishing her wings,
who has not seen the Wasp rush in, swoop down upon the Fly, crush her
in her mandibles and make off with the booty? Once again, a morsel
reserved for the carnivorous nurselings.

The prey is dismembered now on the spot where captured, now on the way,
now at the nest. The wings, which possess no nutritive value, are cut
off and rejected; the legs, which are poor in juices, are also
sometimes disdained. There remains a mutilated corpse, head, thorax,
abdomen, united or separated, which the Wasp chews and rechews to
reduce it to the pap beloved of the larvæ. I have tried to take the
place of the nurses in this method of rearing grubs on Fly-soup. The
subject of my experiment was a nest of Polistes gallica, the Wasp who
fastens her little rosette of brown-paper cells to the roots of a
shrub. My kitchen-table was a flat piece of marble on which I crushed
the Fly-pap after cleaning the heads of game, that is to say, after
removing the parts that were too tough, the wings and legs; lastly, the
feeding-spoon was a fine straw, at the tip of which the dish was
served, from cell to cell, to each nurseling, which opened its
mandibles just as the young birds in the nest might do. I used to go to
work in exactly the same way and succeeded no better when bringing up
broods of Sparrows, that joy of my childhood. All went well as long as
my patience did not fail me, tried as it was by the cares of so finikin
and absorbing an education.

The obscurity of the enigma gives way to the full light of truth thanks
to the following observation, made with all the deliberateness which
strict precision calls for. In the early days of October, two large
clumps of asters in blossom outside the door of my study became the
meeting-place of a host of insects, among which the Hive-bee and an
Eristalis-fly (Eristalis tenax) predominate. A gentle murmur rose from
them, like that of which Virgil sings:


        Sæpe levi somnum suadebit inire susurro. [29]


But, where the poet finds but an incitement to the delights of sleep,
the naturalist beholds a subject for study: all this small folk making
holiday on the last flowers of the year will perhaps furnish him with
some fresh data. Behold me then on observation duty before the two
clumps with their thousands of lilac petals.

The air is absolutely still, the sun blazing, the atmosphere heavy:
signs of an approaching storm, but conditions eminently favourable to
the work of the Hymenoptera, who seem to foresee to-morrow’s rain and
redouble their activity to improve the opportunity. And so the Bees
plunder eagerly, while the Eristales fly clumsily from flower to
flower. At times, the peaceable multitude, filling its crop with
nectar, is disturbed by the sudden invasion of the Wasp, a ravening
insect attracted hither by prey, not honey.

Equally ardent in carnage, but very unequal in strength, two species
divide the hunting between them: the Common Wasp (Vespa vulgaris), who
catches Eristales, and the Hornet (Vespa crabro), who preys on
Hive-bees. The methods are the same in either case. Both bandits
explore the expanse of flowers with an impetuous flight, going
backwards and forwards in a thousand directions, and then make a sudden
rush for the coveted prey, which is on its guard and flies away, while
the kidnapper’s impetus brings her up with a bump against the deserted
flower. Then the pursuit continues in the air, as though a Sparrow-hawk
were chasing a Lark. But the Bee and the Eristalis, by taking brisk
turns, soon baffle the attempts of the Wasp, who resumes her evolutions
above the clustering blossoms. At last, sooner or later, some quarry
less quick at flight is captured. Forthwith, the Common Wasp drops on
to the lawn with her Eristalis; I also instantly lie on the ground,
quietly removing with my hands the dead leaves and bits of grass that
might interfere with my view; and I witness the following tragedy, if I
have taken proper precautions not to scare the huntress.

First, there is a wild struggle in the tangle of the grass between the
Wasp and the Eristalis, who is bigger than her assailant. The Fly is
unarmed, but powerful; a shrill buzz of her wings tells of her
desperate resistance. The Wasp carries a dagger; but she does not
understand the methodical use of it, is unacquainted with the
vulnerable points so well known to the marauders who need a prey that
keeps fresh for long. What her nurselings want is a mess of Flies that
moment reduced to pulp; and, so long as this is achieved, the Wasp
cares little how the game is killed. The sting therefore is used
blindly, without any method. We see it pointed indifferently at the
victim’s back, sides, head, thorax, or belly, according to the chances
of the scuffle. The Hunting Wasp paralysing her victim acts like a
surgeon who directs his scalpel with a skilled hand; the Social Wasp
killing her prey behaves like a common assassin who stabs at random.
For this reason the Eristalis’ resistance is prolonged; and her death
is the result of scissor-cuts rather than dagger-thrusts. When the
victim is duly garrotted, motionless between its ravisher’s legs, the
head falls under a snap of the mandibles; then the wings are cut off at
their juncture with the shoulder; the legs follow, severed one by one;
lastly, the belly is flung aside, but emptied of the entrails, which
the Wasp appears to add to the one favoured portion. This choice morsel
is solely the thorax, which is richer in lean meat than the rest of the
Eristalis’ body. Without further delay the Wasp flies off with it,
carrying it in her legs. On reaching the nest, she will make it into
potted Fly and serve it in mouthfuls to the larvæ.

The Hornet who has caught a Bee acts in much the same manner; but, in
the case of an assailant of her dimensions, the struggle cannot last
long, notwithstanding the victim’s sting. The Hornet may prepare her
dish on the very flower where the capture was effected, or more often
on some twig of an adjacent shrub. The Bee’s crop is first ripped open
and the honey that runs out of it lapped up. The prize is thus a
twofold one: a drop of honey for the huntress to feast upon and the Bee
herself for the larvæ. Sometimes the wings are removed and also the
abdomen; but generally the Hornet is satisfied with reducing the Bee to
a shapeless mass, which she carries off without disdaining anything.
Those parts which have no nutritive value, especially the wings, will
be rejected on arriving at the nest. Lastly, she sometimes prepares the
mash in the actual hunting-field, that is to say, she crushes the Bee
between her mandibles after removing the wings, the legs, and at times
the abdomen as well.

Here then, in all its details, is the incident observed by Darwin. A
Wasp (Vespa vulgaris) catches a big Fly (Eristalis tenax); she cuts off
the victim’s head, wings, abdomen, and legs with her mandibles and
keeps only the thorax, which she carries off flying. But here there is
not the least breath of wind to explain the carving process; besides,
the thing happens in a perfect shelter, in the thick tangle of the
grass. The butcher rejects such parts of her prey as she considers
valueless to her larvæ; and that is all about it.

In short, the heroine of Darwin’s story is certainly a Wasp. Then what
becomes of that rational calculation on the part of the insect which,
the better to contend with the wind, cuts off its prey’s abdomen, head
and wings and keeps only the thorax? It becomes a most simple incident,
leading to none of the mighty consequences which the writer seeks to
deduce from it: the very trivial incident of a Wasp who begins to carve
up her prey on the spot and keeps only the stump, the one part which
she considers fit for her larvæ. Far from seeing the least sign of
reason in this, I look upon it as a mere act of instinct, one so
elementary that it is really not worth expatiating upon.

To disparage man and exalt animals in order to establish a point of
contact, followed by a point of union, has been and still is the
general tendency of the ‘advanced theories’ in fashion in our day. Ah,
how often are these ‘sublime theories,’ that morbid craze of the time,
based upon ‘proofs’ which, if subjected to the light of experiment,
would lead to as ridiculous results as the learned Erasmus Darwin’s
Sphex!



CHAPTER VIII

THE LANGUEDOCIAN SPHEX


When the chemist has fully prepared his plan of research, he mixes his
reagent at the most convenient moment and lights a flame under his
retort. He is the master of time, place and circumstances. He chooses
his hour, shuts himself up in his laboratory, where nothing can come to
disturb the business in hand; he produces at will this or that
condition which reflection suggests to him: he is in quest of the
secrets of inorganic matter, whose chemical activities science can
awaken whenever it thinks fit.

The secrets of living matter—not those of anatomical structure, but
really those of life in action, especially of instinct—present much
more difficult and delicate conditions to the observer. Far from being
able to choose his own time, he is the slave of the season, of the day,
of the hour, of the very moment. When the opportunity offers, he must
seize it as it comes, without hesitation, for it may be long before it
presents itself again. And, as it usually arrives at the moment when he
is least expecting it, nothing is in readiness for making the most of
it. He must then and there improvise his little stock of experimenting
material, contrive his plans, evolve his tactics, devise his tricks;
and he can think himself lucky if inspiration comes fast enough to
allow him to profit by the chance offered. This chance, moreover,
hardly ever comes except to those who look for it. You must watch for
it patiently for days and days, now on sandy slopes exposed to the full
glare of the sun, now on some path walled in by high banks, where the
heat is like that of an oven, or again on some sandstone ledge which is
none too steady. If it is in your power to set up your observatory
under a meagre olive-tree that pretends to protect you from the rays of
a pitiless sun, you may bless the fate that treats you as a sybarite:
your lot is an Eden. Above all, keep your eyes open. The spot is a good
one; and—who knows?—the opportunity may come at any moment.

It came—late, it is true; but still it came. Ah, if you could now
observe at your ease, in the quiet of your study, with nothing to
distract your mind from your subject, far from the profane wayfarer
who, seeing you so busily occupied at a spot where he sees nothing,
will stop, overwhelm you with queries, take you for some water-diviner,
or—a graver suspicion this—regard you as some questionable character
searching for buried treasure and discovering by means of incantations
where the old pots full of coin lie hidden! Should you still wear a
Christian aspect in his eyes, he will approach you, look to see what
you are looking at, and smile in a manner that leaves no doubt as to
his poor opinion of people who spend their time in watching Flies. You
will be lucky indeed if the troublesome visitor, with his tongue in his
cheek, walks off at last without disturbing things and without
repeating in his innocence the disaster brought about by my two
conscripts’ boots.

Should your inexplicable doings not puzzle the passer-by, they will be
sure to puzzle the village keeper, that uncompromising representative
of the law in the ploughed acres. He has long had his eye on you. He
has so often seen you wandering about, like a lost soul, for no
appreciable reason; he has so often caught you rooting in the ground,
or, with infinite precautions, knocking down some strip of wall in a
sunken road, that in the end he has come to look upon you with dark
suspicion. You are nothing to him but a gipsy, a tramp, a
poultry-thief, a shady person or, at the best, a madman. Should you be
carrying your botanizing-case, it will represent to him the poacher’s
ferret-cage; and you would never get it out of his head that,
regardless of the game-laws and the rights of landlords, you are
clearing all the neighbouring warrens of their rabbits. Take care.
However thirsty you may be, do not lay a finger on the nearest bunch of
grapes: the man with the municipal badge will be there, delighted to
have a case at last and so to receive an explanation of your highly
perplexing behaviour.

I have never, I can safely say, committed any such misdemeanour; and
yet, one day, lying on the sand, absorbed in the details of a Bembex’
household, I suddenly heard beside me:

‘In the name of the law, I arrest you! You come along with me!’

It was the keeper of Les Angles, who, after vainly waiting for an
opportunity to catch me at fault and being daily more anxious for an
answer to the riddle that was worrying him, at last resolved upon the
brutal expedient of a summons. I had to explain things. The poor man
seemed anything but convinced:

‘Pooh!’ he said. ‘Pooh! You will never make me believe that you come
here and roast in the sun just to watch Flies. I shall keep an eye on
you, mark you! And, the first time I...! However, that’ll do for the
present.’

And he went off. I have always believed that my red ribbon had a good
deal to do with his departure. And I also put down to that red ribbon
certain other little services by which I benefited during my
entomological and botanical excursions. It seemed to me—or was I
dreaming?—it seemed to me that, on my botanizing expeditions up Mont
Ventoux, the guide was more tractable and the donkey less obstinate.

The aforesaid bit of scarlet ribbon did not always spare me the
tribulations which the entomologist must expect when experimenting on
the public way. Here is a characteristic example. Ever since daybreak I
have been ambushed, sitting on a stone, at the bottom of a ravine. The
subject of my matutinal visit is the Languedocian Sphex. Three women,
vine-pickers, pass in a group, on the way to their work. They give a
glance at the man seated, apparently absorbed in reflection. At sunset,
the same pickers pass again, carrying their full baskets on their
heads. The man is still there, sitting on the same stone, with his eyes
fixed on the same place. My motionless attitude, my long persistency in
remaining at that deserted spot, must have impressed them deeply. As
they passed by me, I saw one of them tap her forehead and heard her
whisper to the others:

‘Un paouré inoucènt, pécaïre!’

And all three made the sign of the Cross.

An innocent, she had said, un inoucènt, an idiot, a poor creature,
quite harmless, but half-witted; and they had all made the sign of the
Cross, an idiot being to them one with God’s seal stamped upon him.

‘How now!’ thought I. ‘What a cruel mockery of fate! You, who are so
laboriously seeking to discover what is instinct in the animal and what
is reason, you yourself do not even possess your reason in these good
women’s eyes! What a humiliating reflection!’

No matter: pécaïre, that expression of supreme compassion, in the
Provençal dialect, pécaïre, coming from the bottom of the heart, soon
made me forget inoucènt.

It is in this ravine with its three grape-gathering women that I would
meet the reader, if he be not discouraged by the petty annoyances of
which I have given him a foretaste. The Languedocian Sphex frequents
these points, not in tribes congregating at the same spot when
nest-building work begins, but as solitary individuals, sparsely
distributed, settling wherever the chances of their vagabondage lead
them. Even as her kinswoman, the Yellow-winged Sphex, seeks the society
of her kind and the animation of a yard full of workers, the
Languedocian Sphex prefers isolation, quiet and solitude. Graver of
gait, more formal in her manners, of a larger size and also more
sombrely clad, she always lives apart, not caring what others do,
disdaining company, a genuine misanthrope among the Sphegidæ. The one
is sociable, the other is not: a profound difference which in itself is
enough to characterize them.

This amounts to saying that, with the Languedocian Sphex, the
difficulties of observation increase. No long-meditated experiment is
possible in her case; nor, when the first attempts have failed, can one
hope to try them again, on the same occasion, with a second or a third
subject and so on. If you prepare the materials for your observation in
advance, if, for instance, you have in reserve a piece of game which
you propose to substitute for that of the Sphex, it is to be feared,
nay, it is almost certain that the huntress will not appear; and, when
she does come at last, your materials are no longer fit for use and
everything has to be improvised in a hurry, that very moment, under
conditions that are not always satisfactory.

Let us take heart. The site is a first-rate one. Many a time already I
have surprised the Sphex here, sunning herself on a vine-leaf. The
insect, spread out flat, is basking voluptuously in the heat and light.
From time to time it has a sort of frenzied outburst of pleasure: it
quivers with content; it rapidly taps its feet on its couch, producing
a tattoo not unlike that of rain falling heavily on the leaf. The
joyous thrum can be heard several feet away. Then immobility begins
again, soon followed by a fresh nervous commotion and by the whirling
of the tarsi, a symbol of supreme felicity. I have known some of these
passionate sun-lovers suddenly to leave the work-yard, when the larva’s
cave has been half-dug, and go to the nearest vine to take a bath of
heat and light, after which they would come back to the burrow, as
though reluctantly, just to give a perfunctory sweep and soon end by
knocking off work, unable to resist the exquisite temptation of
luxuriating on the vine-leaves.

It may be that the voluptuous couch is also an observatory, whence the
Wasp surveys the surrounding country in order to discover and select
her prey. Her exclusive game is the Ephippiger of the Vine, scattered
here and there on the branches or on any brambles hard by. The joint is
a substantial one, especially as the Sphex favours solely the females,
whose bellies are swollen with a mighty cluster of eggs.

Let us take no notice of the repeated trips, the fruitless searches,
the tedium of frequent long waiting, but rather present the Sphex
suddenly to the reader as she herself appears to the observer. Here she
is, at the bottom of a sunken road with high, sandy banks. She comes on
foot, but gets help from her wings in dragging her heavy prize. The
Ephippiger’s antennæ, long and slender as threads, are the
harnessing-ropes. Holding her head high, she grasps one of them in her
mandibles. The antenna gripped passes between her legs; and the game
follows, turned over on its back. Should the soil be too uneven and so
offer resistance to this method of carting, the Wasp clasps her
unwieldy burden and carries it with very short flights, interspersed,
as often as possible, with journeys on foot. We never see her undertake
a sustained flight, for long distances, holding the game in her legs,
as is the practice of those expert aviators, the Bembeces and Cerceres,
for instance, who bear through the air for more than half a mile their
respective Flies or Weevils, a very light booty compared with the huge
Ephippiger. The overpowering weight of her capture compels the
Languedocian Sphex to make the whole, or nearly the whole, journey on
foot, her method of transport being consequently slow and laborious.

The same reason, the bulk and weight of the prey, have entirely
reversed the usual order which the Burrowing Wasps follow in their
operations. This order we know: it consists in first digging a burrow
and then stocking it with provisions. As the victim is not out of
proportion to the strength of the spoiler, it is quite simple to carry
it flying, which means that the Wasp can choose any site that she likes
for her dwelling. She does not mind how far afield she goes for her
prey: once she has captured her quarry, she comes flying home at a
speed which makes questions of distance quite immaterial. Hence she
prefers as the site for her burrow the place where she herself was
born, the place where her forbears lived; she here inherits deep
galleries, the accumulated work of earlier generations; and, by
repairing them a little, she makes them serve as approaches to new
chambers, which are in this way better protected than they would be if
they depended upon the labours of a single Wasp, who had to start
boring from the surface each year. This happens, for instance, in the
case of the Great Cerceris and the Bee-eating Philanthus. And, should
the ancestral abode not be strong enough to withstand the rough weather
from one year to the next and to be handed down to the offspring,
should the burrower have each time to start her tunnelling afresh, at
least the Wasp finds greater safety in places consecrated by the
experience of her forerunners. Consequently she goes there to dig her
galleries, each of which serves as a corridor to a group of cells, thus
effecting an economy in the aggregate labour expended upon the whole
business of the laying.

In this way are formed not real societies, for there are no concerted
efforts towards a common object, but at least assemblies where the
sight of her kinswomen and her neighbours doubtless puts heart into the
labour of the individual. We can observe, in fact, between these little
tribes, springing from the same stock, and the burrowers who do their
work alone, a difference in activity which reminds us of the emulation
prevailing in a crowded yard and the indifference of labourers who have
to work in solitude. Action is contagious in animals as in men; it is
fired by its own example.

To sum up: when of a moderate weight for its captor, the prey can be
conveyed flying, to a great distance. The Wasp can then choose any site
that she pleases for her burrow. She adopts by preference the spot
where she was born and uses each passage as a common corridor giving
access to several cells. The result of this meeting at a common
birthplace is the formation of groups, like turning to like, which is a
source of friendly rivalry. This first step towards social life comes
from facilities for travelling. Do not things happen in the same way
with man, if I may be permitted the comparison? When he has nothing but
trackless paths, man builds a solitary hut; when supplied with good
roads, he and his fellows collect in populous cities; when served by
railways which, so to speak, annihilate distance, they assemble in
those immense human hives called London or Paris.

The situation of the Languedocian Sphex is just the reverse. Her prey
is a heavy Ephippiger, a single dish representing by itself the sum
total of provisions which the other freebooters amass on numerous
journeys, insect by insect. What the Cerceres and the other plunderers
strong on the wing accomplish by dividing the labour she does in a
single journey. The weight of the prey makes any distant flight
impossible; it has to be brought home slowly and laboriously, for it is
a troublesome business to cart things along the ground. This alone
makes the site of the burrow dependent on the accidents of the chase:
the prey comes first and the dwelling next. So there is no assembling
at a common meeting-place, no association of kindred spirits, no tribes
stimulating one another in their work by mutual example, but isolation
in the particular spot where the chances of the day have taken the
Sphex, solitary labour, carried on without animation though with
unfailing diligence. First of all, the prey is sought for, attacked,
reduced to helplessness. Not until after that does the digger trouble
about the burrow. A favourable place is chosen, as near as possible to
the spot where the victim lies, so as to cut short the tedious work of
transport; and the chamber of the future larva is rapidly hollowed out
and at once receives the egg and the victuals. There you have an
example of the inverted method of the Languedocian Sphex, a method, as
all my observations go to prove, diametrically opposite to that of the
other Hymenoptera. I will give some of the more striking of these
observations.

When caught digging, the Languedocian Sphex is always alone, sometimes
at the bottom of a dusty recess left by a stone that has dropped out of
an old wall, sometimes ensconced in the shelter formed by a flat,
projecting bit of sandstone, a shelter much sought after by the fierce
Eyed Lizard to serve as an entrance-hall to his lair. The sun beats
full upon it; it is an oven. The soil, consisting of old dust that has
fallen little by little from the roof, is very easy to dig. The cell is
soon scooped out with the mandibles, those pincers which are also used
for digging, and the tarsi, which serve as rubbish-rakes. Then the
miner flies off, but with a slow flight and no sudden display of
wing-power, a manifest sign that the insect is not contemplating a
distant expedition. We can easily follow it with our eyes and perceive
the spot where it alights, usually ten or twelve yards away. At other
times it decides to walk. It goes off and makes hurriedly for a spot
where we will have the indiscretion to follow it, for our presence does
not trouble it at all. On reaching its destination, either on foot or
on the wing, it looks round for some time, as we gather from its
undecided attitude and its journeys hither and thither. It looks round;
at last it finds or rather retrieves something. The object recovered is
an Ephippiger, half-paralysed, but still moving her tarsi, antennæ and
ovipositor. She is a victim which the Sphex certainly stabbed not long
ago with a few stings. After the operation the Wasp left her prey, an
embarrassing burden amid the suspense of house-hunting; she abandoned
it perhaps on the very spot where she captured it, contenting herself
with making it more or less conspicuous by placing it on some
grass-tuft, in order to find it more easily later; and, trusting to her
good memory to return presently to the spot where the booty lies, she
set out to explore the neighbourhood with the object of finding a
suitable site and there digging a burrow. Once the home was ready, she
came back to her prize, which she found again without much hesitation,
and she now prepares to lug it home. She bestrides the victim, seizes
one or both of the antennæ, and off she goes, tugging and dragging with
all the strength of her loins and jaws.

Sometimes she has only to make one journey; at other times and more
often, the carter suddenly plumps down her load and quickly runs home.
Perhaps it occurs to her that the entrance-door is not wide enough to
admit so substantial a morsel; perhaps she remembers some lack of
finish that might hamper the storing. And, in point of fact, the worker
does touch up her work: she enlarges the doorway, smooths the
threshold, strengthens the ceiling. It is all done with a few strokes
of the tarsi. Then she returns to the Ephippiger, lying yonder, on her
back, a few steps away. The hauling begins again. On the road, the
Sphex seems struck with a new idea, which flashes through her quick
brain. She has inspected the door, but has not looked inside. Who knows
if all is well in there? She hastens to see, dropping the Ephippiger
before she goes. The interior is inspected; and apparently a few pats
of the trowel are administered with the tarsi, giving a last polish to
the walls. Without lingering too long over these delicate
after-touches, the Wasp goes back to her booty and harnesses herself to
its antennæ. Forward! Will the journey be completed this time? I would
not answer for it. I have known a Sphex, more suspicious than the
others, perhaps, or more neglectful of the minor architectural details,
to repair her omissions, to dispel her doubts, by abandoning her prize
on the way five or six times running, in order to hurry to the burrow,
which each time was touched up a little or merely inspected within. It
is true that others make straight for their destination, without even
stopping to rest. I must also add that, when the Wasp goes home to
improve the dwelling, she does not fail to give a glance from a
distance every now and then at the Ephippiger over there, to make sure
that nothing has happened to her. This solicitude recalls that of the
Sacred Beetle when he leaves the hall which he is excavating in order
to come and feel his beloved pellet and bring it a little nearer to
him.

The inference to be drawn from the details which I have related is
manifest. The fact that every Languedocian Sphex surprised in her
mining operations, even though it be at the very beginning of the
digging, at the first stroke of the tarsus in the dust, afterwards,
when the home is prepared, makes a short excursion, now on foot, anon
flying, and invariably finds herself in possession of a victim already
stabbed, already paralysed, compels us to conclude, in all certainty,
that this Wasp does her work as a huntress first and as a burrower
after, so that the place of the capture decides the place of the home.

This reversal of procedure, which causes the food to be prepared before
the larder, whereas hitherto we have seen the larder come before the
food, I attribute to the weight of the Sphex’ prey, a prey which it is
not possible to carry far through the air. It is not that the
Languedocian Sphex is ill-built for flight: on the contrary, she can
soar magnificently; but the prey which she hunts would weigh her down
if she had no other support than her wings. She needs the support of
the ground for her hauling-work, in which she displays wonderful
strength. When laden with her prey, she always goes afoot, or takes but
very short flights, even under conditions when flight would save her
time and trouble. I will quote an instance taken from my latest
observations on this curious Wasp.

A Sphex appears unexpectedly, coming I know not whence. She is on foot,
dragging her Ephippiger, a capture which apparently she has made that
moment in the neighbourhood. In the circumstances it behoves her to dig
herself a burrow. The site is as bad as bad can be. It is a well-beaten
path, hard as stone. The Sphex, who has no time to make laborious
excavations, because the already captured prize must be stored as
quickly as possible, the Sphex wants soft ground, wherein the larva’s
chamber can be contrived in one short spell of work. I have described
her favourite soil, namely, the dust of years which has accumulated at
the bottom of some hole in a wall or of some little shelter under the
rocks. Well, the Sphex whom I am now observing stops at the foot of a
house with a newly-whitewashed front some twenty to twenty-five feet
high. Her instinct tells her that up there, under the red tiles of the
roof, she will find nooks rich in old dust. She leaves her prey at the
foot of the house and flies up to the roof. For some time I see her
looking here, there, and everywhere. After finding a proper site, she
begins to work under the curve of a pantile. In ten minutes, or fifteen
at most, the home is ready. The insect now flies down again. The
Ephippiger is promptly found. She has to be taken up. Will this be done
on the wing, as circumstances seem to demand? Not at all. The Sphex
adopts the toilsome method of scaling a perpendicular wall, with a
surface smoothed by the mason’s trowel and measuring twenty to
twenty-five feet in height. Seeing her take this road, dragging the
game between her legs, I at first think the feat impossible; but I am
soon reassured as to the outcome of the bold attempt. Getting a
foothold on the little roughnesses in the mortar, the plucky insect,
despite the hindrance of her heavy load, walks up this vertical plane
with the same assured gait and the same speed as on level ground. The
top is reached without the least accident; and the prey is laid
temporarily on the edge of the roof, upon the rounded back of a tile.
While the digger gives a finishing touch to the burrow, the
badly-balanced prey slips and drops to the foot of the wall. The thing
must be done all over again and once more by laboriously climbing the
height. The same mistake is repeated. Again the prey is incautiously
left on the curved tile, again it slips and again it falls to the
ground. With a composure which accidents such as these cannot disturb,
the Sphex for the third time hoists up the Ephippiger by scaling the
wall and, better advised, drags her forthwith right into the home.

As even under these conditions no attempt has been made to carry the
prey on the wing, it is clear that the Wasp is incapable of long flight
with so heavy a load. To this incapacity we owe the few characteristics
that form the subject of this chapter. A quarry that is not too big to
permit the effort of flying makes of the Yellow-winged Sphex a
semisocial species, that is to say, one seeking the company of her
fellows; a quarry too heavy to carry through the air makes of the
Languedocian Sphex a species vowed to solitary labour, a sort of savage
disdainful of the pleasures that come from the proximity of one’s kind.
The lighter or heavier weight of the game selected here determines the
fundamental character of the huntress.



CHAPTER IX

THE WISDOM OF INSTINCT


To paralyse her prey, the Languedocian Sphex, I have no doubt, pursues
the method of the Cricket-huntress and drives her lancet repeatedly
into the Ephippiger’s breast in order to strike the ganglia of the
thorax. The process of wounding the nerve-centres must be familiar to
her; and I am convinced beforehand of her consummate skill in that
scientific operation. This is an art thoroughly known to all the
Hunting Wasps, who carry a poisoned dart that has not been given them
in vain. At the same time, I must confess that I have never yet
succeeded in witnessing the deadly performance. This omission is due to
the solitary life led by the Languedocian Sphex.

When a number of burrows are dug on a common site and then provisioned,
one has but to wait on the spot to see now one huntress and now another
arrive with the game which they have caught. It is easy in these
circumstances to try upon the new arrivals the substitution of a live
prey for the doomed victim and to repeat the experiment as often as we
wish. Besides, the certainty that we shall not lack subjects of
observation, as and when wanted, enables us to arrange everything in
advance. With the Languedocian Sphex these conditions of success do not
exist. To set out expressly to look for her, with one’s material
prepared, is almost useless, as the solitary insect is scattered one by
one over vast expanses of ground. Moreover, if you do come upon her, it
will most often be in an idle hour and you will get nothing out of her.
As I said before, it is nearly always unexpectedly, when your thoughts
are elsewhere engaged, that the Sphex appears, dragging her Ephippiger
after her.

This is the moment, the only propitious moment, to attempt a
substitution of prey and invite the huntress to let you witness her
lancet-thrusts. Quick, let us procure an alternative morsel, a live
Ephippiger! Hurry, time presses: in a few minutes the burrow will have
received the victuals and the glorious occasion will be lost! Must I
speak of my mortification at these moments of good fortune, the mocking
bait held out by chance? Here, before my eyes, is matter for
interesting observations; and I cannot profit by it! I cannot surprise
the Sphex’ secret for the lack of something to offer her in the place
of her prize! Try it for yourself, try setting out in quest of an
alternative piece with only a few minutes at your disposal, when it
took me three days of wild running about before I found Weevils for my
Cerceres! And yet I made the desperate experiment twice over. Ah, if
the keeper had caught me this time, tearing like mad through the
vineyards, what a good opportunity it would have been for crediting me
with robbery and having me up before the magistrate! Vine-branches and
clusters of grapes: not a thing did I respect in my mad rush, hampered
by the trailing shoots. I must have an Ephippiger at all costs, I must
have him that moment. And once I did get my Ephippiger during one of
these frenzied expeditions. I was radiant with joy, never suspecting
the bitter disappointment in store for me.

If only I arrive in time, if only the Sphex be still engaged in
transport work! Thank heaven, everything is in my favour! The Wasp is
still some distance away from her burrow and still dragging her prize
along. With my forceps I pull gently at it from behind. The huntress
resists, stubbornly clutches the antennæ of her victim and refuses to
let go. I pull harder, even drawing the carter back as well; it makes
no difference: the Sphex does not loose her hold. I have with me a pair
of sharp scissors, belonging to my little entomological case. I use
them and promptly cut the harness-ropes, the Ephippiger’s long antennæ.
The Sphex continues to move ahead, but soon stops, astonished at the
sudden decrease in the weight of the burden which she is trailing, for
this burden is now reduced merely to the two antennæ, snipped off by my
mischievous wiles. The real load, the heavy, pot-bellied insect,
remains behind and is instantly replaced by my live specimen. The Wasp
turns round, lets go the ropes that now draw nothing after them, and
retraces her steps. She comes face to face with the prey substituted
for her own. She examines it, walks round it gingerly, then stops,
moistens her foot with saliva, and begins to wash her eyes. In this
attitude of meditation, can some such thought as the following pass
through her mind:

‘Come now! Am I awake or am I asleep? Do I know what I am about or do I
not? That thing’s not mine. Who or what is trying to humbug me?’

At any rate, the Sphex shows no great hurry to attack my prey with her
mandibles. She keeps away from it and shows not the smallest wish to
seize it. To excite her, I offer the insect to her in my fingers, I
almost thrust the antennæ under her teeth. I know that she does not
suffer from shyness; I know that she will come and take from your
fingers, without hesitation, the prey which you have snatched from her
and afterwards present to her. But what is this? Scorning my offers,
the Sphex retreats instead of snapping up what I place within her
reach. I put down the Ephippiger, who, obeying a thoughtless impulse,
unconscious of danger, goes straight to his assassin. Now we shall see!
Alas, no: the Sphex continues to recoil, like a regular coward, and
ends by flying away. I never saw her again. Thus ended, to my
confusion, an experiment that had filled me with such enthusiasm.

Later and by degrees, as I inspected an increasing number of burrows, I
came to understand my failure and the obstinate refusal of the Sphex. I
always found the provisions to consist, without a single exception, of
a female Ephippiger, harbouring in her belly a copious and succulent
cluster of eggs. This appears to be the favourite food of the grubs.
Well, in my hurried rush through the vines, I had laid my hands on an
Ephippiger of the other sex. I was offering the Sphex a male. More
far-seeing than I in this important question of provender, the Wasp
would have nothing to say to my game:

‘A male, indeed! Is that a dinner for my larvæ? What do you take them
for?’

What nice discrimination they have, these dainty epicures, who are able
to differentiate between the tender flesh of the female and the
comparatively dry flesh of the males! What an unerring glance, which
can distinguish at once between the two sexes, so much alike in shape
and colour! The female carries a sword at the tip of her abdomen, the
ovipositor wherewith the eggs are buried in the ground; and that is
about the only external difference between her and the male. This
distinguishing feature never escapes the perspicacious Sphex; and that
is why, in my experiment, the Wasp rubbed her eyes, hugely puzzled at
beholding swordless a prey which she well knew carried a sword when she
caught it. What must not have passed through her little Sphex brain at
the sight of this transformation?

Let us now watch the Wasp when, having prepared the burrow, she goes
back for her victim, which, after its capture and the operation that
paralysed it, she has left at no great distance. The Ephippiger is in a
condition similar to that of the Cricket sacrificed by the
Yellow-winged Sphex, a condition proving for certain that stings have
been driven into her thoracic ganglia. Nevertheless, a good many
movements still continue; but they are disconnected, though endowed
with a certain vigour. Incapable of standing on its legs, the insect
lies on its side or on its back. It flutters its long antennæ and also
its palpi; it opens and closes its mandibles and bites as hard as in
the normal state. The abdomen heaves rapidly and deeply. The ovipositor
is brought back sharply under the belly, against which it almost lies
flat. The legs stir, but languidly and irregularly; the middle legs
seem more torpid than the others. If pricked with a needle, the whole
body shudders convulsively; efforts are made to get up and walk, but
without success. In short, the insect would be full of life, but for
its inability to move about or even to stand upon its legs. We have
here therefore a wholly local paralysis, a paralysis of the legs, or
rather a partial abolition and ataxy of their movements. Can this very
incomplete inertia be caused by some special arrangement of the
victim’s nervous system, or does it come from this, that the Wasp
perhaps administers only a single prick, instead of stinging each
ganglion of the thorax, as the Cricket-huntress does? I cannot tell.

Still, for all its shivering, its convulsions, its disconnected
movements, the victim is none the less incapable of hurting the larva
that is meant to devour it. I have taken from the burrow of the Sphex
Ephippigers struggling just as lustily as when they were first
half-paralysed; and nevertheless the feeble grub, hatched but a few
hours since, was digging its teeth into the gigantic victim in all
security; the dwarf was biting into the colossus without danger to
itself. This striking result is due to the spot selected by the mother
for laying her egg. I have already said how the Yellow-winged Sphex
glues her egg to the Cricket’s breast, a little to one side, between
the first and second pair of legs. Exactly the same place is chosen by
the White-edged Sphex; and a similar place, a little farther back,
towards the root of one of the large hind-thighs, is adopted by the
Languedocian Sphex, all three thus giving proof, by this uniformity, of
wonderful discernment in picking out the spot where the egg is bound to
be safe.

Consider the Ephippiger pent in the burrow. She lies stretched upon her
back, absolutely incapable of turning. In vain she struggles, in vain
she writhes: the disordered movements of her legs are lost in space,
the room being too wide to afford them the support of its walls. The
grub cares nothing for the victim’s convulsions: it is at a spot where
naught can reach it, not tarsi, nor mandibles, nor ovipositor, nor
antennæ; a spot absolutely stationary, devoid of so much as a surface
tremor. It is in perfect safety, on the sole condition that the
Ephippiger cannot shift her position, turn over, get upon her feet; and
this one condition is admirably fulfilled.

But, with several heads of game, all in the same stage of paralysis,
the larva’s danger would be great. Though it would have nothing to fear
from the insect first attacked, because of its position out of the
reach of its victim, it would have every occasion to dread the
proximity of the others, which, stretching their legs at random, might
strike it and rip it open with their spurs. This is perhaps the reason
why the Yellow-winged Sphex, who heaps up three or four Crickets in the
same cell, practically annihilates all movement in its victims, whereas
the Languedocian Sphex, victualling each burrow with a single piece of
game, leaves her Ephippigers the best part of their power of motion and
contents herself with making it impossible for them to change their
position or stand upon their legs. She may thus, though I cannot say so
positively, economize her dagger-thrusts.

While the only half-paralysed Ephippiger cannot imperil the larva,
fixed on a part of the body where resistance is impossible, the case is
different with the Sphex, who has to cart her prize home. First, having
still, to a great extent, preserved the use of its tarsi, the victim
clutches with these at any blade of grass encountered on the road along
which it is being dragged; and this produces an obstacle to the hauling
process which is difficult to overcome. The Sphex, already heavily
burdened by the weight of her load, is liable to exhaust herself with
her efforts to make the other insect relax its desperate grip in grassy
places. But this is the least serious drawback. The Ephippiger
preserves the complete use of her mandibles, which snap and bite with
their customary vigour. Now what these terrible nippers have in front
of them is just the slender body of the enemy, at a time when she is in
her hauling attitude. The antennæ, in fact, are grasped not far from
their roots, so that the mouth of the victim dragged along on its back
faces either the thorax or the abdomen of the Sphex, who, standing high
on her long legs, takes good care, I am convinced, not to be caught in
the mandibles yawning underneath her. At all events, a moment of
forgetfulness, a slip, the merest trifle can bring her within the reach
of two powerful nippers, which would not neglect the opportunity of
taking a pitiless vengeance. In the more difficult cases at any rate,
if not always, the action of those formidable pincers must be done away
with; and the fish-hooks of the legs must be rendered incapable of
increasing their resistance to the process of transport.

How will the Sphex go to work to obtain this result? Here man, even the
man of science, would hesitate, would waste his time in barren efforts
and would perhaps abandon all hope of success. He can come and take one
lesson from the Sphex. She, without ever being taught it, without ever
seeing it practised by others, understands her surgery through and
through. She knows the most delicate mysteries of the physiology of the
nerves, or rather she behaves as if she did. She knows that under her
victim’s skull there is a circlet of nervous nuclei, something similar
to the brain of the higher animals. She knows that this main centre of
innervation controls the action of the mouth-parts and moreover is the
seat of the will, without whose orders not a single muscle acts;
lastly, she knows that, by injuring this sort of brain, she will cause
all resistance to cease, the insect no longer possessing any will to
resist. As for the mode of operating, this is the easiest matter in the
world to her; and, when we have been taught in her school, we are free
to try her process in our turn. The instrument employed is no longer
the sting: the insect, in its wisdom, has deemed compression preferable
to a poisoned thrust. Let us accept its decision, for we shall see
presently how prudent it is to be convinced of our own ignorance in the
presence of the animal’s knowledge. Lest by editing my account I should
fail to give a true impression of the sublime talent of this masterly
operator, I here copy out my note as I pencilled it on the spot,
immediately after the stirring spectacle.

The Sphex finds that her victim is offering too much resistance,
hooking itself here and there to blades of grass. She then stops to
perform upon it the following curious operation, a sort of coup de
grâce. The Wasp, still astride her prey, forces open the articulation
of the neck, high up, at the nape. Then she seizes the neck with her
mandibles and, without making any external wound, probes as far forward
as possible under the skull, so as to seize and chew up the ganglia of
the head. When this operation is done, the victim is utterly
motionless, incapable of the least resistance, whereas previously the
legs, though deprived of the power of connected movement needed for
walking, vigorously opposed the process of traction.

There is the fact in all its eloquence. With the points of its
mandibles, the insect, while leaving uninjured the thin and supple
membrane of the neck, goes rummaging into the skull and munching the
brain. There is no effusion of blood, no wound, but simply an external
pressure. Of course, I kept for my own purposes the Ephippiger
paralysed before my eyes, in order to ascertain the effects of the
operation at my leisure; also, of course, I hastened to repeat in my
turn, upon live Ephippigers, what the Sphex had just taught me. I will
here compare my results with the Wasp’s.

Two Ephippigers whose cervical ganglia I squeeze and compress with a
forceps fall rapidly into a state resembling that of the victims of the
Sphex. Only, they grate their cymbals if I tease them with a needle;
and the legs still retain a few disordered and languid movements. The
difference no doubt is due to the fact that my patients were not
previously injured in their thoracic ganglia, as were those of the
Sphex, who were first stung on the breast. Allowing for this important
condition, we see that I was none too bad a pupil and that I imitated
pretty closely my teacher of physiology, the Sphex. I confess it was
not without a certain satisfaction that I succeeded in doing almost as
well as the insect.

As well? What am I talking about? Wait a bit and you shall see that I
still have much to learn from the Sphex. For what happens is that my
two patients very soon die: I mean, they really die; and, in four or
five days, I have nothing but putrid corpses before my eyes. And the
Wasp’s Ephippiger? I need hardly say that the Wasp’s Ephippiger, even
ten days after the operation, is perfectly fresh, just as she will be
required by the larva for which she has been destined. Nay, more: only
a few hours after the operation under the skull, there reappeared, as
though nothing had occurred, the disorderly movements of the legs,
antennæ, palpi, ovipositor and mandibles; in a word, the insect
returned to the condition wherein it was before the Sphex bit its
brain. And these movements were kept up after, though they became
feebler every day. The Sphex had merely reduced her victim to a passing
state of torpor, lasting amply long enough to enable her to bring it
home without resistance; and I, who thought myself her rival, was but a
clumsy and barbarous butcher: I killed my prize. She, with her
inimitable dexterity, shrewdly compressed the brain to produce a
lethargy of a few hours; I, brutal through ignorance, perhaps crushed
under my forceps that delicate organ, the main seat of life. If
anything could prevent me from blushing at my defeat, it would be the
conviction that very few, if any, could vie with these clever ones in
cleverness.

Ah, I now understand why the Sphex does not use her sting to injure the
cervical ganglia! A drop of poison injected here, at the centre of
vital force, would destroy the whole nervous system; and death would
follow soon after. But it is not death that the huntress wishes to
obtain; the larvæ have not the least use for dead game, for a corpse,
in short, smelling of corruption; and all that she wants to bring about
is a lethargy, a passing torpor, which will put a stop to the victim’s
resistance during the carting process, this resistance being difficult
to overcome and moreover dangerous for the Sphex. The torpor is
obtained by a method known in laboratories of experimental physiology:
compression of the brain. The Sphex acts like a Flourens, [30] who,
laying bare an animal’s brain and bearing upon the cerebral mass,
forthwith suppresses intelligence, will, sensibility and movement. The
pressure is removed; and everything reappears. Even so do the remains
of the Ephippiger’s life reappear, as the lethargic effects of a
skilfully-directed pressure pass off. The ganglia of the skull,
squeezed between the mandibles but without fatal contusions, gradually
recover their activity and put an end to the general torpor. Admit that
it is all alarmingly scientific.



Fortune has her entomological whims: you run after her and catch no
glimpse of her; you forget about her and behold, she comes tapping at
your door! How vainly I watched and waited, how many useless journeys I
made to see the Languedocian Sphex sacrifice her Ephippigers! Twenty
years pass; these pages are in the printer’s hands; and, one day early
this month, on the 8th of August 1878, my son Emile comes rushing into
my study:

‘Quick!’ he shouts. ‘Come quick: there’s a Sphex dragging her prey
under the plane-trees, outside the door of the yard!’

Emile knew all about the business, from what I had told him, to amuse
him when we used to sit up late, and better still from similar
incidents which he had witnessed in our life out of doors. He is right.
I run out and see a magnificent Languedocian Sphex dragging a paralysed
Ephippiger by the antennæ. She is making for the hen-house close by and
seems anxious to scale the wall, with the object of fixing her burrow
under some tile on the roof; for, a few years ago, in the same place, I
saw a Sphex of the same species accomplish the ascent with her game and
make her home under the arch of a badly-joined tile. Perhaps the
present Wasp is descended from the one who performed that arduous
climb.

A like feat seems about to be repeated; and this time before numerous
witnesses, for all the family, working under the shade of the
plane-trees, come and form a circle around the Sphex. They wonder at
the unceremonious boldness of the insect, which is not diverted from
its work by a gallery of onlookers; all are struck by its proud and
lusty bearing, as, with raised head and the victim’s antennæ firmly
gripped in its mandibles, it drags the enormous burden after it. I,
alone among the spectators, feel a twinge of regret at the sight:

‘Ah, if only I had some live Ephippigers!’ I cannot help saying, with
not the least hope of seeing my wish realized.

‘Live Ephippigers?’ replies Émile. ‘Why, I have some perfectly fresh
ones, caught this morning!’

He dashes upstairs, four steps at a time, and runs to his little den,
where a fence of dictionaries encloses a park for the rearing of some
fine caterpillars of the Spurge Hawk-moth. He brings me three
Ephippigers, the best that I could wish for, two females and a male.

How did these insects come to be at hand, at the moment when they were
wanted, for an experiment tried in vain twenty years ago? That is
another story. A Lesser Grey Shrike had nested in one of the tall
plane-trees of the avenue. Now a few days earlier, the mistral, the
brutal north-west wind of our parts, blew with such violence as to bend
the branches as well as the reeds; and the nest, turned upside down by
the swaying of its support, had dropped its contents, four small birds.
Next morning I found the brood upon the ground; three were killed by
the fall, the fourth was still alive. The survivor was entrusted to the
cares of Émile, who went Cricket-hunting twice a day on the
neighbouring grass-plots for the benefit of his young charge. But
Crickets are small and the nurseling’s appetite called for many of
them. Another dish was preferred, the Ephippiger, of whom a stock was
collected from time to time among the stalks and prickly leaves of the
eryngo. The three insects which Émile brought me came from the Shrike’s
larder. My pity for the fallen nestling had procured me this
unhoped-for success.

After making the circle of spectators stand back so as to leave the
field clear for the Sphex, I take away her prey with a pair of pincers
and at once give her in exchange one of my Ephippigers, carrying a
sword at the end of her belly, like the game which I have abstracted.
The dispossessed Wasp stamps her feet two or three times; and that is
the only sign of impatience which she gives. She goes for her new prey,
which is too stout, too obese even to try to avoid pursuit, grips it
with her mandibles by the saddle-shaped corselet, gets astride and,
curving her abdomen, slips the end of it under the Ephippiger’s thorax.
Here, no doubt, some stings are administered, though I am unable to
state the number exactly, because of the difficulty of observation. The
Ephippiger, a peaceable victim, suffers herself to be operated on
without resistance; she is like the silly Sheep of our
slaughter-houses. The Sphex takes her time and wields her lancet with a
deliberation which favours accuracy of aim. So far, the observer has
nothing to complain of; but the prey touches the ground with its breast
and belly, and exactly what happens underneath escapes his eye. As for
interfering and lifting the Ephippiger a little, so as to see better,
that must not be thought of: the murderess would resheathe her weapon
and retire. The act that follows is easy to observe. After stabbing the
thorax, the tip of the abdomen appears under the victim’s neck, which
the operator forces open by pressing the nape. At this point the sting
probes with marked persistency, as if the prick administered here were
more effective than elsewhere. One would be inclined to think that the
nerve-centre attacked is the lower part of the œsophageal chain; but
the continuance of movement in the mouth-parts—the mandibles, jaws and
palpi—controlled by this seat of innervation shows that such is not the
case. Through the neck the Sphex reaches simply the ganglia of the
thorax, or at any rate the first of them, which is more easily
accessible through the thin skin of the neck than through the
integuments of the chest.

And in a moment it is all over. Without the least shiver denoting pain,
the Ephippiger becomes henceforth an inert mass. I remove the Sphex’
patient for the second time and replace it by the other female at my
disposal. The same proceedings are repeated, followed by the same
result. The Sphex has performed her skilful surgery thrice over, almost
in immediate succession, first with her own prey and then with my
substitutes. Will she do so a fourth time with the male Ephippiger whom
I still have left? I have my doubts, not because the Wasp is tired, but
because the game does not suit her. I have never seen her with any prey
but females, who, crammed with eggs, are the food which the larvæ
appreciate above all others. My suspicion is well founded; deprived of
her capture, the Sphex stubbornly refuses the male whom I offer to her.
She runs hither and thither, with hurried steps, in search of the
vanished game; three or four times she goes up to the Ephippiger, walks
round him, casts a scornful glance at him; and at last she flies away.
He is not what her larvæ want; experiment demonstrates this once again
after an interval of twenty years.

The three females stabbed, two of them before my eyes, remain in my
possession. In each case all the legs are completely paralysed. Whether
lying naturally, on its belly or on its back or side, the insect
retains indefinitely whatever position we give it. A continued
fluttering of the antennæ, a few intermittent pulsations of the belly,
and the play of the mouth-parts are the only signs of life. Movement is
destroyed but not susceptibility; for, at the least prick administered
to a thin-skinned spot, the whole body gives a slight shudder. Perhaps,
some day, physiology will find in such victims the material for
valuable work on the functions of the nervous system. The Wasp’s sting,
so incomparably skilful at striking a particular point and
administering a wound which affects that point alone, will supplement,
with immense advantage, the experimenter’s brutal scalpel, which rips
open where it ought to give merely a light touch. Meanwhile, here are
the results which I have obtained from the three victims, but in
another direction.

As only the movement of the legs has been destroyed, without any wound
save that of the nerve-centres, which are the seat of that movement,
the insect must die of inanition and not of its injuries. The
experiment was conducted as follows: two sound and healthy Ephippigers,
just as I picked them up in the fields, were imprisoned without food,
one in the dark, the other in the light. The second died in four days,
the first in five. This difference of a day is easily explained. In the
light, the insect made greater exertions to recover its liberty; and,
as every movement of the animal machine is accompanied by a
corresponding expenditure of energy, a greater sum total of activity
has involved a more rapid consumption of the reserve force of the
organism. In the light, there is more restlessness and a shorter life;
in the dark, less restlessness and a longer life, while no food at all
was taken in either case.

One of my three stabbed Ephippigers was kept in the dark, fasting. In
her case there were not only the conditions of complete abstinence and
darkness, but also the serious wounds inflicted by the Sphex; and
nevertheless for seventeen days I saw her continually waving her
antennæ. As long as this sort of pendulum keeps on swinging, the clock
of life does not stop. On the eighteenth day the creature ceased its
antennary movements and died. The badly-wounded insect therefore lived,
under the same conditions, four times as long as the insect that was
untouched. What seemed as though it should be a cause of death was
really a cause of life.

However paradoxical it may seem at first sight, this result is
exceedingly simple. When untouched, the insect exerts itself and
consequently uses up its reserves. When paralysed, it has merely the
feeble, internal movements which are inseparable from any organism; and
its substance is economized in proportion to the weakness of the action
displayed. In the first case, the animal machine is at work and wears
itself out; in the second, it is at rest and saves itself. There being
no nourishment now to repair the waste, the moving insect spends its
nutritive reserves in four days and dies; the motionless insect does
not spend them and lives for eighteen days. Life is a continual
dissolution, the physiologists tell us; and the Sphex’ victims give us
the neatest possible demonstration of the fact.

One remark more. Fresh food is absolutely necessary for the Wasp’s
larvæ. If the prey were warehoused in the burrow intact, in four or
five days it would be a corpse abandoned to corruption; and the
scarce-hatched grub would find nothing to live upon but a putrid mass.
Pricked with the sting, however, it can keep alive for two or three
weeks, a period more than long enough to allow the egg to hatch and the
larva to grow. The paralysing of the victim therefore has a twofold
result: first, the living dish remains motionless and the safety of the
delicate grub is not endangered; secondly, the meat keeps good a long
time and thus ensures wholesome food for the larva. Man’s logic,
enlightened by science, could discover nothing better.

My two other Ephippigers stung by the Sphex were kept in the dark with
food. To feed inert insects, hardly differing from corpses except by
the perpetual waving of their long antennæ, seems at first an
impossibility; still, the play of the mouth-parts gave me some hope and
I tried. My success exceeded my anticipations. There was no question
here, of course, of giving them a lettuce-leaf or any other piece of
green stuff on which they might have browsed in their normal state;
they were feeble valetudinarians, who needed spoon-feeding, so to
speak, and supporting with liquid nourishment. I used sugar-and-water.

Laying the insect on its back, I place a drop of the sugary fluid on
its mouth with a straw. The palpi at once begin to stir; the mandibles
and jaws move. The drop is swallowed with evident satisfaction,
especially after a somewhat prolonged fast. I repeat the dose until it
is refused. The meal takes place once a day, sometimes twice, at
irregular intervals, lest I should become too much of a slave to my
patients. Well, one of the Ephippigers lived for twenty-one days on
this meagre fare. It was not much, compared with the eighteen days of
the one whom I had left to die of starvation. True, the insect had
twice had a bad fall, having dropped from the experimenting-table to
the floor owing to some piece of awkwardness on my part. The bruises
which it received must have hastened its end. The other, which suffered
no accidents, lived for forty days. As the nourishment employed,
sugar-and-water, could not indefinitely take the place of the natural
green food, it is very likely that the insect would have lived longer
still if the usual diet had been possible. And so the point which I had
in view is proved: the victims stung by the Digger-wasps die of
starvation and not of their wounds.



CHAPTER X

THE IGNORANCE OF INSTINCT


The Sphex has shown us how infallibly and with what transcendental art
she acts when guided by the unconscious inspiration of her instinct;
she is now going to show us how poor she is in resource, how limited in
intelligence, how illogical even, in circumstances outside of her
regular routine. By a strange inconsistency, characteristic of the
instinctive faculties, profound wisdom is accompanied by an ignorance
no less profound. To instinct nothing is impossible, however great the
difficulty may be. In building her hexagonal cells, with their floors
consisting of three lozenges, the Bee solves with absolute precision
the arduous problem of how to achieve the maximum result at a minimum
cost, a problem whose solution by man would demand a powerful
mathematical mind. The Wasps whose larvæ live on prey display in their
murderous art methods hardly rivalled by those of a man versed in the
intricacies of anatomy and physiology. Nothing is difficult to
instinct, so long as the act is not outside the unvarying cycle of
animal existence; on the other hand, nothing is easy to instinct, if
the act is at all removed from the course usually pursued. The insect
which astounds us, which terrifies us with its extraordinary
intelligence, surprises us, the next moment, with its stupidity, when
confronted with some simple fact that happens to lie outside its
ordinary practice. The Sphex will supply us with a few instances.

Let us follow her dragging her Ephippiger home. If fortune smile upon
us, we may witness some such little scene as that which I will now
describe. When entering her shelter under the rock, where she has made
her burrow, the Sphex finds, perched on a blade of grass, a Praying
Mantis, a carnivorous insect which hides cannibal habits under a pious
appearance. The danger threatened by this robber ambushed on her path
must be known to the Sphex, for she lets go her game and pluckily
rushes upon the Mantis, to inflict some heavy blows and dislodge her,
or at all events to frighten her and inspire her with respect. The
robber does not move, but closes her lethal machinery, the two terrible
saws of the arm and fore-arm. The Sphex goes back to her capture,
harnesses herself to the antennæ and boldly passes under the blade of
grass whereon the other sits perched. By the direction of her head we
can see that she is on her guard and that she holds the enemy rooted,
motionless, under the menace of her eyes. Her courage meets with the
reward which it deserves: the prey is stored away without further
mishap.

A word more on the Praying Mantis, or, as they say in Provence, lou
Prégo Diéou, the Pray-to-God. Her long, pale-green wings, like
spreading veils, her head raised heavenwards, her folded arms, crossed
upon her breast, are in fact a sort of travesty of a nun in ecstasy.
And yet she is a ferocious creature, loving carnage. Though not her
favourite spots, the work-yards of the various Digger-wasps receive her
visits pretty frequently. Posted near the burrows, on some bramble or
other, she waits for chance to bring within her reach some of the
arrivals, forming a double capture for her, as she seizes both the
huntress and her prey. Her patience is long put to the test: the Wasp
suspects something and is on her guard; still, from time to time, a
rash one gets caught. With a sudden rustle of wings half-unfurled as by
the violent release of a clutch, the Mantis terrifies the newcomer, who
hesitates for a moment, in her fright. Then, with the sharpness of a
spring, the toothed fore-arm folds back on the toothed upper arm; and
the insect is caught between the blades of the double saw. It is as
though the jaws of a Wolf-trap were closing on the animal that had
nibbled at its bait. Thereupon, without unloosing the cruel machine,
the Mantis gnaws her victim by small mouthfuls. Such are the ecstasies,
the prayers, the mystic meditations of the Prégo Diéou.

Of the scenes of carnage which the Praying Mantis has left in my
memory, let me relate one. The thing happens in front of a work-yard of
Bee-eating Philanthi. These diggers feed their larvæ on Hive-bees, whom
they catch on the flowers while gathering pollen and honey. If the
Philanthus who has made a capture feels that her Bee is swollen with
honey, she never fails, before storing her, to squeeze her crop, either
on the way or at the entrance of the dwelling, so as to make her
disgorge the delicious syrup, which she drinks by licking the tongue
which her unfortunate victim, in her death-agony, sticks out of her
mouth at full length. This profanation of a dying creature, whose enemy
squeezes its belly to empty it and feast on the contents, has something
so hideous about it that I should denounce the Philanthus as a brutal
murderess, if animals were capable of wrongdoing. At the moment of some
such horrible banquet, I have seen the Wasp, with her prey, seized by
the Mantis: the bandit was rifled by another bandit. And here is an
awful detail: while the Mantis held her transfixed under the points of
the double saw and was already munching her belly, the Wasp continued
to lick the honey of her Bee, unable to relinquish the delicious food
even amid the terrors of death. Let us hasten to cast a veil over these
horrors.

We will return to the Sphex, with whose burrow we must make ourselves
acquainted before we go further. This burrow is a hole made in fine
sand, or rather in a sort of dust at the bottom of a natural shelter.
Its entrance-passage is very short, merely an inch or two, without a
bend, and leads to a single, roomy, oval chamber. The whole thing is a
rough den, hastily dug out, rather than a leisurely and artistically
excavated dwelling. I have explained that the reason for this
simplicity is that the game is captured first and set down for a moment
on the hunting-field while the Wasp hurriedly makes a burrow in the
vicinity, a method of procedure which allows of but one chamber or cell
to each retreat. For who can tell whither the chances of the day will
lead the huntress for her second capture? The prisoner is heavy and the
burrow must therefore be near; so to-day’s home, which is too far away
for the next Ephippiger to be conveyed to it, cannot be utilized
to-morrow. Thus, as each prey is caught, there is a fresh excavation, a
fresh burrow, with its single chamber, now here, now there. Having said
this, we will try a few experiments to see how the insect behaves when
we create circumstances new to it.



EXPERIMENT I

A Sphex, dragging her prey along, is a few inches from the burrow.
Without disturbing her, I cut with a pair of scissors the Ephippiger’s
antennæ, which the Wasp, as we know, uses for harness-ropes. On
recovering from the surprise caused by the sudden lightening of her
load, the Sphex goes back to her victim and, without hesitation, now
seizes the root of the antenna, the short stump left by the scissors.
It is very short indeed, hardly a millimetre; [31] no matter: it is
enough for the Sphex, who grips this fag-end of a rope and resumes her
hauling. With the greatest precaution, so as not to injure the Wasp, I
now cut the two antennary stumps level with the skull. Finding nothing
left to catch hold of at the familiar points, the insect seizes, close
by, one of the victim’s long palpi and continues its hauling-work,
without appearing at all perturbed by this change in the harness. I
leave it alone. The prey is brought home and placed so that its head
faces the entrance to the burrow; and the Wasp goes in by herself, to
make a brief inspection of the inside of the cell before proceeding to
warehouse the provisions. Her behaviour reminds us of that of the
Yellow-winged Sphex in similar circumstances. I take advantage of this
short moment to seize the abandoned prey, remove all its palpi and
place it a little farther off, about half a yard from the burrow. The
Sphex reappears and goes straight to her captive, whom she has seen
from her threshold. She looks at the top of the head, she looks
underneath, on either side, and finds nothing to take hold of. A
desperate attempt is made: the Wasp, opening wide her mandibles, tries
to grab the Ephippiger by the head; but the pincers have not a
sufficient compass to take in so large a bulk and they slip off the
round, polished skull. She makes several fresh endeavours, each time
without result. She is at length convinced of the uselessness of her
efforts. She draws back a little to one side and appears to be
renouncing further attempts. One would say that she was discouraged; at
least, she smooths her wings with her hind-legs, while with her front
tarsi, which she first puts into her mouth, she washes her eyes. This,
so it has always seemed to me, is a sign in Hymenoptera of giving up a
job.

Nevertheless there is no lack of parts by which the Ephippiger might be
seized and dragged along as easily as by the antennæ and the palpi.
There are the six legs, there is the ovipositor: all organs slender
enough to be gripped boldly and to serve as hauling-ropes. I agree that
the easiest way to effect the storing is to introduce the prey head
first, drawn down by the antennæ; but it would enter almost as readily
if drawn by a leg, especially one of the front legs, for the orifice is
wide and the passage short or sometimes even non-existent. Then how is
it that the Sphex did not once try to seize one of the six tarsi or the
tip of the ovipositor, whereas she attempted the impossible, the
absurd, in striving to grip, with her much too short mandibles, the
huge skull of her prey? Can it be that the idea did not occur to her?
Then we will try to suggest it.

I offer her, right under her mandibles, first a leg, next the end of
the abdominal rapier. The insect obstinately refuses to bite; my
repeated blandishments lead to nothing. A singular huntress, to be
embarrassed by her game, not knowing how to seize it by a leg when she
is not able to take it by the horns! Perhaps my prolonged presence and
the unusual events that have just occurred have disturbed her
faculties. Then let us leave the Sphex to herself, between her
Ephippiger and her burrow; let us give her time to collect herself and,
in the calm of solitude, to think out some way of managing her
business. I leave her therefore and continue my walk; and, two hours
later, I return to the same place. The Sphex is gone, the burrow is
still open, and the Ephippiger is lying just where I placed her.
Conclusion: the Wasp has tried nothing; she went away, abandoning
everything, her home and her game, when, to utilize them both, all that
she had to do was to take her prey by one leg. And so this rival of
Flourens, who but now was startling us with her cleverness as she
dexterously squeezed her victim’s brain to produce lethargy, becomes
incredibly helpless in the simplest case outside her usual habits. She,
who so well knows how to attack a victim’s thoracic ganglia with her
sting and its cervical ganglia with her mandibles; she, who makes such
a judicious difference between a poisoned prick annihilating the vital
influence of the nerves for ever and a pressure causing only momentary
torpor, cannot grip her prey by this part when it is made impossible
for her to grip it by any other. To understand that she can take a leg
instead of an antenna is utterly beyond her powers. She must have the
antenna, or some other string attached to the head, such as one of the
palpi. If these cords did not exist, her race would perish, for lack of
the capacity to solve this trivial problem.



EXPERIMENT II

The Wasp is engaged in closing her burrow, where the prey has been
stored and the egg laid upon it. With her front tarsi she brushes her
doorstep, working backwards and sweeping into the entrance a stream of
dust which passes under her belly and spurts behind in a parabolic
spray as continuous as a liquid spray, so nimble is the sweeper in her
actions. From time to time the Sphex picks out with her mandibles a few
grains of sand, so many solid blocks which she inserts one by one into
the mass of dust, causing it all to cake together by beating and
compressing it with her forehead and mandibles. Walled up by this
masonry, the entrance-door soon disappears from sight.

I intervene in the middle of the work. Pushing the Sphex aside, I
carefully clear the short gallery with the blade of a knife, take away
the materials that close it and restore full communication between the
cell and the outside. Then, with my forceps, without damaging the
edifice, I take the Ephippiger from the cell, where she lies with her
head at the back and her ovipositor towards the entrance. The Wasp’s
egg is on the victim’s breast, at the usual place, the root of one of
the hinder thighs: a proof that the Sphex was giving the finishing
touch to the burrow, with the intention of never returning.

Having done this and put the stolen prey safely away in a box, I yield
my place to the Sphex, who has been on the watch beside me while I was
rifling her home. Finding the door open, she goes in and stays for a
few moments. Then she comes out and resumes her work where I
interrupted it, that is to say, she starts conscientiously stopping the
entrance to the cell by sweeping dust backwards and carrying grains of
sand, which she continues to heap up with scrupulous care, as though
she were doing useful work. When the door is once again thoroughly
walled up, the insect brushes itself, seems to give a glance of
satisfaction at the task accomplished, and finally flies away.

The Sphex must have known that the burrow contained nothing, because
she went inside and even stayed there for some time; and yet, after
this inspection of the pillaged abode, she once more proceeds to close
up the cell with the same care as though nothing out of the way had
happened. Can she be proposing to use this burrow later, to return to
it with a fresh victim and lay a new egg there? If so, her work of
closing would be intended to prevent the access of intruders to the
dwelling during her absence; it would be a measure of prudence against
the attempts of other diggers who might covet the ready-made chamber;
it might also be a wise precaution against internal dilapidations. And,
as a matter of fact, some Hunting Wasps do take care to protect the
entrance to the burrow by closing it temporarily, when the work has to
be suspended for a time. Thus I have seen certain Ammophilæ, whose
burrow is a perpendicular shaft, block the entrance to the home with a
small flat stone when the insect goes off hunting or ceases its mining
operations at sunset, the hour for striking work. But this is a slight
affair, a mere slab laid over the mouth of the shaft. When the insect
comes, it only takes a moment to remove the little flat stone; and the
entrance is free.

On the other hand, the obstruction which we have just seen built by the
Sphex is a solid barrier, a stout piece of masonry, where dust and
gravel form alternate layers all the way down the passage. It is a
definite performance and not a provisional defence, as is proved by the
care with which it is constructed. Besides, as I think I have shown
pretty clearly, it is very doubtful, considering the way in which she
acts, whether the Sphex will ever return to make use of the home which
she has prepared. The next Ephippiger will be caught elsewhere; and the
warehouse destined to receive her will be dug elsewhere too. But these,
after all, are only arguments: let us rather have recourse to
experiment, which is more conclusive here than logic.

I allowed nearly a week to elapse, in order to give the Sphex time to
return to the burrow which she had so methodically closed and to make
use of it for her next laying if such were her intention. Events
corresponded with the logical inferences: the burrow was in the
condition wherein I left it, still firmly closed, but without
provisions, egg or larva. The proof was decisive: the Wasp had not been
back.

So the plundered Sphex enters her house, makes a leisurely inspection
of the empty chamber, and, a moment afterwards, behaves as though she
had not perceived the disappearance of the bulky prey which but now
filled the cell. Did she, in fact, fail to notice the absence of the
provisions and the egg? Is she, who is so clear-sighted in her
murderous proceedings, dense enough not to realize that the cell is
empty? I dare not accuse her of such stupidity. She is aware of it. But
then why that other piece of stupidity which makes her close—and very
conscientiously close—an empty burrow, one which she does not purpose
to victual later? Here the work of closing is useless, is supremely
absurd; no matter: the insect performs it with the same ardour as
though the larva’s future depended on it. The insect’s various
instinctive actions are then fatally linked together. Because one thing
has been done, a second thing must inevitably be done to complete the
first or to prepare the way for its completion; and the two acts depend
so closely upon each other that the performing of the first entails
that of the second, even when, owing to casual circumstances, the
second has become not only inopportune but sometimes actually opposed
to the insect’s interests. What object can the Sphex have in blocking
up a burrow which has become useless, now that it no longer contains
the victim and the egg, and which will always remain useless, since the
insect will not return to it? The only way to explain this inconsequent
action is to look upon it as the inevitable complement of the actions
that went before. In the normal order of things, the Sphex hunts down
her prey, lays an egg and closes her burrow. The hunting has been done;
the game, it is true, has been withdrawn by me from the cell; never
mind: the hunting has been done, the egg has been laid; and now comes
the business of closing up the home. This is what the insect does,
without another thought, without in the least suspecting the futility
of her present labours.



EXPERIMENT III

To know everything and to know nothing, according as it acts under
normal or exceptional conditions: that is the strange antithesis
presented by the insect race. Other examples, also drawn from the Sphex
tribe, will confirm this conclusion. The White-edged Sphex (S.
albisecta) attacks medium-sized Locusts, whereof the different species
to be found in the neighbourhood of the burrow all furnish her with
their tribute of victims. Because of the abundance of these Acridians,
there is no need to go hunting far afield. When the burrow, which takes
the form of a perpendicular shaft, is ready, the Sphex merely explores
the purlieus of her lair, within a small radius, and is not long in
finding some Locust browsing in the sunshine. To pounce upon her and
sting her, despite her kicking, is to the Sphex the matter of a moment.
After some fluttering of its wings, which unfurl their carmine or azure
fan, after some drowsy stretching of its legs, the victim ceases to
move. It has now to be brought home, on foot. For this laborious
operation the Sphex employs the same method as her kinswomen, that is
to say, she drags her prize along between her legs, holding one of its
antennæ in her mandibles. If she encounters some grassy jungle, she
goes hopping and flitting from blade to blade, without ever letting
slip her prey. When at last she comes within a few feet of her
dwelling, she performs a manœuvre which is also practised by the
Languedocian Sphex; but she does not attach as much importance to it,
for she frequently neglects it. Leaving her captive on the road, the
Wasp hurries home, though no apparent danger threatens her abode, and
puts her head through the entrance several times, even going part of
the way down the burrow. She next returns to the Locust and, after
bringing her nearer the goal, leaves her a second time to revisit the
burrow. This performance is repeated over and over again, always with
the same anxious haste.

These visits are sometimes followed by grievous accidents. The victim,
rashly abandoned on hilly ground, rolls to the bottom of the slope; and
the Sphex on her return, no longer finding it where she left it, is
obliged to seek for it, sometimes fruitlessly. If she find it, she must
renew a toilsome climb, which does not prevent her from once more
abandoning her booty on the same unlucky declivity. Of these repeated
visits to the mouth of the shaft, the first can be very logically
explained. The Wasp, before arriving with her heavy burden, inquires
whether the entrance to the home be really clear, whether nothing will
hinder her from bringing in her game. But, once this first
reconnaissance is made, what can be the use of the rest, following one
after the other, at close intervals? Is the Sphex so volatile in her
ideas that she forgets the visit which she has just paid and runs
afresh to the burrow a moment later, only to forget this new inspection
also and to start doing the same thing over and over again? That would
be a memory with very fleeting recollections, whence the impression
vanished almost as soon as it was produced. Let us not linger too long
on this obscure point.

At last the game is brought to the brink of the shaft, with its antennæ
hanging down the hole. We now again see, faithfully imitated, the
method employed in the like case by the Yellow-winged Sphex and also,
but under less striking conditions, by the Languedocian Sphex. The Wasp
enters alone, inspects the interior, reappears at the entrance, lays
hold of the antennæ and drags the Locust down. While the
Locust-huntress was making her examination of the home, I have pushed
her prize a little farther back; and I obtained results similar in all
respects to those which the Cricket-huntress gave me. Each Sphex
displays the same obstinacy in diving down her burrow before dragging
in the prey. Let us recall here that the Yellow-winged Sphex does not
always allow herself to be caught by this trick of pulling away her
Cricket. There are picked tribes, strong-minded families which, after a
few disappointments, see through the experimenter’s wiles and know how
to baffle them. But these revolutionaries, fit subjects for progress,
are the minority; the remainder, mulish conservatives clinging to the
old manners and customs, are the majority, the crowd. I am unable to
say whether the Locust-huntress also varies in ingenuity according to
the district which she hails from.

But here is something more remarkable; and it is this with which I
wanted to conclude the present experiment. After repeatedly withdrawing
the White-edged Sphex’ prize from the mouth of the pit and compelling
her to come and fetch it again, I take advantage of her descent to the
bottom of the shaft to seize the prey and put it in a place of safety
where she cannot find it. The Sphex comes up, looks about for a long
time and, when she is convinced that the prey is really lost, goes down
into her home again. A few moments after, she reappears. Is it with the
intention of resuming the chase? Not the least in the world: the Sphex
begins to stop up the burrow. And what we see is not a temporary
closing, effected with a small flat stone, a slab covering the mouth of
the well; it is a final closing, carefully done with dust and gravel
swept into the passage until it is filled up. The White-edged Sphex
makes only one cell at the bottom of her shaft and puts one head of
game into this cell. That single Locust has been caught and dragged to
the edge of the hole. If she was not stored away, it was not the
huntress’s fault, but mine. The Wasp performed her task according to
the inflexible rule; and, also according to the inflexible rule, she
completes her work by stopping up the dwelling, empty though it be. We
have here an exact repetition of the useless exertions made by the
Languedocian Sphex whose home has just been plundered.



EXPERIMENT IV

It is almost impossible to make certain whether the Yellow-winged
Sphex, who constructs several cells at the end of the same passage and
stacks several Crickets in each, is equally illogical when accidentally
disturbed in her proceedings. A cell can be closed though empty or
imperfectly victualled, and the Wasp will none the less continue to
come to the same burrow in order to work at the others. Nevertheless, I
have reason to believe that this Sphex is subject to the same
aberrations as her two kinswomen. My conviction is based on the
following facts: the number of Crickets found in the cells, when all
the work is done, is usually four to each cell, although it is not
uncommon to find only three, or even two. Four appears to me to be the
normal number, first, because it is the most frequent and, secondly,
because, when rearing young larvæ dug up while they were still engaged
on their first joint, I found that all of them, those actually provided
with only two or three pieces of game as well as those which had four,
easily managed the various Crickets wherewith I served them one by one,
up to and including the fourth, but that after this they refused all
nourishment, or barely touched the fifth ration. If four Crickets are
necessary to the larva to acquire the full development called for by
its organization, why are sometimes only three, sometimes only two
provided for it? Why this enormous difference in the quantity of the
victuals, some larvæ having twice as much as the others? It cannot be
because of any difference in the size of the dishes provided to satisfy
the grub’s appetite, for all have very much the same dimensions; and it
can therefore be due only to the wastage of game on the way. We find,
in fact, at the foot of the banks whose upper stages are occupied by
the Sphex-wasps, Crickets that have been paralysed but lost, owing to
the slope of the ground, down which they have slipped when the
huntresses have momentarily left them, for some reason or other. These
Crickets fall a prey to the Ants and Flies; and the Sphex-wasps who
come across them take good care not to pick them up, for, if they did,
they would themselves be admitting enemies into the house.

These facts seem to me to prove that, while the Yellow-winged Sphex’
arithmetical powers enable her to calculate exactly how many victims to
capture, she cannot achieve a census of those which have safely reached
their destination. It is as though the insect had no mathematical guide
beyond an irresistible impulse that prompts her to hunt for game a
definite number of times. When the Sphex has made the requisite number
of journeys, when she has done her utmost to store the captures that
result from these, her work is ended; and she closes the cell whether
completely or incompletely provisioned. Nature has endowed her with
only those faculties called for in ordinary circumstances by the
interests of her larvæ; and, as these blind faculties, which cannot be
modified by experience, are sufficient for the preservation of the
race, the insect is unable to go beyond them.

I conclude therefore as I began: instinct knows everything, in the
undeviating paths marked out for it; it knows nothing, outside those
paths. The sublime inspirations of science and the astounding
inconsistencies of stupidity are both its portion, according as the
insect acts under normal or accidental conditions.



CHAPTER XI

AN ASCENT OF MONT VENTOUX


Thanks to its isolated position, which leaves it freely exposed on
every side to atmospheric influence; thanks also to its height, which
makes it the topmost point of France within the frontiers of either the
Alps or Pyrenees, our bare Provençal mountain, Mont Ventoux, lends
itself remarkably well to the study of the climatic distribution of
plants. At its base the tender olive thrives, with all that multitude
of semiligneous plants, such as the thyme, whose aromatic fragrance
calls for the sun of the Mediterranean regions; on the summit, mantled
with snow for at least half the year, the ground is covered with a
northern flora, borrowed to some extent from arctic shores. Half a
day’s journey in an upward direction brings before our eyes a
succession of the chief vegetable types which we should find in the
course of a long voyage from south to north along the same meridian. At
the start, your feet tread the scented tufts of the thyme that forms a
continuous carpet on the lower slopes; in a few hours they will be
treading the dark hassocks of the opposite-leaved saxifrage, the first
plant to greet the botanist who lands on the coast of Spitzbergen in
July. Below, in the hedges, you have picked the scarlet flowers of the
pomegranate, a lover of African skies; above you will pick a shaggy
little poppy, which shelters its stalks under a coverlet of tiny
fragments of stone and unfolds its spreading yellow corolla as readily
in the icy solitudes of Greenland and the North Cape as on the upper
slopes of the Ventoux.

These contrasts have always something fresh and stimulating about them;
and, after twenty-five ascents, they still retain their interest for
me. I made my twenty-third in August 1865. There were eight of us:
three whose chief object was to botanize and five attracted by a
mountain expedition and the panorama of the heights. Not one of our
five companions who were not interested in the study of plants has
since expressed a desire to accompany me a second time. The fact is
that the climb is a hard and tiring one; and the sight of a sunrise
does not make up for the fatigue endured.

One might best compare the Ventoux with a heap of stones broken up for
road-mending purposes. Raise this heap suddenly to a height of a mile
and a quarter, increase its base in proportion, cover the white of the
limestone with the black patch of the forests, and you have a clear
idea of the general aspect of the mountain. This accumulation of
rubbish—sometimes small chips, sometimes huge blocks—rises from the
plain without preliminary slopes or successive terraces that would
render the ascent less arduous by dividing it into stages. The climb
begins at once by rocky paths, the best of which is worse than the
surface of a road newly strewn with stones, and continues, becoming
ever rougher and rougher, right to the summit, the height of which is
6270 feet. Greenswards, babbling brooks, the spacious shade of
venerable trees, all the things, in short, that lend such charm to
other mountains, are here unknown and are replaced by an interminable
bed of limestone broken into scales, which slip under our feet with a
sharp, almost metallic ‘click.’ By way of cascades the Ventoux has
rills of stones; the rattle of falling rocks takes the place of the
whispering waters.

We are at Bédoin, at the foot of the mountain. The arrangements with
the guide have been made, the hour of the start fixed; the provisions
are being talked over and got ready. Let us try to rest, for we shall
have to spend a sleepless night on the mountain to-morrow. But sleeping
is just the difficulty; I have never managed it and that is where the
chief cause of fatigue lies. I would therefore advise those of my
readers who think of making a botanizing ascent of the Ventoux not to
arrive at Bédoin on a Sunday evening. They will thus avoid the noisy
bustle of an inn with a café attached to it, those endless loud-voiced
conversations, those echoing cannons of the billiard-balls, the ringing
of glasses, the drinking-songs, the ditties of nocturnal wayfarers, the
bellowing of the brass band at the ball hard by, and the other
tribulations inseparable from this blessed day of idleness and
jollification. Will they obtain a better rest on a week-day? I hope so,
but I do not guarantee it. For my part, I did not close an eye. All
night long, the rusty spit, working to provide us with food, creaked
and groaned under my bedroom. A thin board was all that separated me
from that machine of the devil.

But already the sky is growing light. A donkey brays beneath the
windows. It is time to get up. We might as well not have gone to bed.
Foodstuffs and baggage are strapped on; and, with a ‘Ja! Hi!’ from the
guide, we are off. It is four o’clock in the morning. At the head of
the caravan walks Triboulet, with his Mule and his Ass: Triboulet, the
Nestor of the Ventoux guides. My botanical colleagues inspect the
vegetation on either side of the road by the cold light of the dawn;
the others talk. I follow the party with a barometer slung from my
shoulder and a note-book and pencil in my hand.

My barometer, intended for taking the altitude of the principal
botanical halts, soon becomes a pretext for attacks on the gourd with
the rum. No sooner is a noteworthy plant observed than somebody cries:

‘Quick, let’s look at the barometer!’

And we all crowd around the gourd, the scientific instrument coming
later. The coolness of the morning and our walk make us appreciate
these references to the barometer so thoroughly that the level of the
stimulant falls even more swiftly than that of the mercury. In the
interests of the immediate future, I must consult Torricelli’s tube a
little less often.

As the temperature grows too cold for them, first the oak and the ilex
disappear by degrees; then the vine and the almond-tree; and next the
mulberry, the walnut-tree and the white oak. Box becomes plentiful. We
enter upon a monotonous region extending from the end of the cultivated
fields to the lower boundary of the beech-woods, where the predominant
plant is Satureia montana, the winter savory, known here by its popular
name of pébré d’asé, Ass’s pepper, because of the acrid flavour of its
tiny leaves, impregnated with essential oil. Certain small cheeses
forming part of our stores are powdered with this strong spice. Already
more than one of us is biting into them in imagination and casting
hungry glances at the provision-bags carried by the Mule. Our hard
morning exercise has brought appetite and more than appetite, a
devouring hunger, what Horace calls latrans stomachus. I teach my
colleagues how to stay this rumbling stomach until they reach the next
halt; I show them a little sorrel-plant, with arrow-head leaves, the
Rumex scutatus, or French sorrel; and, practising what I preach, I pick
a mouthful. At first they laugh at my suggestion. I let them laugh and
soon see them all occupied, each more eagerly than his fellow, in
plucking the precious sorrel.

While chewing the bitter leaves, we come to the beeches. These are
first big, solitary bushes, trailing on the ground; soon after, dwarf
trees, clustering close together; and, finally, mighty trunks, forming
a dense and gloomy forest, whose soil is a mass of rough limestone
blocks. Bowed down in winter by the weight of the snow, battered all
the year round by the fierce gusts of the mistral, many of the trees
have lost their branches and are twisted into grotesque positions, or
even lie flat on the ground. An hour or more is spent in crossing this
wooded zone, which from a distance shows against the sides of the
Ventoux like a black belt. Then once more the beeches become bushy and
scattered. We have reached their upper boundary and, to the great
relief of all of us, despite the sorrel-leaves, we have also reached
the stopping-place selected for our lunch.

We are at the source of the Grave, a slender stream of water caught, as
it bubbles from the ground, in a series of long beech-trunk troughs,
where the mountain shepherds come to water their flocks. The
temperature of the spring is 45° F.; and its coolness is a priceless
boon for us who have come from the sultry oven of the plain. The cloth
is spread on a charming carpet of Alpine plants, with glittering among
them the thyme-leaved paronychia, whose wide, thin bracts look like
silver scales. The food is taken out of the bags, the bottles extracted
from their bed of hay. On this side are the joints, the legs of mutton
stuffed with garlic, the stacks of loaves; on that, the tasteless
chickens, for our grinders to toy with presently, when the edge has
been taken off our appetite. At no great distance, set in a place of
honour, are the Ventoux cheeses spiced with winter savory, the little
pébré d’asé cheeses, flanked by Aries sausages, whose pink flesh is
mottled with cubes of bacon and whole pepper-corns. Over here, in this
corner, are green olives still dripping with brine and black olives
soaking in oil; in that other, Cavaillon melons, some white, some
orange, to suit every taste; and, down there, a jar of anchovies which
make you drink hard and so keep your strength up. Lastly, the bottles
are cooling in the ice-cold water of the trough over there. Have we
forgotten anything? Yes, we have not mentioned the crowning side-dish,
the onions, to be eaten raw with salt. Our two Parisians—for we have
two among us, my fellow-botanists—are at first a little startled by
this very invigorating bill of fare; soon they will be the first to
burst into praises. Are we all ready? Then let us sit down.

And now begins one of those Homeric repasts which mark red-letter days
in one’s life. The first mouthfuls are almost frenzied. Slices of
mutton and chunks of bread follow one another with alarming rapidity.
Each of us, without communicating his apprehensions to the others,
casts an anxious glance at the victuals and asks himself:

‘If this is the way we are going on, shall we have enough for to-night
and to-morrow?’

However, the craving is allayed; we began by devouring in silence, we
now eat and talk. Our apprehensions for the morrow are likewise
relieved; and we give due credit to the man who ordered the menu, who
foresaw this hunger-fit and who arranged to cope with it worthily. The
time has come for us to appreciate the victuals as connoisseurs. One
praises the olives, stabbing them one by one with the point of his
knife; another lauds the anchovies as he cuts up the little
ochre-coloured fishes on his bread; a third waxes enthusiastic about
the sausage; and all with one accord extol the pébré d’asé cheeses, no
larger than the palm of a man’s hand. Pipes and cigars are lit; and we
stretch ourselves on our backs in the grass, with the sun shining down
upon us.

An hour’s rest and we are off again, for time presses. The guide with
the baggage will go alone, towards the west, skirting the edge of the
woods, which has a Mule-path. He will wait for us at the Jas, or
Bâtiment, on the upper boundary of the beeches, some 5000 feet above
the level of the sea. The Jas is a large stone hut, which is to shelter
us, man and beast, to-night. As for us, we continue the ascent to the
ridge, by following which we shall reach the highest peak more easily.
From the top, after sunset, we shall go down to the Jas, where the
guide will have arrived long before us. This is the plan proposed and
adopted.

We reach the crested ridge. On the south, the comparatively easy slopes
which we have just climbed stretch as far as the eye can see; on the
north, the scene is full of wild grandeur: the mountain, sometimes hewn
perpendicularly, sometimes carved into rough steps, alarmingly steep,
is little else than a sheer precipice a mile high. If you throw a
stone, it never stops, but falls from rock to rock until it reaches the
bottom of the valley, where you can distinguish the bed of the
Toulourenc looking like a ribbon. While my companions loosen masses of
rock and send them rolling into the abyss so that they may watch the
frightful fall, I discover under a broad flat stone one of my old
insect acquaintances, the Hairy Ammophila, whom I had always met by
herself on the roadside banks in the plain, whereas here, almost at the
top of the Ventoux, I find her to the number of several hundreds heaped
up under one and the same shelter.

I was beginning to investigate the reasons for this agglomeration, when
the southerly breeze, which already during the morning had inspired us
with a few vague fears, suddenly brought up a cohort of clouds which
melted into rain. Before we knew it, we were shrouded in a thick,
drizzling mist, which prevented us from seeing two yards in front of
us. By an unfortunate coincidence, one of us, my good friend Delacour,
had strayed aside in search of Euphorbia saxitalis, one of the
botanical curiosities of these heights. Making a speaking-trumpet of
our hands, we shouted as one man. No answer came. Our voices were lost
in the flaky thickness and the dull sound of the whirling mist. As the
wanderer could not hear us, we had to look for him. In the darkness it
was impossible to see one another at a distance of two or three yards;
and I was the only one of the seven to know the locality. So that
nobody might be left in the lurch, we took hands and I placed myself at
the head of the chain. For some minutes we played a regular game of
blind-man’s-buff, leading to nothing. No doubt, on seeing the clouds
drift up, Delacour, who knew the Ventoux, had taken advantage of the
last gleams of light to hasten to the shelter of the Jas. We resolved
to make for it ourselves as quickly as possible, for already our
clothes were streaming with rain inside as well as out. Our white-duck
trousers were sticking to us like a second skin.

A serious difficulty arose: the hurrying backwards and forwards, the
twisting and turning, while we looked about us, had reduced me to the
plight of a person whose eyes are bandaged and who is then made to spin
round on his heels. I had lost all sense of direction; I had not the
least idea which was the southern slope. I questioned this man and
that; opinions were divided and most uncertain. The upshot was that not
one of us could say where the north lay and where the south. Never in
all my life had I realized the value of the points of the compass as I
did at that moment. All around us was the mystery of the grey haze;
beneath our feet we could just make out the beginning of a slope here
and a slope there. But which was the right one? We had to make a choice
and to launch out boldly. If, by bad luck, we went down the northern
slope, we risked breaking our bones over the precipices the sight of
which had but now filled us with dread. Perhaps not one of us would
survive it. I passed a few minutes of acute perplexity.

‘Let’s stay here,’ said the majority, ‘and wait till the rain stops.’

‘That’s bad advice,’ replied the others, of whom I was one, ‘that’s bad
advice: the rain may last a long while; and, wet through as we are, we
shall freeze on the spot at the first chill of night.’

My worthy friend Bernard Verlot, who had come from the Paris Jardin des
Plantes on purpose to climb the Ventoux in my company, displayed an
imperturbable calmness, trusting to my good sense to get us out of our
scrape. I drew him a little to one side, in order not to increase the
panic of the others, and revealed my terrible fears to him. We held a
council of two and tried to make up by the compass of reasoning for the
absence of the magnetic needle.

‘When the clouds came,’ I asked him, ‘wasn’t it from the south?’

‘From the south, certainly.’

‘And, though one could hardly perceive the wind, the rain slanted
slightly from south to north?’

‘Yes, I noticed that as long as I could see anything. Isn’t that enough
to tell us the way? Let us go down on the side from which the rain
comes.’

‘I thought of that, but I have my doubts. The wind is not strong enough
to have a definite direction. It may be an eddying breeze, as happens
on a mountain-top surrounded by clouds. There is nothing to tell me
that the direction is still the same and that the wind is not now
blowing from the north.’

‘I have my doubts also. Then what shall we do?’

‘What shall we do? That’s the difficulty! But look here: if the wind
has not changed, we ought to be wetter on the left, because we got the
rain on that side until we lost our bearings. If it has changed, we
must be more or less equally wet all over. Let us feel ourselves and
decide. Will that do?’

‘Yes.’

‘And suppose I’m wrong?’

‘You’re not wrong.’

The matter was explained to our companions in a few words. All felt
themselves, not outside, which would not have been enough, but right
inside their underclothing, and it was with unspeakable relief that I
heard them unanimously declare their left side to be much wetter than
the right. The wind had not changed. All was well; and we determined to
go towards the rain. The chain was formed once more, with myself at the
head and Verlot in the rear, so as to leave no stragglers behind.
Before starting, I asked my friend, for the last time:

‘Well, shall we risk it?’

‘Yes, let’s risk it; I’ll follow you.’

And we plunged blindly into the formidable unknown.

We had not taken twenty strides, twenty of those strides which one is
not able to control on a steep slope, before all fear of danger was
over. Under our feet was not the empty space of the abyss but the
longed-for ground, the ground covered with small stones, which rolled
down in long torrents. To all of us, this rattling sound, denoting a
firm footing, was heavenly music. In a few minutes we reached the upper
edge of the beeches. Here the darkness was even greater than at the top
of the mountain: we had to stoop to the ground to see where we were
walking. How, in the gloom, were we to find the Jas, buried away in the
dense wood? Two plants, the assiduous haunters of places frequented by
man—the Chenopodium bonus-Henricus, or good-king-Henry, and the common
nettle—served me as a clue. I swept my free hand through the air as I
went along. Each sting that I felt told me of a nettle, in other words,
a landmark. Verlot, in the rear, also lunged about as best he could and
let smarting stings make up for the lack of vision. Our companions had
but little faith in this style of reconnoitring. They spoke of
continuing the furious descent, of going back, if necessary, all the
way to Bédoin. Verlot, more trustful of the botanical insight with
which he himself was so richly endowed, joined me in pursuing our
search, in reassuring the more demoralized and in showing them that it
was possible, by questioning the plants with our hands, to reach our
night’s lodging in spite of the darkness. They gave way to our
arguments; and, not long after, pressing on from one clump of nettles
to another, our party arrived at the Jas.

There we found Delacour, as well as the guide with our luggage,
sheltered betimes from the rain. A blazing fire and a change of clothes
soon restored our wonted cheerfulness. A block of snow, brought from
the valley near by, was hung in a bag in front of the hearth. A bottle
caught the water as the snow melted: this was the cistern for our
evening meal. And the night was spent on a bed of beech-leaves, rubbed
into powder by our predecessors; and they were numerous. Who knows how
many years had passed since that mattress, now a vegetable mould, was
last renewed!

Those who could not sleep were told off to keep up the fire. There was
no lack of hands to stir it, for the smoke, which had no other outlet
than a large hole made by the partial collapse of the roof, filled the
hut with an atmosphere fit to smoke herrings. To obtain a few mouthfuls
of breathable air, we had to seek them in the lower strata, with our
noses almost on the ground. And so we coughed and cursed and poked the
fire, but vainly tried to sleep. We were all afoot by two o’clock in
the morning, ready to climb the highest cone and watch the sunrise. The
rain had stopped, the sky was glorious, promising a perfect day.

During the ascent some of us felt a sort of seasickness, caused first
by fatigue and secondly by the rarefaction of the air. The barometer
had fallen 5·4 inches; the air which we were breathing had lost a fifth
of its density and was therefore one-fifth less rich in oxygen. Had we
been in good condition, this slight alteration in the air would have
passed unnoticed; but, coming immediately after the exertions of the
day before and a sleepless night, it increased our discomfort. And so
we climbed slowly, with aching legs and panting chests. More than one
of us had to stop and rest after every twentieth step.

At last we were there. We took refuge in the rustic chapel of
Sainte-Croix to take breath and counteract the nipping morning air by a
pull at the gourd, which this time was drained to the last drop. Soon
the sun rose. Ventoux projected to the extreme limits of the horizon
its triangular shadow, whose sides became brightly tinged with violet
by the effect of the diffracted rays. To the south and west stretched
misty plains, where, when the sun was higher in the heavens, we should
be able to make out the Rhône, looking like a silver thread. On the
north and east, under our feet, lay an enormous bank of clouds, a sort
of ocean of cotton-wool, whence peeped, like islands of slag, the dark
summits of the lower mountains. A few tops, with their trailing
glaciers, gleamed in the direction of the Alps.

But botany called our attention and we had to tear ourselves from this
magic spectacle. The time of our ascent, in August, was a little late
in the year; many plants were no longer in flower. Would you do some
really fruitful herborizing? Be there in the first fortnight of July;
above all, be ahead of the grazing herds: where the Sheep has browsed
you will gather none but wretched leavings. While still spared by the
hungry flocks, the top of the Ventoux in July is a literal bed of
flowers; its loose stony surface is studded with them. My memory
recalls, all streaming with the morning dew, those elegant tufts of
Androsace villosa, with its pink-centred white blooms; the Mont-Cenis
violet, spreading its great blue blossoms over the chips of limestone;
the spikenard valerian, which blends the sweet perfume of its flowers
with the offensive odour of its roots; the wedge-leaved globularia,
forming close carpets of bright green dotted with blue capitula; the
Alpine forget-me-not, whose blue rivals that of the skies; the Candolla
candytuft, whose tiny stalk bears a dense head of little white flowers
and goes winding among the loose stones; the opposite-leaved saxifrage
and the musky saxifrage, both of them packed into little dark cushions,
studded in the first case with purple flowers and in the second with
white flowers washed with yellow. When the sun’s rays are hotter, we
shall see fluttering idly from one tuft of blossom to another a
magnificent Butterfly with white wings adorned with four bright-crimson
spots, surrounded with black. ’Tis Parnassius Apollo, the beautiful
occupant of the Alpine solitudes, near the eternal snows. Her
caterpillar lives on the saxifrages.

Here let us end this sketch of the sweet joys that await the naturalist
on the summit of Mont Ventoux and return to the Hairy Ammophila, who
was lurking yesterday in her legions under the shelter of a stone when
the misty rain came and enshrouded us.



CHAPTER XII

THE TRAVELLERS


I have told in the last chapter how, on the ridges of Mont Ventoux, at
a height of nearly 6000 feet, I had one of those entomological
windfalls which would be rich in results if they occurred often enough
to serve the purpose of continuous study. Unfortunately, mine was a
solitary instance and I despair of ever repeating it. I can therefore
only base conjectures on it, in the hope that future observers will
replace my surmises with certainties.

Under the shelter of a broad, flat stone I discovered some hundreds of
Ammophilæ (A. hirsuta), heaped one on top of the other almost as
closely as the Bees in a swarm. As soon as I lifted the stone, all this
little hairy world began to run about, without making any attempt to
fly away. I shifted the mass by handfuls: not one of the Wasps looked
as though she wished to desert the rest. They seemed indissolubly
united by common interests; none of them would go unless all went. I
examined with every possible care the flat stone that sheltered them,
as well as the ground underneath and just around it, and discovered not
a thing to tell me the cause of this strange assemblage. Having nothing
better left to do, I tried to count them; and it was then that the
clouds came and put an end to my observations and plunged us into that
darkness of which I have described the anxious consequences. At the
first drops of rain, before leaving the spot, I hastened to put back
the stone and replace the Ammophilæ in their shelter. I give myself a
good mark, which I hope that the reader will confirm, for having taken
the precaution not to leave the poor insects whom my curiosity had
disturbed at the mercy of the downpour.

The Hairy Ammophila is not rare in the plains, but she is always found
singly by the side of the paths or on the sandy slopes, now engaged in
digging her well, anon busily carting her heavy caterpillar. She lives
alone, like the Languedocian Sphex; and it was a great surprise to me
to come upon such a number of this species collected under one and the
same stone almost at the top of Mont Ventoux. Instead of the isolated
specimen which I had known hitherto, a crowded company presented itself
to my eyes. Let us try to trace the probable causes of this
agglomeration.

The Hairy Ammophila is one of the very rare exceptions among the
Digger-wasps in the matter of nest-building; she gets hers ready in the
early days of spring. Towards the end of March, if the season be mild,
or at latest in the first fortnight of April, when the Crickets assume
the adult form and laboriously cast the skin of infancy on the
threshold of their homes, when the poet’s-narcissus puts forth its
first flowers and the Bunting utters his long-drawn call from the top
of the poplars in the fields, Ammophila hirsuta is at work digging a
home for her grubs and victualling it, whereas the other Ammophilæ and
the various Hunting Wasps in general postpone this labour until autumn,
during September and October. This early nidification, preceding by six
months the date adopted by the vast majority, at once suggests a few
reflections.

We wonder if the Ammophilæ whom we find occupied with their burrows in
the first days of April are really insects of that year, that is to
say, if these spring workers completed their metamorphosis and left
their cocoons during the previous three months. The general rule is for
the Digger to become a perfect insect, to quit her subterranean
dwelling and to busy herself with her larvæ all in one season. Most of
the Predatory Wasps leave the galleries where they lived as larvæ in
the months of June and July and display their talents as miners and
hunters in the following months of August, September and October.

Does a similar law apply to the Hairy Ammophila? Does the same season
witness the insect’s final transformation and its labours? It is very
doubtful, for the Wasp occupied on the work of the burrow at the end of
March would in that case have to complete her metamorphosis and to
break out of her cocoon during the winter, or at latest in February.
The severity of the climate at this period does not allow us to accept
such a conclusion. It is not at a time when the bleak mistral howls for
a fortnight without intermission and freezes the ground hard, it is not
at a time when snowstorms follow close upon that icy blast, that the
delicate transformations of the nymphosis are able to take place or the
insect to dream of abandoning the shelter of its cocoon. It needs the
warm moisture of the earth under the summer sun before it can leave its
cell.

If I knew the exact period at which the Hairy Ammophila emerges from
her native burrow, this would help me greatly; but, to my intense
regret, I do not know it. My notes, collected day by day, with the lack
of order inevitable in a type of research that is constantly subject to
the hazards of the unforeseen, are silent on this point, of which I
clearly perceive the importance now that I am trying to arrange my
materials in order to write these lines. I find the Sandy Ammophila
mentioned as hatching on the 5th of June and the Silvery Ammophila on
the 20th of that month; but my records contain not a word that relates
to the hatching of the Hairy Ammophila. It is a detail which, by an
oversight, has never been cleared up. The dates given for the other two
species come under the general law, which lays down that the perfect
insect shall appear during the hot season. I fix the same period, by
analogy, as that for the Hairy Ammophila’s emergence from the cocoon.

Then whence come the Ammophilæ whom we see working at their burrows at
the end of March and in April? We are driven to the conclusion that
these Wasps belong not to the present but to the previous year; that
they left their cells at the usual time, in June and July, got through
the winter and began to make their nests as soon as the spring came. In
a word, they are hibernating insects. And this conclusion is fully
borne out by experiment.

If we will but search patiently in the perpendicular banks of earth or
sand facing due south, especially those in which generations of
different honey-gathering Bees have succeeded one another year after
year and riddled the wall with a labyrinth of tunnels until it looks
like an enormous sponge, we are almost sure, in midwinter, to find the
Hairy Ammophila snugly ensconced in the shelters provided by the sunny
bank, alone or in groups of three or four, idly awaiting the arrival of
the fine weather. I have been able to give myself as often as I wished
this little treat of renewing my acquaintance, amid the gloom and cold
of winter, with the pretty Wasp who enlivens the greensward beside the
paths at the first notes of the Bunting and the Cricket. When there is
no wind and the sun is shining brightly, the warmth-loving insect comes
to its threshold to bask luxuriously in the hottest rays, or it will
even timidly venture outside and, step by step, stroll over the surface
of the spongy bank, polishing its wings as it goes. Even so does the
little Grey Lizard behave, when the sun once more begins to warm the
old wall that represents his native land.

But vain would be our search in winter, even in the most sheltered
refuges, for a Cerceris, Sphex, Philanthus, Bembex or other Wasp with
carnivorous grubs. All died after their autumnal labours and their race
is not represented, in the cold season, save by the larvæ slumbering in
their cells. It is, then, by a most rare exception that the Hairy
Ammophila, hatched in the hot season, spends the following winter in
some warm shelter; and this is the reason why she appears so very early
in the spring.

With these data to go upon, let us try to explain the cluster of
Ammophilæ which I observed on the ridges of Mont Ventoux. What could
these numerous Wasps have been doing, heaped up under their stone? Were
they preparing to take up their winter quarters there and, slumbering
under cover, to await the season favourable to their work? Everything
tends to show that this is improbable. It is not in August, at the
hottest time of year, that an animal is overcome with its winter
drowsiness. Nor is it any use to suggest the want of food, of honeyed
juices sucked from the flowers. The September showers are at hand; and
vegetation, suspended for a moment by the heat of the dog-days, will
gather fresh vigour and cover the fields with blossoms almost as
diverse as those of spring. This season of revelry for the majority of
Wasps and Bees could never be a period of torpor for the Hairy
Ammophila.

And then have we any right to imagine that the heights of Ventoux,
swept by the gusts of the mistral, which sometimes uproots both beech
and pine; that crests where the north wind sends the snow-flakes
whirling for six months in succession; that peaks wrapped for the best
part of the year in cold cloud-fogs, can be adopted as a winter refuge
by an insect enamoured of the sun? One might as well suggest that it
should hibernate among the ice-floes of the North Cape. No, it is not
here that the Hairy Ammophila can spend the cold season. The group
which I observed was only passing through. At the first hint of rain, a
hint that escaped us but could not escape the insect, which is so
highly sensitive to the atmospheric variations, the band of travellers
had taken shelter under a stone, waiting for the rain to stop before
resuming their flight. Whence did they come? Whither were they bent?

In this same month of August, and still more in September, we are
visited, in our warm, olive-clad regions, by caravans of little birds
of passage descending by easy stages from the countries where they have
wooed and loved, countries cooler, more thickly wooded, less wild than
ours, where they have reared their broods. They arrive almost on a
fixed day, in an unvarying order, as though guided by the dates of a
calendar known only to themselves. They sojourn for some time in our
plains, a halting-place rich in insects, which form the exclusive fare
of most of them; they ransack every clod in our fields, where the
ploughshare by now has laid bare in the furrows a multitude of grubs,
their special delight; thanks to this diet, they soon put on a fine
cushion of fat, a storehouse of reserve provisions for the coming
exertions; and at last, supplied with this viaticum, they continue
their southward flight, making for the winterless lands where insects
are never lacking: Spain, Southern Italy, the Mediterranean islands and
Africa. This is the season for brave sport with the gun and for dainty
roasts of small birds.

The first to arrive is the Shore-lark, or, as he is called in these
parts, the Crèou. August is hardly here before we see him exploring the
pebbly fields, in search of the little seeds of setaria, an ill weed
that overruns our tilled soil. At the least alarm he flies away with a
harsh clattering in his throat which is not badly represented by his
Provençal name. He is soon followed by the Whin-chat, who preys
placidly on small Weevils, Locusts, and Ants in the old lucern-fields.
With him begins the long line of small winged things, the glory of the
spit. It is continued, when September comes, by the most famous of
them, the Common Wheat-ear, or White-tail, extolled by all who are able
to appreciate his exalted qualities. No Beccafico of the Roman
epicures, immortalized in Martial’s epigrams, ever equalled the
exquisite, scented ball of fat that is the Wheat-ear, grown shamefully
stout on gluttonous living. He is an unbridled devourer of every kind
of insect. The notes which I have taken as a sportsman and naturalist
bear witness to the contents of his gizzard. It includes the whole
little world of the fallow fields: grubs and Weevils of every species,
Locusts, Tortoise-beetles, Golden Apple-beetles, Crickets, Earwigs,
Ants, Spiders, Wood-lice, Snails, Millipedes, and ever so many others.
And, as a change from this full-flavoured diet, there are grapes,
blackberries and dogberries. Such is the bill of fare for which the
Wheat-ear is ever in search, as he flies from clod to clod, with the
white feathers of his outspread tail giving him that fictitious look of
a Butterfly on the wing. And Heaven knows what prodigies of plumpness
he is able to achieve.

He has only one master in the art of self-fattening. This is one whose
migration synchronizes with his, one who is likewise an enthusiastic
insect-eater: the Bush-pipit, as the nomenclators so absurdly call him,
whereas the dullest of our shepherds never hesitates to speak of him as
the Grasset, the champion fat bird. The name in itself fully describes
his leading characteristic. No other achieves such a degree of obesity.
A moment comes when, laden with pads of fat up to its wings, its neck
and the back of its head, the bird looks like a little pat of butter.
The poor thing can hardly flutter from one mulberry-tree to the next,
where it stops to pant in the thick leafage, half choked with melting
fat, a martyr to its passion for Weevils.

October brings us the slender White Wagtail, half pearly grey, half
white, with a large black-velvet chest-protector. The graceful little
bird, trotting along and cocking up its tail, follows the ploughman
almost under the horses’ feet and picks the grubs in the new-turned
furrow. About the same time the Skylark arrives, first in little
companies sent out as scouting-parties, next in countless battalions,
which take possession of the cornfields and fallow land, with their
plentiful setaria-seeds, the bird’s usual fare. Then, in the plain,
amid the universal glitter of dewdrops and rime-crystals hanging from
every blade of grass, the treacherous mirror shoots forth its
intermittent flashes in the rays of the morning sun; then the little
Owl, released by the hunter’s hand, makes his short flight, alights,
starts up again convulsively, rolling frightened eyes; and the Lark
arrives, dipping on the wing, curious to obtain a closer view of the
bright apparatus or the grotesque bird. He is there, in front of you, a
dozen yards away, with feet pendant and wings outspread like the Dove
in a sacred picture. Now then: take aim and fire! I wish my readers the
excitement of this fascinating sport.

With the Skylark, often in the same companies, comes the Titlark,
commonly called the Sisi. Here again an onomatopœia gives us the bird’s
little call-note. None goes with greater fury for the Owl, round whom
he manœuvres and hovers constantly. But we will not continue the list
of the birds of passage that visit us. Most of them make but a short
halt here; they stay for a few weeks, attracted by the abundance of
food, especially of insects; then, plump and strong, they pursue their
southward journey. Others, fewer these, take up their winter quarters
in our plains, where snow is very rare and where thousands of little
seeds lie exposed on the ground, even in the depth of winter. One of
these is the Skylark, who gives his attention to the corn-fields and
fallows; another is the Titlark, who prefers the lucern-fields and
meadows.

The Skylark, so common in almost every part of France, does not nest in
the Vaucluse plains, where his place is taken by the Crested Lark, that
frequenter of the broad highway, the roadmender’s friend. But one need
not go far north to find the favourite spots for the Skylark’s broods:
the next department, the Drôme, is rich in his nests. It is very
probable therefore that, out of the numbers of Skylarks that come to
take possession of our plains for the whole of autumn and winter, there
are many that travel no farther than the Drôme. They have only to
migrate to the next department to find plains free from snow and a
steady supply of tiny seeds. A like migration to a short distance seems
to me to have caused the crowd of Ammophilæ which I surprised near the
top of Mont Ventoux. I have shown that this Wasp spends the winter in
the perfect insect state, hidden in some shelter and waiting until
April to make her nest. She also, like the Skylark, must take her
precautions against the frosty season. Though she need not fear the
lack of food, being capable of fasting until the return of the flowers,
she must at least, delicate creature that she is, guard against the
fatal attacks of the cold. She will therefore flee snowy country, the
districts where the ground freezes to a great depth; she will assemble
in a migratory caravan, after the manner of the birds, and, crossing
hill and dale, will select a home in old walls and sandy banks warmed
by the southern sun. Then, when the cold is past, all or part of the
troop will return to the place whence they came. This would explain the
Ventoux band of Ammophilæ. It was a travelling tribe which, coming from
the cold uplands of the Drôme and descending into the warm plains
beloved of the olive-tree, had crossed the wide, deep valley of the
Toulourenc and, when surprised by the rain, had called a halt on the
mountain-ridge. Apparently, therefore, the Hairy Ammophila has to
migrate in order to escape the cold of winter. At the time when the
little birds of passage start their procession of caravans, she too
journeys from a colder to a warmer neighbourhood. She has but to cross
a few valleys and a few mountains to find the climate which she wants.

I have two other instances of extraordinary gatherings of insects at
great heights. In October I have found the chapel at the summit of Mont
Ventoux covered with Coccinella septempunctata, the Seven-spot
Ladybird. The insects clinging to the stone of both the roof and walls
were packed so close together that the rude edifice looked, from a
little way off, like a piece of coral-work. I should not care to guess
the myriad numbers of the Ladybirds collected there. Those Aphis-eaters
had certainly not been attracted by the hope of food to the top of the
Ventoux, some 6000 feet above the level of the sea. Vegetation is too
scanty up there; and no Plant-louse ever ventured so high.

On another occasion, in June, on the tableland of Saint-Amans, a
neighbour of the Ventoux, at a height of 2400 feet, I witnessed a
similar gathering, only much less numerous. At the most prominent part
of the plateau, on the edge of a bluff of perpendicular rocks, stands a
cross with a pedestal of hewn stone. On each face of this pedestal and
on the rocks supporting it, the same Beetles, the Seven-spot Ladybirds
of the Ventoux, had gathered in their legions. The insects were mostly
stationary; but, wherever the sun beat at all fiercely, there was a
continual exchange between the newcomers, anxious to find room, and the
old occupants of the wayside cross, who took to their wings only to
return after a short flight.

Nothing here, any more than on the summit of the Ventoux, was able to
tell me the cause of these strange meetings on arid spots, containing
no Plant-lice and possessing no attraction for Ladybirds; nothing
suggested the secret of these crowded gatherings on masonry situated at
a great height. Were these again instances of entomological migration?
Were they general musterings, similar to that of the Swallows on the
day before their common departure? Were they meeting-places whence the
swarm of Ladybirds was to make for some district richer in edibles? It
is possible, but it is also very extraordinary. The Ladybird has rarely
been noted as a devotee of travel. She seems to us a very stay-at-home
creature when we see her butchering the Green-fly on our rose-trees and
the Black-fly on our beans; and yet, with her short wings, she holds
plenary assemblies, in immense numbers, on the summit of Mont Ventoux,
where the Martin himself ascends only at moments of violent energy. Why
these meetings at such altitudes? What can be the reason of this
predilection for blocks of masonry?



CHAPTER XIII

THE AMMOPHILÆ


A slender waist, a slim shape; an abdomen tapering very much at the
upper part and fastened to the body as though by a thread; black
raiment with a red sash across the belly: there you have a summary
description of these burrowers, who are akin to the Sphex in form and
colouring, but differ greatly from them in habits. The Sphex hunt
Orthoptera—Locusts, Grasshoppers, Crickets—while caterpillars are the
quarry of the Ammophilæ. This change of prey in itself suggests new
methods in the lethal tactics of instinct.

If the name did not sound so pleasant to the ear, I would willingly
quarrel with the term Ammophila, which means ‘sand-lover,’ as being too
exclusive and often erroneous. The real lovers of sand, of dry, dusty,
streaming sand, are the Bembex, who prey on Flies; but the
caterpillar-hunters, whose story I now propose to relate, have no
predilection for ordinary shifting sand, and even avoid it as being
liable to landslips on the slightest provocation. Their perpendicular
shaft, which has to remain open until the cell receives the provisions
and an egg, requires a firmer setting if it is not to be prematurely
blocked. What they want is a light soil, easily tunnelled, in which the
sandy element is cemented with a little clay and lime. Edges of paths,
sunny banks where the grass is rather bare: those are the favourite
spots. In spring, quite early in April, we see the Hairy Ammophila (A.
hirsuta) there; when September and October come, we find the Sandy
Ammophila (A. sabulosa), the Silvery Ammophila (A. argentata), and the
Silky Ammophila (A. holosericea). I will here condense the information
which I have gathered from the four species.

In the case of all four the burrow is a vertical shaft, a sort of well,
possessing at most the diameter of a thick goose-quill and a depth of
about two inches. At the bottom is the cell, which is always solitary
and consists of a mere widening of the entrance-shaft. It is, when all
is said, a poor lodging, obtained economically, in one day’s work; the
larva will find no protection there against the winter except from the
four wrappers of its cocoon, copied from that of the Sphex. The
Ammophila digs by herself, quietly, without hurrying, without any
joyous enthusiasm. As usual, the fore-tarsi serve as rakes and the
mandibles do duty as mining-tools. When some grain of sand offers too
much resistance to its removal, you hear rising from the bottom of the
well, as though to give voice to the insect’s efforts, a sort of shrill
grating sound produced by the quivering of the wings and of the whole
body. At frequent intervals the Wasp appears in the open with a load of
refuse in her teeth, some bit of gravel which she flies away with and
drops at a distance of a few inches, so as not to litter the place. Of
the grains extracted some appear to deserve special attention, owing to
their shape and size; at least, the Ammophila does not treat them as
she does the rest: instead of flying off and dropping them far from the
work-yard, she removes them on foot and lays them near the well. These
are picked materials, ready-made blocks of stone which will serve
presently for closing the dwelling.

This outside work is performed with measured movements and solemn
diligence. The insect stands high on its legs, with its abdomen
stretched at the end of its long pedicle, and turns round slowly,
pivoting its whole body stiffly, with the geometrical rigidity of a
line revolving on itself. If it wishes to fling to a distance the
rubbish which it thinks will be in the way, it does so in short silent
flights, often backwards, as though the Wasp, emerging from her well
head last, avoided turning, so as to save time. It is the species
carrying their abdomens on the longest stalks, such as the Sandy
Ammophila and the Silky Ammophila, which mainly display this
automaton-like rigidity in action. That belly swelling into a pear at
the end of a thread is in fact a very delicate thing to steer: a sudden
movement might warp the fine stalk. So we must walk with a sort of
geometrical rigour; if we have to fly, we will do so backwards, to
avoid tacking too often. On the other hand, the Hairy Ammophila, who
has a short abdominal pedicle, works at her burrow with the heedless,
nimble movements which we admire in most of the Digger-wasps. She has
more freedom of action, because her belly does not get in her way.

The home is dug. At a later hour in the day, or even merely when the
sun has left the place where the burrow has just been bored, the
Ammophila invariably visits the little heap of stones placed in reserve
during the excavating, with the object of choosing a bit to suit her.
If there is nothing that satisfies her needs, she explores the
neighbourhood and soon discovers what she wants, a small flat stone
slightly larger in diameter than the mouth of her hole. She carries off
this slab in her mandibles and lays it, as a temporary door, over the
opening of the burrow. To-morrow, when the weather is once more hot and
the sun bathes the slopes and encourages hunting, the Wasp will know
quite well how to find her home, rendered inviolable by the massive
door; she will come back with a paralysed caterpillar, grasped by the
skin of its neck and dragged between its captor’s legs; she will lift
the slab, which nothing distinguishes from other little stones around
and which she alone is able to identify; she will let down the game to
the bottom of the well, lay her egg, and close the house for good by
sweeping into the perpendicular shaft all the rubbish which she has
kept in the vicinity.

Time after time the Sandy Ammophila and the Silvery Ammophila have
shown me this temporary closing of the hole when the sun begins to go
down and when the lateness of the hour compels the victualling to be
put off till the morrow. When the dwelling had been sealed up by the
Wasp, I too would postpone my observations till the next day, but only
after first making a map of the ground, choosing my lines and landmarks
and planting a few stalks as signposts to show me the way to the well
when it was filled. If I did not come back very early in the morning,
if I left the Wasp time to take advantage of the hours of bright
sunshine, I invariably found the burrow finally stocked with provisions
and closed.

This faithfulness of memory is striking. The Wasp, delayed in her task,
puts off the rest of her work to the next day. She does not spend the
evening, she does not spend the night in the home which she has just
dug: on the contrary, she leaves the premises altogether and goes away,
after concealing the entrance with a little stone. The locality is not
familiar to her; she knows it no better than any other spot, for the
Ammophilæ behave like the Languedocian Sphex and lodge their families
here or there, wherever they happen to roam. The Wasp was there by
chance; the soil suited her; she dug her burrow; and she now goes off.
Where to? Who can tell? Perhaps to the flowers not far away, where, by
the last gleams of daylight, she will sip a drop of sugary liquid at
the bottom of the cups, even as our miners, after toiling in their dark
galleries, fly for comfort to the bottle in the evening. She goes off,
to a less or greater distance, stopping at this bin and that in the
flowers’ cellar. The evening, the night, the morning slip by. Still,
she must return to the burrow and complete her task, she must return
after the marches and countermarches of the morning hunt and the
bewildering flight from flower to flower during the libations of the
evening before. That the Social Wasp should return to her nest and the
Social Bee to her hive does not surprise me at all: the hive and the
nest are permanent residences, the way to which becomes known by long
practice; but the Ammophila has no acquaintance with the locality which
could help her to return to her burrow after such a long absence. Her
tunnel is at a spot which she perhaps visited yesterday for the first
time and which she must find again to-morrow, when she is quite out of
her bearings and moreover hampered with a heavy load of game.
Nevertheless, this little feat of topographical memory is performed,
sometimes with a precision that left me astounded. The Wasp would walk
straight to her burrow as if she had long been using all the little
paths in the neighbourhood. At other times she would wander backwards
and forwards and renew her search over and over again.

If the quest is greatly prolonged, the prey, which is a troublesome
burden when you are in a hurry to find your home, is laid down in some
high place, on a cluster of thyme or a tuft of grass, where it will be
well in sight presently, when wanted. Thus eased, the Ammophila resumes
her active search. I made a pencil-sketch, as she moved about, of the
tracks followed. The result was a medley of tangled lines, with sudden
bends and turns, branches in and branches out, windings and repeated
intersections—in short, a regular labyrinth whose complicated maze was
an ocular demonstration of the perplexity of the lost one.

When the well has been found and the slab removed, the Wasp has to come
back to the caterpillar, which is not always done without some groping
about, in cases where her wanderings to and fro have been very
numerous. Though she left her prey easily visible, the Wasp appears to
foresee the difficulty of finding it again when the moment comes to
drag it home. At least, if the search is unduly prolonged, you see her
suddenly interrupt her exploration of the ground and return to her
caterpillar, which she feels and nibbles at for a moment, as though to
make sure that it is really her own game, her property. Then she
hurries back again to the field of search, which she leaves a second
time, if need be, and a third, in order to inspect the prey. I am not
at all sure that these repeated visits of the Wasp to the caterpillar
are not a means of refreshing her memory of the place where she left
it.

This is what happens in exceedingly complicated cases; but as a rule
the Wasp goes back quite easily to the well dug the day before on the
spot to which chance has taken her. The vagabond’s guide is her
topographical memory, whose marvellous feats I shall have to tell
later. As for me, in order to return next day to the well hidden under
the lid of the little flat stone, I dared not trust to my unaided
memory: I needed notes, sketches, lines of latitude and longitude,
landmarks—in short, all the minutiæ of geometry.

The temporary closing of the burrow with a flat stone, as practised by
the Sandy Ammophila and the Silvery Ammophila, is apparently unknown to
the other two species. At any rate, I never saw their homes protected
by a lid. Besides, this absence of a provisional door seems to be
obligatory upon the Hairy Ammophila. In fact, as far as I could see,
this species hunts its prey first and then digs its burrow near the
place of capture. In this way the storing of the provisions can be done
straight away; and there is no need to trouble about a lid. As for the
Silky Ammophila, I suspect that she has another reason for not
employing a temporary cover. Whereas the three others put only one
caterpillar in each burrow, she puts in as many as five, though much
smaller ones. Just as we ourselves neglect to shut a door through which
we are constantly passing, so perhaps the Silky Ammophila neglects the
precaution of placing a stone over a well down which she has to go at
least five times in a short space of time.

In the case of all four, the provisions of the larvæ consist of
caterpillars of Moths. The Silky Ammophila selects, though not
exclusively, those long, thin caterpillars which walk by looping and
unlooping their bodies. Their gait suggests a pair of compasses that
makes its way by opening and closing in turns. Hence they are known by
two expressive names: Loopers and Measuring-worms. [32] The same burrow
contains provisions varying greatly in colour, a proof that the
Ammophila hunts without distinction every species of Loopers, provided
that they be small, for the huntress herself is anything but large and
her grub cannot get through very much, in spite of the five pieces of
game set before her. If Loopers fail, the Wasp falls back on other
equally slender caterpillars. Curved into a hoop as the result of the
sting that paralysed them, the five pieces are stacked up in the cell:
the uppermost carries the egg for which the provisions are made.

The three other Ammophilæ give only one caterpillar to each larva. It
is true that here bulk makes up for number: the game selected is big,
plump, capable of amply satisfying the grub’s appetite. For instance, I
have taken from the mandibles of the Sandy Ammophila a caterpillar
weighing fifteen times as much as its captor: fifteen times, an
enormous figure when we consider the strength which the huntress must
expend in dragging game of this kind by the skin of the neck over the
countless obstacles on the road. No other Wasp, tried in the balance
with her prey, has shown me a like disproportion between spoiler and
booty.

The almost indefinite variety of colouring in the provisions which I
unearth from the burrows or see between the legs of the Ammophilæ also
proves that the three brigands have no preference and pounce upon the
first caterpillar which comes along, provided that it be of a suitable
size, neither too large nor too small, and that it belongs to the Moth
division. The commonest game consists of those grey-clad caterpillars
which penetrate a little way into the ground and devour the plant at
the junction of root and stem.

What governs the whole history of the Ammophilæ and more particularly
attracted my attention is the manner in which the insect overpowers its
prey and reduces it to the condition of helplessness which the safety
of the larva requires. The game hunted, the caterpillar, possesses a
very different structure from that of the victims which we have seen
immolated hitherto: Buprestes, Weevils, Locusts and Ephippigers. The
creature is composed of a series of similar rings or segments set end
to end. Three of these segments, the first three, carry the real legs,
which will become the legs of the future Moth; others have membranous
legs, or pro-legs, which are peculiar to the caterpillar and not
represented in the Moth; others, lastly, have no limbs at all. Each
segment has its nerve-nucleus, or ganglion, the seat of sensibility and
movement, so that the nervous system includes twelve distinct centres,
separated one from the other, without counting the ganglionic
neck-piece placed under the skull and comparable, in a manner of
speaking, with the brain.

We are here very far removed from the nerve-centralization of the
Weevils and the Buprestes, which lends itself so well to general
paralysis by a single prick of the sting; we are also a long way from
the thoracic ganglia which the Sphex smites, one after the other, to
suppress all movement in her Crickets. Instead of a solitary
centralized point or of three nerve-nuclei, the caterpillar has twelve,
separated from one another by the distance between one segment and the
next and arranged like a string of beads on the ventral surface, along
the median line of the body. Moreover, as is the general rule in the
lower animals, where the same organ is repeated a great number of times
and loses power by its diffusion, these different nerve-centres are
largely independent of one another: each of them exercises its
influence over its particular segment; and its functions are only very
gradually affected by the derangement of the adjoining segments. One of
the caterpillar’s rings can lose its power of moving and feeling and
the remainder will nevertheless remain capable of both for a
considerable time. These facts are enough to show the great interest
attaching to the methods of slaughter which the Wasp adopts with her
prey.

But, while the interest is great, the difficulty of observation is not
small. The solitary habits of the Ammophilæ, their distribution one by
one over wide areas, the fact that one almost always comes across them
merely by chance: all this makes it hardly possible to carry out
premeditated experiments with them, anymore than with the Languedocian
Sphex. You have to be on the look-out a long time for an opportunity,
to wait for it with untiring patience, and to know how to profit by it
at the very moment when at last it presents itself, a moment when you
were not thinking of it. I watched for that opportunity for years and
years; then one day it suddenly appeared before my eyes, offering a
facility of examination and a clearness of detail that compensated me
for my long waiting.

At the beginning of my investigations I was twice enabled to witness
the murder of the caterpillar, and I saw, as far as the swiftness of
the operation permitted, the Wasp’s sting applied once and for all to
either the fifth or the sixth segment of the victim. To confirm this
result, I thought of ascertaining which ring had been stabbed on
caterpillars which I had not seen sacrificed, but which I had taken
from their captors while they were being dragged to the burrow. It was
no use employing a magnifying-glass, for no magnifying-glass enables
one to discover the least trace of a wound upon the victim. The method
adopted is the following: when the caterpillar is quite still, I try
each segment with the point of a fine needle and thus measure the
amount of sensibility by the more or less manifest signs of pain in the
insect. When the needle pricks the fifth segment or the sixth, even
piercing it right through, the caterpillar does not stir. But if you
prick even slightly a second segment, behind or in front of that
insensible segment, the caterpillar wriggles and struggles with a
violence which increases in proportion to the distance of the point
attacked from the original segment. At the hinder end in particular,
the least touch provokes wild contortions. There was only one sting,
therefore, and it was administered to the fifth or sixth ring.

What peculiarity then do these two segments possess that one or other
of them should be the target of the assassin’s weapon? None whatever in
their organization; but their position is another matter. Leaving the
Silky Ammophila’s Measuring-worms on one side, I find that the prey of
the others is organized as follows, the head being counted as the first
segment: three pairs of real legs on the second, third and fourth
rings; four pairs of membranous legs on the seventh, eighth, ninth and
tenth rings; lastly, a final pair of membranous legs on the thirteenth
and last ring, making in all eight pairs of legs, of which the first
seven form two vigorous groups, one of three, the other of four pairs.
These two groups are separated by two legless segments, which are
precisely the fifth and sixth.

Now, in order to deprive the caterpillar of its means of escape, to
render it motionless, will the Wasp drive her sting into each of the
eight rings provided with locomotory organs? Above all, will she take
this superfluity of precaution when the prey is quite weak and small?
Certainly not: a single stab will be enough; but it will be given at a
central point, whence the torpor produced by the tiny drop of poison
can spread gradually, with the least possible delay, to the segments
furnished with legs. There is no doubt about the segment to be picked
out for this single inoculation: it must be the fifth or the sixth,
which separate the two groups of locomotory rings. The point indicated
by rational inferences is therefore also the point adopted by instinct.

Lastly, let us add that the Ammophila’s egg is invariably laid on the
ring that has been rendered insensible. Here and here alone the young
larva can bite without provoking dangerous contortions; where a
needle-prick has no effect, the grub’s bite will have no effect either.
The grub will thus remain motionless until the nurseling has gained
strength and can forge ahead without running a risk.

In my later researches, as the number of my observations increased, I
began to entertain doubts, not as to the conclusions which I had
formed, but as to their general application. That feeble Loopers and
other small caterpillars are rendered harmless by a single thrust,
especially when the sting strikes the favourable spot described, is a
thing quite probable in itself and one which can also be proved either
by direct observation or by testing the insect’s sensibility with a
needle. But the Sandy Ammophila and especially the Hairy Ammophila
capture enormous victims, whose weight, as I have said, is fifteen
times that of the kidnapper. Will this giant prey be treated in the
same manner as the frail Measuring-worm? Will one dagger-thrust be
sufficient to subdue the monster and render it incapable of doing harm?
Will the horrid Grey Worm, lashing the walls of the cell with its
powerful tail, not endanger either the egg or the little grub? We dare
not picture the encounter, in the narrow cell of the burrow, between
those two—the feeble, new-hatched creature and that dragony thing still
possessing freedom in its movements to twist and untwist its tortuous
coils.

My suspicions were confirmed by an examination of the caterpillar from
the point of view of sensibility. Whereas the small game of the Silky
Ammophila and the Silvery Ammophila struggle violently if the needle
touches them elsewhere than in the ring stung by the Wasp, the big
caterpillars of the Sandy Ammophila and especially of the Hairy
Ammophila remain motionless, no matter which segment we prick. With
them there are no contortions, no sudden twists of the hinder parts;
the steel point produces no sign of a remnant of sensibility beyond a
faint quivering of the skin. The power of moving and feeling is
therefore almost wholly abolished, as it needs must be if the grub is
to feed in safety on this monstrous prey. Before placing it in the
burrow, the Wasp has turned it into an inert though still living mass.

I have been permitted to watch the Ammophila operating with her scalpel
on the sturdy caterpillar, and never did the intuitive science of
instinct show me anything more exciting. With a friend—soon, alas, to
be snatched from me by death!—I was coming back from the plateau of Les
Angles to lay snares for the Sacred Beetle and put his skill to the
test, when we caught sight of a Hairy Ammophila very busily employed at
the foot of a tuft of thyme. We at once lay down on the ground, close
to where she was working. Our presence did not frighten the Wasp; in
fact, she came and settled on my sleeve for a moment, decided that her
two visitors were harmless, since they did not move, and returned to
her tuft of thyme. As an old stager, I knew what that daring
familiarity meant: the Wasp’s attention was occupied with a serious
business. We would wait and see.

The Ammophila scratched the ground at the foot of the plant, at the
junction of root and stem, pulled up slender grass rootlets and poked
her head under the little clods which she had lifted. She ran hurriedly
this way and that around the thyme, inspecting every crevice that could
give access to what lay below. She was not digging herself a home but
hunting some game hidden underground; this was evident from her
behaviour, which resembled that of a Dog trying to dig a Rabbit out of
his hole. Presently, excited by what was happening overhead and
close-pressed by the Ammophila, a big Grey Worm made up his mind to
leave his lair and come up to the light of day. That settled him; the
huntress was on the spot at once, gripping him by the skin of his neck
and holding tight in spite of his contortions. Perched on the monster’s
back, the Wasp bent her abdomen and deliberately, without hurrying,
like a surgeon thoroughly acquainted with his patient’s anatomy, drove
her lancet into the ventral surface of each of the victim’s segments,
from the first to the last. Not a ring was left without receiving a
stab; all, whether with legs or without, were dealt with in order, from
front to back.

That is what I saw with all the leisure and ease that an observation
needs in order to be above reproach. The Wasp acts with a precision
that would make science turn green with envy; she knows what man hardly
ever knows; she knows her victim’s complex nervous system and reserves
her successive dagger-thrusts for the successive ganglia of her
caterpillar. I said, she knows; what I should say is, she behaves as
though she knew. Her act is simple inspiration. Animals obey their
compelling instinct, without realizing what they do. But whence comes
that sublime inspiration? Can theories of atavism, of natural
selection, of the struggle for life interpret it reasonably? To me and
my friend, this was and remained one of the most eloquent revelations
of the unutterable logic that rules the world and guides the ignorant
by the laws of its inspiration. Stirred to our innermost being by this
flash of truth, both of us felt tears of undefinable emotion spring to
our eyes.



CHAPTER XIV

THE BEMBEX


One of my favourite spots for the observations which I will now
describe is not far from Avignon, on the right bank of the Rhône,
opposite the mouth of the Durance. It is the Bois des Issarts. Let not
the reader mistake the value of this word bois, which usually suggests
a carpet of cool moss and the shade of tall trees, with a dim light
filtering through the leaves. The scorched plains where the Cicada
grates out his ditty on the pale olive-tree know none of these
delicious retreats filled with cool shadow.

The Bois des Issarts is a coppice of holm-oaks no higher than one’s
head and sparingly distributed in scanty clumps which, even at their
feet, hardly temper the force of the sun’s rays. When I used to settle
myself in some part of the coppice suitable for my observations, on
certain afternoons in the dog-days of July and August, I had the
shelter of a large umbrella, which later, in the most unexpected
fashion, lent me a very precious aid of a different kind, as my story
will show in good time. If I neglected to furnish myself with this
embarrassing adjunct to a long walk, my only resource against sunstroke
was to lie down at full length behind some sandy knoll; and, when the
veins in my temples were throbbing to bursting point, my last hope lay
in putting my head down a Rabbit-burrow. Such are one’s means of
keeping cool in the Bois des Issarts.

The soil not occupied by those clumps of woody vegetation is almost
bare and consists of fine, dry, very loose sand, which the wind heaps
into little dunes wherever the stems and roots of the holm-oak
interfere with its dissemination. The sides of these sand-dunes are
generally very smooth, because of the extreme lightness of the
materials, which slide down into the smallest depression and of their
own accord restore the evenness of the surface. You need but push your
finger into the sand and take it out again to bring about an immediate
landslip which fills up the hole and restores things to their original
condition without leaving a visible trace. But, at a certain depth,
which varies according to the more or less recent date of the last
rains, the sand retains a lingering dampness which keeps it in its
place and gives it a consistency that enables it to have small
excavations made in it without a subsequent collapse of walls and roof.
A blazing sun, a gloriously blue sky, sandy slopes that yield without
the least difficulty to the strokes of the Wasp’s rake, game galore for
the grub’s food, a peaceful site hardly ever disturbed by the foot of
man: all the good things are combined in this Bembex paradise. Let us
watch the industrious insect at work.

If the reader will sit with me under the umbrella, or consent to share
my Rabbit-burrow, this is the sight which he is invited to behold, at
the end of July: a Bembex (B. rostrata) arrives suddenly, I know not
whence, and alights, without preliminary investigations or the least
hesitation, at a spot which to my eyes differs in no respect from the
rest of the sandy surface. With her fore-tarsi, which are armed with
rows of stiff hairs and suggest at the same time a broom, a brush and a
rake, she works at clearing her subterranean dwelling. The insect
stands on its four hind-legs, holding the two at the back a little wide
apart, while the front ones alternately scratch and sweep the shifting
sand. The precision and quickness of the performance could not be
greater if the circular movement of the tarsi were worked by a spring.
The sand, shot backwards under the abdomen, passes through the arch of
the hind-legs, gushes like a fluid in a continuous stream, describes
its parabola and falls to the ground some seven or eight inches away.
This spray of dust, kept up evenly for five or ten minutes at a time,
is enough to show the dazzling rapidity of the tools employed. I know
no other example of this swiftness, which nevertheless in no way
detracts from the easy grace and the free movement of the insect, as it
advances and retires first on this side, then on that, without
discontinuing its parabolic streams of sand.

The soil excavated is of the lightest kind. As the Wasp digs, the sand
near by slips back and fills the cavity. Amongst the rubbish that falls
are tiny bits of wood, decayed leaf-stalks and particles of grit larger
than the rest. The Bembex takes them up in her mandibles and carries
them away, moving backwards as she goes; then she returns to her
sweeping, but never going to any length and making no attempt to bury
herself underground. What is her object in thus labouring entirely on
the surface? It would be impossible to tell from this first glance;
but, after spending many days with my beloved Wasps and grouping
together the scattered facts resulting from my observations, I seem to
catch a glimpse of the reason for the present proceedings.

The Wasp’s nest is certainly there, a few inches below the ground; in a
little cell dug in the cool, firm sand lies an egg, perhaps a grub for
which the mother caters from day to day, bringing it Flies, the
unvarying food of the Bembex in their first state. The mother has to be
able at any moment to enter the nest, as she flies up carrying in her
legs the nurseling’s daily portion of game, even as the bird of prey
enters its eyrie with the food for its young in its talons. But, while
the bird returns to a home on some inaccessible ledge of rock, with no
difficulty to overcome but that of the weight and encumbrance of the
captured prey, the Bembex has each time to undertake rough miner’s work
and open up anew a gallery blocked and closed by the mere fact that the
sand gives way as the insect proceeds. In that underground dwelling,
the only room with steady walls is the spacious cell where the larva
lives amid the remnants of its fortnight’s feast; the narrow corridor
which the mother enters to reach the flat at the back or to come out
and go hunting collapses each time, at least in the front part dug out
of very dry sand, which repeated exits and entrances make looser still.
Each time therefore that the Wasp goes in or out, she has to clear
herself a passage through the débris.

Going out presents no difficulty, even should the sand retain the
consistency which it might have at the start, when first disturbed: the
insect’s movements are free, it is safe under cover, it can take its
time and use its tarsi and mandibles without undue hurry. Going in is a
very different matter. The Bembex is hampered by her prey, which her
legs hold clasped to her body; and the miner is thus deprived of the
free use of her tools. And a still graver circumstance is this: brazen
parasites, veritable bandits in ambush, crouch here and there in the
neighbourhood of the burrow, spying on the mother Wasp as she makes her
laborious entrance, so that they may rush in and lay their egg on the
piece of game at the very moment when it is about to disappear down the
corridor. If they succeed, the Wasp’s nurseling, the son of the house,
will perish, starved by its gluttonous fellow-boarders.

The Bembex seems aware of these dangers and makes arrangements for her
entrance to be effected swiftly, without serious obstacles—in short,
for the sand blocking the door to yield to a mere push of her head,
aided by a brisk sweep of her front tarsi. With this object, the
material at the approaches to the home are subjected to a sort of
sifting. At leisure moments, under a kindly sun, when the larva has its
food and does not need her attentions, the mother rakes the ground in
front of her door; she removes little bits of wood, any extra-large
particles of gravel, any leaves that might get in the way and bar her
passage at the dangerous moment of her return. The Bembex whom we have
just seen so zealously employed was busy at this work of sifting: to
facilitate the access to her home, the materials of the corridor have
to be dug up, carefully sorted and rid of anything likely to obstruct
the road. Who indeed can tell whether, by that nimble eagerness, that
joyous activity, the insect is not expressing in its own way its
maternal satisfaction, its happiness in watching over the roof of the
cell to which the precious egg has been entrusted?

As the Wasp is confining herself to her duties outside the house,
without trying to penetrate into the sand, everything must be in order
inside and there is no hurry about anything. We should only wait in
vain: the insect would tell us nothing more for the time being. Let us
therefore examine the underground dwelling. If we scrape the dune
lightly with the blade of a knife at the point where the Bembex was
busiest, we soon discover the entrance-corridor, which, though blocked
for part of the way down, is nevertheless recognizable by the
distinctive appearance of the materials moved. This passage, which is
as wide as one’s finger and straight or winding, longer or shorter
according to the nature and the accidents of the ground, measures eight
to twelve inches. It leads to a single chamber, hollowed in the damp
sand, whose walls are not coated with any kind of mortar likely to
prevent a subsidence or to lend a polish to the rough surface. The
ceiling will do, if it can hold out while the larva is growing up; it
does not matter what falls in afterwards, when the larva is enclosed in
its stout cocoon, a sort of safe which we shall see it building. The
workmanship of the cell, therefore, is very rustic: the whole thing is
reduced to a rough excavation, of no definite shape, with a low roof
and space enough to contain two or three walnuts.

In this retreat lies a piece of game, one only, quite small and quite
insufficient for the greedy nurseling which it is meant to feed. It is
a golden-green Fly, a Green-bottle (Lucilia Cæsar), [33] who lives on
putrid flesh. The Fly served up as food is absolutely motionless. Is
she quite dead, or only paralysed? This question will be cleared up
later. For the moment we will note the presence, on the side of the
game, of a cylindrical egg, white, very slightly curved and a couple of
millimetres [34] long. It is the egg of the Bembex. As we expected from
the mother’s behaviour, there is nothing urgent indoors: the egg is
laid and provided with a first ration apportioned to the requirements
of the feeble grub which will hatch twenty-four hours hence. The Bembex
had no need to re-enter the underground passage for some time and was
confining herself to keeping a good look-out all round, or perhaps to
digging fresh burrows and continuing to lay her eggs, one by one, each
in a cell to itself.

This peculiarity of beginning the provisioning with a single head of
small game is not confined to the Rostrate Bembex. All the other
species do the same thing. If we open the cell of any Bembex shortly
after the egg is laid, we shall always find the tiny cylinder glued to
the side of a Fly, who constitutes the entire provision; moreover, this
initial ration is invariably small, as though the mother went in search
of the tenderest mouthfuls for the feeble nurseling. Besides, another
reason, the abiding freshness of the food, might easily prompt her to
make this choice. We will look into that later. This first portion,
always a scanty one, varies greatly in nature, according to the
frequency of this or that kind of game in the neighbourhood of the
nest. It is sometimes a Green-bottle, sometimes a Stomoxys, or some
small Eristalis, sometimes a dainty Bee-fly clad in black velvet; but
the most usual dish is a slim-bellied Sphærophoria.

This general fact, to which there is no exception, of the victualling
of the egg with a single Fly, a ration infinitely too small for a larva
blessed with a voracious appetite, at once puts us on the track of the
most remarkable habit of the Bembex. Wasps whose larvæ live on prey
heap up in each cell the number of victims necessary for the rearing of
the grub; they lay the egg on one of the bodies and close the dwelling,
which they do not enter again. From that moment the larva hatches and
develops alone, having before it from the very beginning the whole
stock of provisions which it is to consume. The Bembex form an
exception to this rule. The cell is first stocked with a single head of
game, always small in size, and the egg is laid on it. When that is
done, the mother leaves the burrow, which closes of itself; besides,
before going away, the insect is careful to rake over the outside, so
as to smooth the surface and hide the entrance from any eye but her
own.

Two or three days elapse; the egg hatches and the little larva eats up
the choice ration served to it. Meanwhile the mother remains in the
neighbourhood and you see her sometimes feeding herself by sipping the
sugary exudations of the field eringo, sometimes settling happily on
the burning sand, no doubt watching the outside of the house. Every now
and again she sifts the sand at the entrance; then she flies away and
disappears, perhaps to dig other cells elsewhere and to stock them in
the same way. But, however long she may stay away, she never forgets
the young larva so scantily provided for; the instinct of a mother
tells her the hour when the grub has finished its food and is calling
for fresh nourishment. She therefore returns to the nest, of which she
is wonderfully capable of discovering the invisible entrance; she goes
down into the earth, this time carrying a bulkier piece of game. After
depositing her prey, she again leaves the house and waits outside till
the moment arrives to serve a third course. This moment is not slow in
coming, for the larva devours its food with a lusty appetite. Again the
mother appears with fresh provisions.

During nearly a fortnight, while the larva is growing up, the meals
thus follow in succession, one by one, as needed, and coming closer
together as the nurseling waxes bigger. Towards the end of the
fortnight it takes all the mother’s activity to satisfy the appetite of
the glutton, who crawls heavily along with his great lumbering belly,
amid the scorned leavings: rejected wings and legs and horny abdominal
segments. You see her at every moment returning with a recent capture,
at every moment setting out again upon the chase. In short, the Bembex
brings up her family from day to day, without storing up provisions in
advance, just as the bird does, which feeds its nestlings from hand to
mouth. Of the many proofs that are evidence of this method of
upbringing, a very singular method for a Wasp who feeds her offspring
on prey, I have already mentioned the presence of the egg in a cell
containing no provisions but one small Fly, never more. And here is
another one, which can be verified at any time.

Let us look into the burrow of a Wasp who stocks her grubs’ provisions
in advance: if we select the moment when the insect is going in with
its prey, we shall find in the cell a certain number of victims, the
commencement of a larder, but never at that time a grub, nor even an
egg, for this is not laid until the provisions are quite complete. When
the egg is laid, the cell is closed and the mother does not return to
it. It is therefore only in burrows where the mother’s visits are no
longer necessary that we can find larvæ side by side with larger or
smaller stocks of food. On the other hand, let us inspect the home of a
Bembex at the moment when she is entering with the fruits of her
hunting. We are certain of finding in the cell a larva, big or little
as the case may be, among remnants of provisions already consumed. The
portion which the mother is now bringing is therefore intended to
prolong a meal which has already lasted several days and which is to
continue for some time further with the produce of future hunting
expeditions. Should we be fortunate enough to make this search towards
the end of the larva’s infancy—an advantage which I have enjoyed as
often as I wished to—we shall find, on a copious heap of remnants, a
large and portly grub, to which the mother is still bringing fresh
victuals. The Bembex does not cease her catering and does not leave the
cell for good until the larva, distended by a purply paste, refuses its
food and lies down, stuffed to repletion, on the jumble of legs and
wings of the game which it has devoured.

Each time that the mother enters the burrow on returning from the
chase, she brings but a single Fly. If it were possible, by counting
the remnants contained in a cell whose occupant is full-grown, to tell
the number of victims supplied to the larva, we should know how often
at the least the Wasp visited her burrow after laying the egg.
Unfortunately, these broken victuals, chewed and chewed again at
moments of scarcity, are for the most part unrecognizable. But, if we
open a cell with a less forward nurseling, the provisions lend
themselves to examination, some of them being still whole or nearly
whole, while others, more numerous, are represented by fragments in a
state of preservation that enables them to be identified. Incomplete
though it be, the list obtained under these conditions is surprising
and shows what activity the Wasp must display to satisfy the needs of
such a table. I will set forth one of the bills of fare which I have
observed.

At the end of September, around the larva of a Jules’ Bembex (Bembex
Julii), [35] which has reached almost a third of the size which it will
finally attain, I find the following heads of game: six Echinomyia
rubescens (two whole and four in pieces); four Syrphus corollæ (two
complete, the other two broken up); three Gonia atra (all three
untouched: one of them had that moment been brought along by the
mother, which led to my discovering the burrow); two Pollenia rufescens
(one untouched, the other partly eaten); one Bombylius (reduced to
pulp); two Echinomyia intermedia (in bits); and two Pollenia floralis
(likewise in bits): twenty pieces in all. This certainly makes a both
plentiful and varied bill of fare; but, as the larva was only a third
of its ultimate size, the complete menu might easily number as many as
sixty items.

It is not at all difficult to verify this sumptuous figure: I will
myself take the place of the Bembex in her maternal functions and
supply the larva with food till it is ready to burst. I move the cell
into a little cardboard box which I furnish with a layer of sand. I
place the larva on this bed, with all due consideration for its
delicate skin. Around it, without omitting a single fragment, I arrange
the provisions with which it was supplied. Then I go home, still
holding the box in my hand, to avoid any shaking which might turn the
house upside down and endanger my charge during a walk of several
miles. Any one who had met me on the dusty Nîmes Road, dropping with
fatigue and religiously carrying in my hand, as the sole fruit of my
laborious trip, an ugly grub battening on a heap of Flies, would
certainly have smiled at my simplicity.

The journey was effected without damage: when I reached home, the larva
was placidly eating its Flies as though nothing had happened. On the
third day of captivity the provisions taken from the burrow were
finished; the grub was rummaging with its pointed mouth among the heap
of remains without finding anything to suit it; the dry particles taken
hold of, all horny, juiceless bits, were rejected with disgust. The
moment has come for me to continue the food supply. The first Flies
within reach shall form my prisoner’s diet. I kill them by pressing
them in my fingers, but without crushing them. The first ration
consists of three Eristalis tenax and one Sarcophaga. [36] This is all
gobbled up in twenty-four hours. Next day I provide two Eristales, or
Drone-flies, and four House-flies. It was enough for the day, but left
nothing over. I went on like this for eight days, giving the grub a
larger portion every morning. On the ninth day the larva refused all
food and began to spin its cocoon. The full record of this eight days’
feast amounts to sixty-two pieces, composed mainly of Drone-flies and
House-flies, which, added to the twenty items found whole or in pieces
in the cell, brings up the total to eighty-two.

It is possible that I did not rear my larva with the wholesome
frugality and the wise economy which the mother would have shown; there
was perhaps some waste in the daily provisions served all at one time
and left entirely to the grub’s discretion. In some respects I feel
inclined to believe that things do not happen just like that in the
maternal cell, for my notes contain such details as the following. In
the alluvial sands of the Durance I discover a burrow which the Wasp
(Bembex oculata) has just entered with a Sarcophaga agricola. Inside I
find a larva, numerous fragments and a few whole Flies, namely, four
Sphærophoria scripta, one Onesia viarum and two Sarcophaga agricola,
including the one which the Bembex has just brought along before my
eyes. Now it is worthy of remark that half of this game, namely, the
Sphærophoriæ, is right at the end of the cell, under the larva’s very
teeth, whereas the other half is still in the passage, on the threshold
of the cell, and therefore beyond the reach of the grub, which is
unable to change its position. It seems to me then that, when game is
plentiful, the mother lays her captures on the threshold of the cell
for the time and forms a reserve on which she draws as and when
necessary, especially on rainy days when all labour is at a standstill.

Thus practised with economy, the distribution of food would save a
waste which I was not able to prevent with my larva, treated I dare say
too sumptuously. I therefore lower the figure obtained and reduce it to
some sixty pieces, of middling size, between that of the House-fly and
of the Eristalis tenax. This would about represent the number of Flies
supplied by the mother to the larva when the prey is of a moderate
size, as is the case with all the Bembex of my district except the
Rostrate Bembex (B. rostrata) and the Two-pronged Bembex (B.
bidentata), who have a preference for Gad-flies. With them, the number
of victims would be from one to two dozen, according to the size of the
Fly, which varies greatly in the different species of Gad-flies.

To avoid reopening this question of the nature of the provisions, I
will here give a list of the Flies observed in the burrows of the six
species of Bembex that form the subject of this essay.

1. Bembex olivacea, Rossi. I only once saw this species, at Cavaillon,
feeding on Green-bottles. The five other species are common in the
Avignon neighbourhood.

2. Bembex oculata, Jur. The Fly carrying the egg is most often a
Sphærophoria, especially S. scripta; sometimes it is a Geron gibbosus.
The later provisions include Stomoxys calcitrans, Pollenia ruficollis,
P. rudis, Pipiza nigripes, Syrphus corollæ, Onesia viarum, Calliphora
vomitoria, [37] Echinomyia intermedia, Sarcophaga agricola and Musca
domestica. [38] The usual fare consists of Stomoxys calcitrans, of
which I have many a time found fifty or sixty in a single burrow.

3. Bembex tarsata, Lat. This one also lays her egg on Sphærophoria
scripta. She next hunts: Anthrax flava, Bombylius nitidulus, Eristalis
æneus, E. sepulchralis, Merodon spinipes, Syrphus corollæ, Helophilus
trivittatus and Zodion notatum. Her favourite game consists of
Bombylii, or Bee-flies, and Anthrax-flies. [39]

4. Bembex Julii (sp. nov.). The egg is laid on a Sphærophoria or on a
Pollenia floralis. The provisions are a hotchpotch of Syrphus corollæ,
Echinomyia rubescens, E. intermedia, Gonia atra, Pollenia floralis, P.
ruficollis, Clytia pellucens, Lucilia Cæsar, Dexia rustica and
Bombylius.

5. Bembex rostrata, Fab. This is preeminently a consumer of Gad-flies.
She lays her egg on a Syrphus corollæ or a Lucilia Cæsar, after which
she feeds her larva exclusively on big game belonging to the various
species of the genus Tabanus.

6. Bembex bidentata, V. L. Another ardent huntress of Gad-flies. I have
never seen her pursue other game and I do not know on what Fly the egg
is laid.

This great variety of provisions shows that the Bembex have no
exclusive tastes and fall upon any species of Flies, indifferently,
which the hazards of the chase place within their reach. They seem
nevertheless to entertain a few preferences. Thus one species feeds
more particularly on Bee-flies, a second on Stomoxys-flies, a third and
a fourth on Gad-flies.



CHAPTER XV

THE FLY-HUNT


After our list, in the last chapter, of the fare on which the Bembex
feed in the larval form, it behoves us to seek the motive that induces
these Wasps to adopt a method of victualling so exceptional among the
digger-insects. Why, instead of previously storing a sufficient
quantity of provisions on which the egg could be laid—which would
enable the mother to close the cell immediately afterwards and never to
return to it—why, I ask, does she tie herself down for a fortnight to
this incessant, toilsome coming and going from the burrow to the fields
and from the fields to the burrow, forcing her way each time through
the unstable sand, either to go hunting or to bring the larva her
latest capture? It is, first and foremost, a question of having fresh
victuals for her larva: an all-important question, for the grub
absolutely refuses any high or tainted game. Like the grubs of the
other Diggers, it wants fresh meat and nothing but fresh meat.

We have seen in the case of the Cerceres, the Sphex and the Ammophilæ
how the mother solves the problem of preserved food-stuffs, the problem
of stocking a cell with the requisite quantity of game for its future
occupant and keeping the meat fresh for whole weeks at a time; indeed,
it is something more than fresh, for the victims are kept in an almost
living state, except that they are incapable of movement, an essential
condition if the grub is to feed on them in safety. The miracle is
performed by the most cunning methods known to physiology. The poisoned
lancet is driven into the nerve-centres once or oftener, according to
the structure of the nervous system. Thus operated upon, the victim
retains all the attributes of life, short of the power of moving.

Let us see if the Bembex make use of this profound science of
slaughter. The Flies taken from between the legs of the kidnapper as
she enters her burrow present, in most cases, every appearance of
death. They are motionless; occasionally we can detect in a few of them
some faint convulsions of the tarsi, the last vestiges of a life that
is passing away. The same appearance of complete death is usually found
in the insects which are not actually killed but paralysed by the
adroit dagger-thrust of a Cerceris or a Sphex. The question whether
they are alive or dead can therefore be decided only according to the
manner in which the victims keep fresh.

Placed in little screws of paper or in glass tubes, the Crickets and
Grasshoppers of the Sphex, the caterpillars of the Ammophilæ, and the
Beetles and Weevils of the Cerceres preserve their flexibility of limb,
their freshness of colouring and the normal condition of their
intestines for weeks and months. They are not corpses but bodies sunk
in a lethargy from which there is no awaking. The Flies of the Bembex
behave quite differently. The Eristales, the Syrphi—in short, all those
whose livery is at all brightly coloured—soon lose the brilliancy of
their attire. The eyes of certain Gad-flies, magnificently gilded, with
three purple bands, very quickly grow pale and dim, like the eyes of a
dying man. All these Flies, large and small, when placed in little
paper bags through which the air circulates freely, dry up in two or
three days and become brittle; all, when preserved against evaporation
in glass tubes in which the air is stationary, go mouldy and decay.
They are dead, therefore, really and truly dead, when the Wasp brings
them to her larva. Should some of them still retain a remnant of life,
a few days or even hours put an end to their agony. Consequently, for
lack of talent in the use of her dagger or for some other reason, the
murderess kills her victims outright.

In view of this fact, that the prey is quite dead at the moment when it
is carried off, who would not admire the logic of the Bembex’
procedure? How methodical and consistent everything is in the actions
of the cunning Wasp! As the provisions cannot keep beyond two or three
days without going bad, they must not be stored entire in the first
stages of an infancy which will last at least a fortnight; and the
hunting and distribution must necessarily be done day by day, bit by
bit, as the larva grows up. The first ration, the one that receives the
egg, will last longer than the others; the budding grub will take
several days to eat its flesh. It must therefore be small, otherwise
the joint would begin to putrefy before it was all finished. This joint
therefore will not be a bulky Gad-fly or a corpulent Bombylius, but
rather a tiny Sphærophoria, or something similar, making a dainty meal
for the larva which is still so delicate. Later, getting bigger and
bigger in time, will come the larger joints of venison.

The burrow must be kept shut during the mother’s absence, to save the
larva from regrettable intrusions; nevertheless the entrance must be
one that can be opened very frequently and hurriedly, without much
difficulty, when the Wasp returns laden with her prey and watched by
the sharp eyes of daring parasites. These conditions could not be
obtained with a compact soil such as that in which the Digger-wasps
usually make their abodes: the door, left to itself, would stay open;
and so, each time, there would be the long and toilsome job of either
blocking up the entrance with earth and gravel or unblocking it, as the
case might be. The house therefore must be dug in ground with a very
loose surface, in fine dry sand, which will at once yield to the
slightest effort on the mother’s part and, as it slides down, will
close the door of its own accord, like a curtain which, when you thrust
it aside with your hand, lets you pass through and then falls back
again. There you have the series of actions as deduced by man’s reason
and as practised by the Wasp’s sagacity.

Why does the spoiler kill the captured prey instead of simply
paralysing it? Is it for want of skill in the use of her sting? Is it
because of some difficulty due to the structure of the Flies or to the
methods employed in the chase? I must begin by confessing that I have
failed in my attempts to place Flies, without killing them, in that
state of complete immobility to which it is so easy to reduce a
Buprestis, a Weevil or a Scarab by injecting a tiny drop of ammonia
with a needle into the thoracic ganglia. In making the experiment, it
is difficult to render the insect motionless; and, by the time that it
has ceased to move, death has actually occurred, as is proved by its
speedy corruption or desiccation. But I have too much confidence in the
resources of instinct and have witnessed the ingenious solution of too
many problems to believe that a difficulty which baffles the
experimenter can bring the insect to a standstill. Therefore, without
throwing doubt upon the Bembex’ talents as a slaughterer, I should be
inclined to look for other reasons.

Perhaps the Fly, so thinly covered, so devoid of any plumpness, in a
word, so lean, could not, if paralysed by the sting, resist evaporation
long enough and would shrivel up during the two or three weeks of
waiting. Consider the puny Sphærophoria, the larva’s first mouthful.
How much liquid has that body to satisfy the needs of evaporation? An
infinitesimal drop, a mere nothing. The abdomen is a thin strip; its
two sides touch. Can such game as this form the basis of preserved
food, seeing that evaporation would dry up its juices in a few hours
when these are not renewed by nutrition? It is doubtful, to say the
least.

Let us examine the method of hunting, so as to throw some final light
on the subject. In the quarry removed from between the legs of the
Bembex, it is not rare to observe signs of a hurried capture, made
anyhow, according to the chances of a rough-and-tumble fight. The Fly
sometimes has her head turned the wrong way round, as though the
spoiler had wrung her neck; her wings are crushed; her fur, when she
possesses any, is ruffled. I have seen some that had their bellies
ripped open by their assailant’s mandibles and had lost their legs in
the battle. As a rule, however, the victim is intact.

No matter: considering the nature of the game, endowed with good wings
for flying, the capture must take place with a suddenness that makes it
hardly possible, I should say, to obtain paralysis unaccompanied by
death. A Cerceris face to face with her clumsy Weevil, a Sphex
grappling with the fat Cricket or the portly Ephippiger, an Ammophila
holding her caterpillar by the skin of its neck, all three have an
advantage over a prey which is too slow in its movements to avoid
attack. They can take their time, select at their ease the mathematical
spot where the sting is to penetrate, and lastly go to work with the
precision of an anatomist probing with his scalpel the patient who lies
before him on the operating-table. But with the Bembex it is a very
different matter: at the least alarm, the game nimbly makes off; and,
once on the wing, it can defy its pursuer. The Wasp has to pounce upon
her prey unawares, without considering how she shall attack or
calculating her blows, just as the Goshawk does when hunting in the
fallows. Mandibles, claws, sting, every weapon must be employed
simultaneously in the fierce fray so as to put an end as early as
possible to a contest in which the least hesitation would give the
victim time to escape. If these conjectures are borne out by the facts,
the Bembex’ prize can be nothing but a corpse or at most a mortally
wounded prey.

Well, my conjectures are correct: the Bembex delivers her attack with a
dash which would do credit to a bird of prey. To surprise the Wasp
hunting is not an easy thing; were we never so well armed with
patience, we should watch in vain in the neighbourhood of the burrow:
the favourable opportunity would not present itself, for the insect
flies far away and there is no possibility of following it in its rapid
evolutions. Its tactics would doubtless be unknown to me but for the
assistance of a utensil from which I would certainly never have
expected such a service. I am speaking of my umbrella, which I used as
a protection against the sun in the sand of the Bois des Issarts.

I was not the only one to profit by its shade; I was generally
surrounded by numerous companions. Gad-flies of various species would
take refuge under the silken dome and sit peacefully on every part of
the tightly-stretched cover. I was rarely without their society when
the heat became overpowering. To while away the hours when I had
nothing to do, it amused me to watch their great gold eyes, which shone
like carbuncles under my canopy; I loved to follow their solemn
progress when some part of the ceiling became too hot and obliged them
to move a little way on.

One day, bang! The tight cover resounded like the skin of a drum.
Perhaps an oak had dropped an acorn on the umbrella. Presently, one
after the other, bang, bang, bang! Can some practical joker have come
to disturb my solitude and fling acorns or little pebbles at my
umbrella? I leave my tent and inspect the neighbourhood: nothing! The
same sharp sound is repeated. I look up at the ceiling, and the mystery
is explained. The Bembex of the vicinity, who all consume Gad-flies,
had discovered the rich provender that was keeping me company and were
impudently penetrating my shelter to seize the Flies on the ceiling.
Things were going to perfection: I had only to sit still and look.

Every moment a Bembex would enter, swift as lightning, and dart up to
the silken ceiling, which resounded with a sharp thud. Some rumpus was
going on aloft, where the eye could no longer distinguish between
attacker and attacked, so lively was the fray. The struggle did not
last for an appreciable time: the Wasp would retire forthwith with a
victim between her legs. The dull herd of Gad-flies, at this sudden
irruption which slaughtered them one after the other, drew back a
little all round, without quitting the treacherous shelter. It was so
hot outside! Why get excited?

Obviously, this suddenness of attack, followed by the swift removal of
the prey, does not allow the Bembex to regulate her dagger-play. The
sting no doubt performs its office, but it is directed without
precision at those spots which the hazards of the fight place within
its reach. I have seen Bembex, to finish off their half-killed
Gad-flies still struggling in the assassin’s grasp, munch the head and
thorax of the victims. This habit in itself proves that the Wasp wants
a genuine corpse and not a paralysed prey, since she ends the Fly’s
agony with so little ceremony. All things considered, therefore, I
think that, on the one hand, the nature of the prey, which dries up so
quickly, and, on the other hand, the difficulty of making such rapid
attacks, explain why the Bembex serve up dead prey to their larvæ and
consequently cater for them from day to day.

Let us watch the Wasp as she returns to the burrow with her capture
held under her abdomen between her legs. Here comes one, the Tarsal
Bembex (B. tarsata), who arrives laden with a Bee-fly. The nest is
situated at the sandy foot of a steep bank. The huntress announces her
approach by a shrill humming, which has something plaintive about it
and which continues until the insect sets foot to earth. We see the
Bembex hover above the bank and then dip straight down, very slowly and
cautiously, all the time emitting her shrill hum. Should her keen eye
descry anything unusual, she slackens her descent, hovers for a second
or two, goes up again, comes down again and flies away, swift as an
arrow. After a few moments, here she is once more. Hovering at a
certain height, she appears to be inspecting the locality, as if from
the top of an observatory. The vertical descent is resumed with the
most cautious slowness; finally, the Wasp alights with no hesitation
whatever at a spot which to my eye has naught to distinguish it from
the rest of the sandy surface. At that instant the plaintive whimper
ceases.

The insect, no doubt, has landed more or less on chance, since the most
practised eye cannot distinguish one spot from the other on that
expanse of sand; it has alighted somewhere near its home, of which it
will now seek the entrance, concealed after its last exit not only by
the natural falling-in of the materials but also by the Wasp’s own
careful sweeping. But no: the Bembex does not hesitate at all, does not
grope about, does not seek. By common consent the antennæ are looked
upon as organs for guiding insects in their searches. At this moment of
the return to the nest, I see nothing particular in the play of the
antennæ. Without once letting go her prey, the Bembex scratches a
little in front of her, at the very spot where she has alighted, gives
a push with her head and straightway enters, with the Fly under her
abdomen. The sand falls in, the door closes and the Wasp is at home.

It makes no difference that I have seen the Bembex return to her nest
hundreds of times; it is always with fresh astonishment that I behold
the keen-sighted insect find without hesitation a door whose presence
there is nothing to indicate. This door, in fact, is hidden with
jealous care, not now, after the Bembex has gone in—for the
obliterating sand does not become quite level of its own weight, but
leaves perhaps a slight depression, or an incompletely blocked
porch—but certainly after she comes out, for, when starting on an
expedition, she never fails to put a finishing touch to the result of
the natural landslip. Wait for her departure and you shall see her,
before flying off, sweep the front of the door and level it with
scrupulous care. When she is gone, I defy the most penetrating eye to
find the entrance. To discover it again, when the sandy expanse was of
any size, I had to resort to a kind of triangulation; and how often,
after a few hours’ absence, did not my combinations of triangles and my
efforts of memory prove to be at fault! All that remained was the
stake, a grass-stalk planted on the threshold; and even this method was
not always effective, for the insect, with its passion for continually
improving the outside of the nest, often made the bit of straw
disappear from sight.



CHAPTER XVI

A PARASITE OF THE BEMBEX. THE COCOON


I have shown the Bembex hovering with her cumbrous prize above the nest
and then dropping vertically and very slowly: a hesitating descent
accompanied by a sort of plaintive hum. This cautious arrival might
suggest that the insect is examining the ground from above in order to
find its door and trying to recall the locality before alighting. But
another motive is at work, as I propose to demonstrate. Under ordinary
conditions, when no sign of danger is apparent, the Wasp comes
suddenly, at full tilt, without any hovering, hesitating or whimpering,
and settles at once on her threshold or very near it. Her memory is so
faithful that she has no need to search about. Let us then look into
the cause of that hesitating approach which I described in the last
chapter.

The Wasp hovers, descends slowly, ascends again, flies away and
returns, because the nest is threatened by a very grave danger. Her
plaintive hum denotes anxiety: she never emits it when there is no
peril. But who is the enemy? Can it be I, sitting here and watching?
Why, no: I am nothing to her, nothing but a shapeless mass unworthy of
her attention. The formidable enemy, the fearsome foe that must be
avoided at all costs, is there, sitting motionless on the sand, near
the house. It is a miserable little Fly, feeble and inoffensive in
appearance. This insignificant Gnat is the terror of the Bembex. The
scourge of the Fly-tribe, the fierce slayer who so swiftly wrings the
necks of colossal Gad-flies sated with blood from an Ox’s back, does
not enter her own residence because she sees herself watched by another
Fly, a regular pigmy, who would make scarcely a mouthful for her larvæ.

Why does she not pounce upon her and get rid of the little wretch? The
Wasp is quick enough on the wing to catch her; and, small though the
capture be, the larvæ will not scorn it, since any sort of Fly suits
them. But no: the Bembex flees from a foe whom she could cut to bits
with a single stroke of her mandibles; it is to me as though I saw my
Cat fleeing in terror from a Mouse. The ardent huntress of Flies is
hunted by a Fly, and a small one at that. I bow before the facts
without hoping ever to understand this inversion of the parts played by
each insect. To be able to rid yourself easily of a mortal enemy who is
contemplating the ruin of your family and would furnish a nice little
meal for it, to be able to do that and not do it when the enemy is
there, within reach of you, watching you, defying you: this is the
height of animal aberration. But aberration is not the right word; let
us rather speak of the harmony of created things, for, since this
wretched little Fly has her tiny part to play in the general order, the
Bembex must needs respect her and like a craven flee before her, else
there would long since have been none of her left in the world.

Let us now tell the history of this parasite. Among the nests of the
Bembex, we find very frequently some that are occupied at the same time
by the larva of the Wasp and by other larvæ, strangers to the family
and gluttonous companions of the first. These strangers are smaller
than the Bembex’ nurseling, tear-shaped and of a purplish colour, due
to the tint of the baby-food that shows through the transparent body.
They vary in number: there are sometimes half-a-dozen of them,
sometimes ten or more. They belong to a species of Fly, as is evident
from their shape and also confirmed by the pupæ which we find in their
place. Home-breeding completes the proof. When reared in boxes, on a
layer of sand, with Flies renewed from day to day, they turn into pupæ
from which, a year later, there issues a small Fly, a Tachina of the
genus known as Miltogramma.

It is the same Fly that caused the Bembex such lively fears by lying in
ambush near the burrow. The Wasp’s terror is but too well founded. This
is what happens inside the dwelling: around the heap of food which the
mother exhausts herself in keeping up to the requisite quantity, seated
in company with the lawful offspring, are from six to ten hungry
guests, who dip their sharp-pointed mouths into the common dish with no
more restraint than if they were at home. Harmony seems to prevail at
the table. I have never seen the lawful larva grow indignant at the
indiscretion of the alien grubs, nor have I seen these appear to wish
to interfere with the other’s repast. All help themselves
indiscriminately and eat away peaceably without seeking a quarrel with
their neighbours.

So far all would be well, if a serious difficulty did not now arise.
However active the mother-nurse may be, she is obviously not equal to
such an output. She had to be constantly hunting to feed one larva, her
own; how could she possibly manage to provide for a dozen greedy
mouths? The result of this enormous increase of family can only be
want, or even starvation, not for the Fly’s maggots, which, developing
more quickly than the Bembex’ larva, get ahead of it and profit by the
days when there is still plenty for everybody, as their host is too
young to need much, but certainly for that unfortunate host, who
arrives at the transformation period without being able to make up for
lost time. Besides, even if the first visitors, in becoming pupæ, leave
him the free run of the table, others appear upon the scene, so long as
the mother continues to come to the nest, and complete his starvation.

In burrows invaded by numerous parasites, the Bembex’ larva is in point
of fact much smaller than one would suppose from the heap of food
consumed, the remains of which encumber the cell. Limp, emaciated,
reduced to a half or a third of its normal size, it vainly tries to
weave a cocoon for which it does not possess the silk; and it perishes
in a corner of the house among the pupæ of its more fortunate
companions. Its end may be more cruel still. Should the provisions
fail, should the mother-nurse delay too long in returning with food,
the Flies devour the larva of the Bembex. I verified this black deed by
rearing the brood myself. All went well so long as there was plenty to
eat; but, if the daily portion was omitted by accident or design, next
day or the day after I was sure to find the Fly’s grubs greedily
slicing up the larva of the Bembex. So, when the nest is invaded by the
parasites, the lawful larva is doomed to perish, either by hunger or by
a violent death; and this is what makes the Bembex hate the sight of
the Miltogrammæ prowling around her home.

The Bembex are not the only victims of these parasites: all the
Digger-wasps without distinction have their burrows plundered by
Tachinæ and especially Miltogrammæ. Different observers, notably
Lepeletier de Saint-Fargeau, have spoken of the wiles of these
bold-faced Flies; but none of them, so far as I know, has remarked this
very curious instance of parasitism at the expense of the Bembex. I say
very curious, because the conditions are quite different. The nests of
the other Digger-wasps are stocked beforehand and the Miltogramma drops
her eggs on the pieces of game as they are taken in. When the Wasp has
finished her catering and laid her egg, she closes the cell, where
henceforth the lawful larva and the alien larvæ hatch and live together
without ever being visited in their solitude. The mother therefore is
not aware of the parasites’ brigandage, which remains unpunished
because it is unknown.

With the Bembex it is quite another matter. The mother is constantly
returning indoors during the fortnight which it takes to rear her
grubs; she knows that her offspring is living in the company of a
number of intruders, who appropriate the best part of the food; each
time that she brings provisions to her larva, she touches and feels at
the bottom of the cavity those hungry guests who, far from contenting
themselves with the remnants, seize upon the pick of the victuals; she
must perceive, however limited her arithmetical faculties, that twelve
are more than one; besides, the consumption of food, which is out of
all proportion to her hunting powers, would tell her; and yet, instead
of taking those presumptuous aliens by the skin of the belly and
chucking them out of doors, she placidly tolerates them.

Tolerates them, did I say? Why, she feeds them, she brings them
provisions, having perhaps for those intruders the same affection as
for her own larva! It is a new version of the story of the Cuckoo, but
with even more singular circumstances. The theory that the Cuckoo,
almost the size of the Sparrow-hawk and wearing the same dress,
inspires enough respect to enable her to introduce her egg with
impunity into the feeble Warbler’s nest, and that the latter, in her
turn, perhaps over-awed by the fearsome appearance of her Toad-faced
nurseling, accepts and looks after the stranger: this theory has some
plausibility. But what should we say if the Warbler turned parasite
and, with superb audacity, went and confided her eggs to the eyrie of
the bird of prey, to the nest of the Sparrow-hawk himself, the
bloodthirsty devourer of Warblers? What should we say if the rapacious
Hawk accepted the trust and fondly reared the brood of little birds?
And this is exactly what the Bembex does, that ravisher of Flies who
tenderly nurses other Flies, that huntress who provides food for a
quarry whose last meal will be made on her own disembowelled larva! I
leave it to others, cleverer than myself, to interpret these
astonishing relations.

Let us observe the tactics employed by the Tachina for the purpose of
confiding her eggs to the Digger’s nest. It is an absolute rule that
the Gnat never enters the burrow, even though she should find it open
and the owner absent. The sly parasite would think twice about
venturing down a passage where, being no longer free to escape, she
might pay dear for her brazen effrontery. For her the one and only
favourable moment for her designs, a moment awaited with exquisite
patience, is that at which the Wasp dives into the gallery, with her
prey clasped to her belly. At that instant, however short it may be,
when the Bembex or any other Digger has half her body well within the
entrance and is about to disappear underground, the Miltogramma dashes
up and settles on the piece of game that projects a little way beyond
the hinder extremity of the ravisher; and, while the Bembex is delayed
by the difficulty of entering, the other, with unparalleled swiftness,
lays an egg on the prey, or even two or three in quick succession.

The hesitation of the Wasp hampered by her load lasts but the twinkling
of an eye. No matter: this is long enough for the Gnat to accomplish
her misdeed without allowing herself to be carried beyond the
threshold. How smoothly her organs must work to adapt themselves to
this instantaneous laying! The Bembex disappears, herself introducing
the enemy to the home; and the Tachina goes and squats in the sun,
close to the burrow, to meditate fresh deeds of darkness. If we wish to
make sure that the Fly’s eggs have really been laid during this rapid
manœuvre, we need only open the burrow and follow the Bembex to the
bottom of her dwelling. The prey which we take from her bears at the
tip of its abdomen at least one egg, sometimes more, according to the
length of the delay at the entrance. These eggs are too small to belong
to any but a parasite; besides, if any doubt remained, separate rearing
in a box results in Fly-grubs, followed by the pupæ and lastly the
Miltogrammæ themselves.

The moment adopted by the Gnat is chosen with great discrimination: it
is the only moment when she is able to accomplish her designs without
danger, and without useless dodging about. The Wasp, half-trapped in
the entrance-hall, cannot see the foe so daringly perched on the
hind-quarters of the prey; if she suspects the parasite’s presence, she
cannot drive her away, having no liberty of movement in the narrow
corridor; lastly, in spite of all the precautions which she takes to
facilitate her entrance, she cannot always vanish underground with the
necessary speed, the fact being that the bandit is much too quick for
her. This indeed is the auspicious moment and the only one, since
prudence forbids the Fly to penetrate into the cave where other Flies,
far stronger than herself, serve as food for the grub. Outside, in the
open air, the difficulty is insurmountable, thanks to the intense
vigilance of the Bembex. Let us turn for a minute to the arrival of the
mother while her home is being watched by Miltogrammæ.

A number of these Midges, greater or less from time to time but usually
three or four, station themselves on the sand and remain perfectly
still, all gazing at the burrow, of which they well know the entrance,
carefully hidden though it be. Their dull-brown colour, their great
blood-red eyes, their indefatigable patience have often suggested to me
a picture of brigands, clad in dark frieze, with a red handkerchief
round their heads, waiting in ambush for the moment to strike a felon
blow. The Wasp arrives carrying her prey. If nothing of an alarming
nature troubled her, she would then and there alight at her door. But
she hovers at a certain height, comes down slowly and circumspectly,
hesitates; and a plaintive whimpering, resulting from a special
vibration of her wings, expresses her fears. She has seen the
malefactors therefore. They too have seen the Bembex: they follow her
with their eyes, as the movement of their red heads shows; every gaze
is turned towards the coveted booty. Now come the marches and
countermarches of craft striving to outwit prudence.

The Bembex comes straight down, with an imperceptible flight, as though
letting herself drop inertly, buoyed up by the parachute of her wings.
She is now hovering a hand’s breadth above the ground. This is the
moment. The Midges take flight and all make for the rear of the Wasp;
they hover in her wake, some nearer, some farther, in a geometrical
line. If the Bembex turns to thwart their designs, they also turn, with
a precision that keeps them in the rear on the same straight line; if
she advances, they advance; if she retreats, they retreat, letting the
Wasp set their pace all the time, now flying slowly, now coming to a
standstill, according to the behaviour of their leader, the Bembex.
They make no attempt to fling themselves on the object of their
cupidity; their tactics are confined to keeping ready, in this
rearguard position, which will save them any hesitation at the critical
moment.

Sometimes, wearying of this obstinate pursuit, the Bembex alights; the
others instantly settle on the sand, still in the rear, and do not
budge. The Wasp darts off again, with a shriller whimpering, a sign no
doubt of increasing indignation; the Midges dart after her. One last
method remains of throwing off the persistent Flies: dashing off at
full speed, the Bembex flies far away, hoping perhaps to mislead the
parasites by rapid evolutions across country. But the wary Gnats are
not caught in the trap: they let her go and once more take up their
positions on the sand around the burrow. When the Bembex returns, the
same pursuit will begin all over again, until at last the parasites’
obstinacy has worn down the mother’s prudence. In that second when her
vigilance is relaxed, the Flies are straightway there. One of them,
occupying the most favourable spot, swoops upon the disappearing prey
and the deed is done: the egg is laid.

There is ample evidence that the Bembex is aware of the danger. The
Wasp knows how disastrous the presence of the hateful Gnat may be to
the future of the nest; on this point her prolonged attempts to put off
the Tachinæ, her hesitations, her flights leave not the shadow of a
doubt. Then how is it, I ask myself once more, that the Fly-huntress
allows herself to be worried by another of the tribe, by an
infinitesimal bandit, incapable of the least resistance, whom she could
reach with a sudden rush if she tried? Why not relieve herself of the
prey that clogs her movements and swoop down upon those evil-doers?
What would be needed to exterminate the ill-omened brood that hangs
around the burrow? A battue that would take her a few seconds. But the
harmony of the universe, the laws that regulate the preservation of
species, will not have it so; and the Bembex will always allow
themselves to be harassed without ever learning from the famous
‘struggle for life’ the radical method of extermination. I have seen
them sometimes, when too close-pressed by the Midges, drop their prey
and fly away in mad haste, but without any hostile demonstration,
though the putting down of the burden left them quite free in their
movements. The abandoned prey, but now so ardently coveted by the
Tachinæ, lay on the ground, for all to do as they pleased with; and not
one of them took any notice of it. This game lying in the open air had
no value for the Midges, whose larvæ require the shelter of a burrow.
It was valueless also to the suspicious Bembex, who, on returning, felt
it for a moment and left it with scorn. A momentary break in her
vigilance had made her doubtful of it.



We will end this chapter with the story of the larva. Its monotonous
life offers nothing remarkable in the fortnight during which it eats
and grows. Next comes the construction of the cocoon. The meagre
development of the silk-producing organs does not allow the grub a
dwelling of pure silk, composed, like those of the Ammophilæ and the
Sphex, of several wrappers, one outside the other, which protect the
larva and afterwards the nymph against the inroads of damp in a shallow
and exposed burrow when the rains of autumn come and the snows of
winter. Nevertheless, the Bembex’ burrow is in a worse plight than that
of the Sphex, being situated at a depth of a few inches in easily
saturated soil. Therefore, in order to construct itself an adequate
shelter, the larva makes up by its industry for its small quantity of
silk. With grains of sand artistically put together and cemented with
the silky material it builds itself an exceedingly solid cocoon,
impenetrable to damp.

Three general methods are employed by the Digger-wasps in constructing
the sanctum in which the metamorphosis is to take place. Some dig their
burrows at great depths, under shelter: their cocoon then consists of a
single envelope, so thin as to be transparent. This is the case with
the Philanthi and the Cerceres. Others are content with a shallow
burrow in open ground; but in that case they sometimes have enough silk
to increase the number of wrappers for the cocoon, as we see with the
Sphex, the Ammophilæ and the Scoliæ, or sometimes the quantity of silk
is insufficient, when they have recourse to gummed sand, this being the
method practised by the Bembex, the Stizi and the Palari. A
Bembex-cocoon is so compact and strong that it might be taken for the
kernel of some seed. The form is cylindrical, with one end rounded and
the other pointed. The length is about three-quarters of an inch. On
the outside it is slightly wrinkled and rather coarse to look at; but
the inner walls are glazed with a fine varnish.

My experiments in indoor breeding have enabled me to observe every
detail of the construction of this architectural curiosity, a regular
strong-box inside which the inclemencies of the weather can be braved
in safety. The larva first pushes away the remains of its food and
forces them into a corner of the cell or compartment which I have
arranged for it in a box with paper partitions. Having swept the floor,
it fixes at the different walls of its dwelling threads of a beautiful
white silk, forming a spidery web which keeps off the cumbrous heap of
broken victuals and serves as a scaffolding for the next work.

This work consists of a hammock slung far from any dirt, in the centre
of the threads stretched from wall to wall. Nothing but silk,
magnificently fine, white silk, enters into its composition. Its shape
is that of a sack open at one end with a wide circular mouth, closed at
the other and ending in a point. An eel-trap would give a very fair
picture of it. The edges of the mouth are kept apart and permanently
stretched by numerous threads starting from there and fastened to the
adjoining walls. Lastly, the texture of this sack is extremely fine and
allows us to see all the grub’s proceedings.

Things had been in this condition since the day before, when I heard
the larva scratching in the box. I opened it and found my prisoner
engaged in scraping the cardboard wall with its mandibles, while its
body was half outside the sack. The cardboard had already suffered
considerably and a heap of tiny fragments were piled in front of the
opening of the hammock, to be used later. For lack of other materials,
the grub would doubtless have employed these scrapings for its
building. I thought it better to provide something in accordance with
its tastes and to give it sand. Never had Bembex-larva built with such
sumptuous materials. I poured before the captive sand from my
ink-stand: blotting-sand, blue sand sprinkled with little gilt mica
spangles.

This supply is placed in front of the mouth of the bag. The bag itself
is in a horizontal position, which is convenient for the coming task.
The larva, leaning half out of the hammock, picks up its sand almost
grain by grain, rummaging in the heap with its mandibles. If any grain
is found to be too bulky, the grub takes it and throws it away. When
the sand is thus sorted, the larva introduces a certain quantity into
the silken edifice by sweeping it with its mouth. This done, it retires
into the eel-trap and begins to spread the materials in a uniform layer
on the lower surface of the sack; then it gums the different grains and
inlays them in the fabric, using silk as cement. The upper surface is
built more slowly: the grains are carried up one by one and fixed on
with the silken putty.

This first layer of sand as yet embraces only the front half of the
cocoon, the half that ends at the mouth of the bag. Before turning
round to work at the back half, the grub renews its supply of materials
and takes certain precautions so as not to be hindered in its mason’s
work. The sand outside, heaped up in front of the entrance, might slip
inside and embarrass the builder in so narrow a space. The grub
foresees this possibility: it glues a few grains together and makes a
rough curtain of sand, which stops up the orifice very imperfectly, but
sufficiently to prevent an accident. Having taken these precautions,
the larva works at the back half of the cocoon. From time to time it
turns round to fetch fresh supplies from outside, tearing a corner of
the curtain that protects it against the outer sand and grabbing
through this window the materials which it requires.

The cocoon is still incomplete, wide open at the big end; it wants the
spherical cap that is to close it. For this final labour the grub takes
a plentiful supply of sand, the last supply of all, and then pushes
away the heap outside the entrance. At the opening it now weaves a
silken cap, which fits the mouth of the primitive eel-trap precisely.
Lastly, grains of sand, kept in reserve inside, are laid one by one
upon this silken foundation and glued together with silky slime. Having
finished this lid, the larva has nothing else to do but give the last
finish to the inside of the abode and glaze the walls with varnish to
protect its delicate skin against the rough sand.

The hammock of pure silk and the hemisphere that closes it later are,
as we see, but a scaffolding intended to support the masonry of sand
and give it a regular curve; they might be compared with the wooden
moulds which builders set up when constructing an arch, a vault. Once
the work is done, the timber frame is taken away and the vault is
sustained by virtue of its perfect balance. Even so, when the cocoon is
finished, the silken support disappears, partly lost in the masonry,
partly destroyed by contact with the coarse earth; and not a trace
remains of the ingenious method followed in welding together materials
with so little consistency as sand into a building of such perfect
regularity.

The round cap closing the mouth of the original eel-trap is a work
apart, adjusted to the main body of the cocoon. However well the two
parts are fitted and soldered, the solidity is not the same as the
larva would obtain if it built its whole dwelling continuously. The
circumference of the lid therefore has a circular line of least
resistance. But this is not a fault of construction; on the contrary,
it is a fresh improvement. The insect would find grave difficulty in
issuing later from its strong-box, so stout are the walls. The line of
junction, weaker than the others, would seem to save it a good deal of
effort, for it is mostly along this line that the cover is removed when
the Bembex emerges from the ground in the perfect state.

I have called this cocoon a strong-box. It is indeed a very solid piece
of work, both from its shape and from the nature of its materials.
Landslips or subsidences cannot alter its outline, for the strongest
pressure of one’s fingers does not always succeed in crushing it.
Therefore it matters little to the larva if the ceiling of its burrow,
dug in loose soil, should fall in sooner or later; it does not care
much if a passing foot should press upon it under its thin covering of
sand; it has nothing to fear once it is enclosed in its stout bulwark.
Nor does damp endanger it. I have kept Bembex-cocoons immersed in water
for a fortnight at a time without afterwards discovering the least
trace of dampness inside them. Why have we no such waterproofing for
our dwellings!

Lastly, thanks to its graceful oval, this cocoon seems rather the
product of some elaborate manufacture than that of a grub. To any one
unacquainted with the secret, the cocoons which I had built with
blotting-sand might have been jewels of some unknown workmanship, great
beads studded with golden spots on a lapis-lazuli ground, destined to
form the necklace of a Polynesian belle.



CHAPTER XVII

THE RETURN TO THE NEST


The Ammophila sinking her well at a late hour of the day leaves her
work, after closing the orifice with a stone lid, flits away from
flower to flower, goes to another part of the country, and yet next day
is able to come back with her caterpillar to the home excavated on the
day before, notwithstanding the unfamiliar locality, which is often
quite new to her. The Bembex, laden with game, alights with almost
mathematical precision on the threshold of her door, which is blocked
with sand and indistinguishable from the rest of the sandy expanse.
Where my sight and recollection are at fault, their eyes and their
memory possess a sureness that is very nearly infallible. One would
think that insects had something more subtle than mere remembrance, a
kind of intuition for places to which we have nothing similar, in
short, an indefinable faculty which I call memory, failing any other
expression to denote it. There can be no name for the unknown. In order
to throw if possible a little light on this detail of animal
psychology, I made a series of experiments which I will now describe.
[40]

The first has for its subject the Great Cerceris, who hunts
Cleonus-weevils. About ten o’clock in the morning I catch twelve
females, all belonging to the same colony and at work on the same bank,
busy digging burrows or victualling them. Each prisoner is placed
separately in a little paper bag and the whole lot put in a box. I walk
about a mile and a half from the site of the nests and then release my
Cerceres, first taking care, so that I may know them later, to mark
them with a white dot in the middle of the thorax, using a straw dipped
in indelible paint.

The Wasps fly only a few yards away, in every direction, one here,
another there; they settle on blades of grass, pass their fore-tarsi
over their eyes for a moment, as though dazzled by the bright sunshine
to which they have suddenly been restored; then they take flight, some
sooner, some later, and all, without hesitation, make straight for the
south, that is to say, for home. Five hours later I return to the
common site of the nests. I am hardly there when I see two of my
Cerceres with white dots working at the burrows; soon a third arrives
from the fields, with a Weevil between her legs; a fourth is not slow
in following. The recognition of four out of twelve in less than
fifteen minutes was enough to convince me. I thought it unnecessary to
wait any longer. What four could do the others would do, if they had
not already done it; and I was quite at liberty to presume that the
absent eight were out hunting or else hidden in their underground
galleries. Therefore, carried for a mile and a half in a direction and
by a road of which they could not have taken cognizance in their paper
prisons, the Cerceres, or at least some of them, had returned home.

I do not know how far the Cerceres’ hunting-grounds extend; and it is
possible that they know the country more or less over a radius of a
mile and a half. In that case, they would not have felt sufficiently
lost at the spot to which I moved them and they would have got home by
their acquired local knowledge. The experiment had to be repeated, at a
greater distance and from a starting-point which the Wasp could not be
suspected of knowing.

I therefore take nine female Cerceres from the same group of burrows
that supplied me in the morning. Three of them had just been subjected
to the previous test. They were again carried in a dark box, each
insect enclosed in its paper bag. The starting-point selected is the
nearest town, Carpentras, which lies at about two miles from the
burrow. I am to release my insects not among the fields, as on the
first occasion, but absolutely in the street, in the centre of a
crowded neighbourhood, where the Cerceres, with their rustic habits,
had certainly never penetrated. As the day is already far advanced, I
postpone the experiments; and my captives spend the night in their
prison-cells.

Next morning, at about eight, I mark them on the thorax with two white
spots, to distinguish them from yesterday’s lot, who were marked with
only one; and I set them free, one after the other, in the middle of
the street. Each Cerceris released first shoots straight up between the
two rows of houses, as though to escape as soon as possible from the
narrow street and gain the spacious horizons; then, rising above the
roofs, she at once darts away vigorously towards the south. And it was
from the south that I brought them; it is in the south that their
burrows are. Nine times, with nine prisoners, freed one after the
other, I had this striking instance of the way in which the insect
stranded far from home takes without hesitation the right direction for
returning to the nest.

I myself was at the burrows a few hours later. I saw several of
yesterday’s Cerceres, recognizing them by the one white spot on the
thorax; but I saw none of those whom I had just let loose. Had they not
been able to find their home again? Were they hunting? Or were they
hiding in their galleries to recover from the excitement of such a
trial? I do not know. Next day I paid a fresh visit; and this time I
had the satisfaction of finding at work, as active as though nothing
out of the way had happened, five of the Cerceres with two white spots
on the thorax. A journey of quite two miles, the town with its houses,
its roofs, its smoky chimneys, all things so new to these utter
rustics, had not prevented them from going back to the nest.

When taken from his brood and carried to enormous distances, the Pigeon
returns promptly to the dovecote. If we wanted to work out a proportion
between the length of the journey and the size of the creature, how
greatly superior to the Pigeon would be the Cerceris, who finds her
burrow after being carried a distance of two miles! The bulk of the
insect is not a cubic centimetre, [41] whereas that of the Pigeon must
be quite a cubic decimetre, [42] if not more. The bird, being a
thousand times larger than the Wasp, ought therefore, in order to rival
her, to find the dovecote at a distance of two thousand miles, which is
thrice the greatest length of France from north to south. I do not know
that a Carrier-pigeon has ever performed such a feat. But power of
flight and, still less, lucidity of instinct are qualities that cannot
be measured by the yard. Comparative size cannot here be taken into
consideration; and we must just look upon the insect as a worthy rival
of the bird, without deciding which of the two has the advantage.

In returning to the dovecote and the burrow, when man has artificially
made them lose their bearings and carried them to great distances, in
unfamiliar directions and into regions which they have not yet visited,
are the Pigeon and the Cerceris guided by recollection? Is memory their
compass when, on reaching a certain height, whence they can, so to
speak, pick up the scent after a fashion, they dart with all their
power of wing towards the horizon where their nests are? Is it memory
that traces their road through the air, across regions which they are
seeing for the first time? Obviously not: there can be no recollection
of the unknown. The Wasp and the bird are unacquainted with the country
around; nothing can have told them the general direction in which they
were moved, for the journey was made in the darkness of a closed basket
or a box. Locality, relative position: everything is unknown to them;
and yet they find their way. They therefore have something better than
mere memory as a guide: they have a special faculty, a sort of
topographical sense of which we cannot possibly form an idea, having
nothing similar ourselves.

I will show by experiment how subtle and precise this faculty is within
its narrow province, and also how obtuse and dull it becomes when
driven to depart from the usual conditions in which it acts. This is
the invariable antithesis of instinct.

A Bembex, actively engaged in feeding her larva, leaves the burrow. She
will return presently with the produce of the chase. The entrance is
carefully stopped up with sand, which the insect has swept there
backwards before going away; there is nothing to distinguish it from
other points of the sandy surface; but this does not trouble the Wasp,
who finds her door with a skill which I have already emphasized. Let us
devise some insidious plot and change the conditions of the locality in
order to perplex the insect. I cover the entrance with a flat stone,
the size of my hand. The Wasp soon arrives. The great change effected
on her threshold during her absence appears to cause her not the
slightest hesitation; at least, the Bembex at once alights upon the
stone and tries, for an instant, to dig into it, not at random but at a
spot corresponding with the opening of the burrow. The hardness of the
obstacle soon dissuades her from her enterprise. She then runs about
the stone in every direction, goes all round it, slips underneath and
begins to dig in the exact direction of her dwelling.

The flat stone is not enough to mislead our wide-awake friend; we must
find something better. To cut things short, I do not allow the Bembex
to continue her excavations, which, I can see, will soon prove
successful; I drive her off with my handkerchief. The fairly long
absence of the frightened insect will give me time to prepare my snares
at leisure. What materials shall I employ now? In these improvised
experiments we must know how to turn everything to use. Not far off, on
the high-road, are the fresh droppings of some beast of burden. The
very thing! The droppings are collected, broken up, crumbled and then
spread in a layer at least an inch thick on the threshold of the burrow
and all around, covering about a quarter of a square yard. This
certainly is a house-front the like of which no Bembex ever knew. The
colouring, the nature of the materials, the stercoral effluvia all
combine to mystify the Wasp. Will she take all this—that expanse of
manure, that dung—for the front of her door? Why, yes: here she comes!
She inspects the unwonted condition of the place from above and settles
in the middle of the layer, just opposite the entrance. She digs, makes
a hole through the stringy mass and reaches the sand, where she at once
finds the orifice of the passage. I stop her and drive her away a
second time.

Is not the precision with which the Wasp alights just in front of her
door, though this be masked in a way so new to her, a proof that sight
and memory are not her only guide? What else can there be? Could it be
scent? It is very doubtful, for the emanations from the droppings have
not been able to baffle the insect’s perspicacity. Still, let us try a
different smell. I happen to have on me, as part of my entomological
luggage, a small phial of ether. I sweep away the sheet of manure and
replace it by a blanket of moss, not very thick, but spreading to a
considerable distance; and I pour the contents of my phial on it as
soon as I see the Bembex arrive. The ethereal fumes, at first too
strong, keep the Wasp away, but only for a moment. Then she alights on
the moss, which still exhales a very perceptible smell of ether, passes
through the obstacle and makes her way indoors. The ethereal effluvia
put her out no more than did the stercoral effluvia. Something surer
than scent tells her where her nest lies.

The antennæ have often been suggested as the seat of a special sense
able to guide insects. I have already shown how the amputation of those
organs seems in no way to impede the Wasp’s investigations. Let us try
once more, under more complicated conditions. I seize the Bembex, cut
off her antennæ at the roots, and at once release her. Goaded by pain,
maddened at having been imprisoned in my fingers, the insect darts off
faster than an arrow. I have to wait for a good hour, very uncertain as
to whether it will come back. The Wasp arrives however and, with her
unvarying precision, alights quite close to her door, whose appearance
I have changed for the fourth time. The site of the nest is now covered
with a spreading mosaic of pebbles the size of a walnut. My work,
which, as regards the Bembex, surpasses what the megalithic monuments
of Brittany or the rows of menhirs at Carnac are to us, is powerless to
deceive the mutilated insect. Though deprived of her antennæ, the Wasp
finds her entrance in the middle of my mosaic as easily as the same
insect, supplied with those organs, would have done under other
conditions. This time I let the faithful mother go indoors in peace.

Four successive alterations in the site; changes in the colour, the
smell, the materials of the outside of the home; lastly, the pain of a
double wound: all had failed to baffle the Wasp or even to make her
waver as to the precise locality of her door. I had come to the end of
my stratagems and understood less than ever how the insect, if it
possess no special guide in some faculty unknown to us, can find its
way when sight and scent are baffled by the artifices which I have
mentioned.

A few days later, a lucky experiment reopened the question and allowed
me to study it under another aspect. In this case we uncover the
Bembex’ burrow all the way along, without changing its appearance too
much, an operation made easier by the shallowness of the burrow, its
almost horizontal direction, and the lack of consistency of the soil in
which it is dug. With this object we scrape the sand away gradually
with a knife. Thus deprived of its roof from end to end, the
underground dwelling becomes an open trench, a conduit, straight or
curved, some eight inches long, open at the spot where the
entrance-door used to be and finishing in a blind alley at the other
end, where the larva lies amid its victuals.

Here is the home uncovered, in the bright light, under the sun’s rays.
How will the mother behave on her return? Let us consider the question
in detail, according to scientific precepts: it is a perplexing
position for the observer, as my recent experiences make me suspect.
Here is the problem: the mother on arriving has the feeding of her
larva as her object in view; but to reach this larva she must first
find the door. The grub and the entrance-door: those are the two
aspects of the question that appear to me to merit separate
consideration. I therefore take away the grub, together with the
provisions, and the end of the passage becomes a clear space. After
making these preparations there is nothing to do but exercise patience.

The Wasp arrives at last and goes straight to where its door ought to
be, that door of which naught but the threshold remains. Here, for more
than an hour, I see her digging on the surface, sweeping, making the
sand fly, and persisting, not in scooping out a new gallery, but in
looking for that loose door which ought easily to give way before a
mere push of the head and let the insect through. Instead of yielding
materials, she finds firm soil, not yet disturbed. Warned by this
resistance, she confines herself to exploring the surface, always in
close proximity to the spot where the entrance should be. A few inches
on either side is all that she allows herself. The places which she has
already tested and swept twenty times over she returns to test and
sweep again, unable to bring herself to leave her narrow radius, so
obstinate is her conviction that the door must be here and not
elsewhere. Several times in succession I push her gently with a straw
to some other point. She will not be put off: she returns straightway
to the place where her door once stood. At rare intervals the gallery,
now an open trench, seems to attract her attention, though very
faintly. The Bembex takes a few steps towards it, still raking, and
then goes back to the entrance. Twice or thrice I see her run the whole
length of the conduit and reach the blind alley, the abode of her grub;
here she gives a few careless strokes of the rake and hurries back to
the spot where the entrance used to be, continuing her quest there with
a persistency that ends by wearying mine. More than an hour has passed
and the stubborn Wasp is still pursuing her search on the site of the
vanished doorway.

What will happen when the larva is present? This is the next aspect of
the question. To continue the experiment with the same Bembex would not
have given me the positive evidence which I wanted, for the insect,
rendered more obstinate by its vain quest, seemed to me now obsessed by
a fixed idea, which would certainly have obscured the facts which I
wished to ascertain. I needed a fresh subject, one not over-excited and
solely concerned with the impulses of the first moment. An opportunity
soon presented itself.

I uncover the burrow from end to end as I have just explained, but
without touching the contents: I leave the larva in its place, I
respect the provisions; everything in the house is in order; there is
nothing lacking but the roof. Well, in front of this open dwelling, of
which the eye freely takes in every detail: entrance-hall, gallery,
cell at the back with the grub and its heap of Flies; in front of this
dwelling now a trench, at the end of which the larva wriggles under the
blistering rays of the sun, the mother behaves exactly as her
predecessor did. She alights at the point where the entrance used to
be. It is here that she does her digging and sweeping; and it is here
that she always returns after hurried visits elsewhere, within a radius
of a few inches. There is no exploration of the tunnel, no anxiety
about the tortured larva. The grub, whose delicate epidermis has just
passed from the cool moisture of an underground cave to the fierce
blaze of an untempered sun, is writhing on its heap of chewed Flies;
the mother does not give it a thought. To her it is no more than any
other object lying on the sand: a little pebble, a pellet of earth, a
scrap of dry mud, nothing more. It is unworthy of attention. This
tender and faithful mother, who wears herself out in trying to reach
her nurseling’s cradle, is wanting at the moment her entrance-door, the
usual door and nothing but that door. What stirs her maternal heart is
her yearning for the well-known passage. And yet the way is open: there
is nothing to stop the mother; and the grub, the ultimate object of her
anxiety, is tossing restlessly before her eyes. One bound would bring
her to the side of the poor thing clamouring for assistance. Why does
she not rush to her beloved nurseling? She could dig it a new dwelling
and swiftly place it in safety underground. But no; the mother persists
in seeking a passage that no longer exists, while her child is grilling
in the sun before her eyes. My surprise is intense in the presence of
this short-sighted mother, though the sense of motherhood is the most
powerful and resourceful of all the feelings that stir the animal
creation. I should hardly believe the evidence of my eyes but for
experiments endlessly repeated with Cerceres and Philanthi as well as
with Bembex of different species.

Here is something more remarkable still: the mother, after prolonged
hesitation, at last enters the roofless trench, all that remains of the
original corridor. She goes forward, draws back, goes forward again,
giving a few careless sweeps, here and there, without stopping. Guided
by vague recollections and perhaps also by the smell of game emitted by
the heap of Flies, she occasionally reaches the end of the gallery, the
very spot at which the larva lies. Mother and son are now together. At
this moment of meeting after long suffering, have we a display of eager
solicitude, exuberant affection, any signs whatever of maternal joy? If
you think so, you need only repeat my experiments to persuade yourself
to the contrary. The Bembex does not recognize her larva at all; it is
to her a worthless thing, something in her way, a nuisance. She walks
over the grub, treads on it ruthlessly, as she hurries to and fro. When
she wants to try and dig at the bottom of the cell, she thrusts it back
with a brutal kick; she shoves it on one side, topples it over, flings
it out as unceremoniously as if it were a big bit of gravel that
hindered her in her work. Thus knocked about, the grub thinks of
defending itself. I have seen it seize its mother by the tarsus with no
more ceremony than it shows when it bites off the leg of its prey, the
Fly. The struggle was hotly contested; but at last the fierce mandibles
let go and the mother vanished in terror, making a shrill whimpering
noise with her wings. This unnatural sight of the son biting his mother
and perhaps even trying to eat her is uncommon and is brought about by
circumstances which the observer has not at his command; but what can
always be witnessed is the Wasp’s profound indifference towards her
offspring and the brutal contempt with which she treats that irksome
lump of rubbish, the grub. Once she has raked out the end of the
passage, which is the work of a moment, the Bembex returns to her
favourite spot, the threshold, where she resumes her useless search. As
for the grub, it continues to writhe and wriggle wherever its mother
has kicked it. It will die without the mother’s coming to its
assistance, for she fails to recognize it because she was unable to
find the customary passage. Go back to-morrow and you shall see it
lying in its trench, half baked by the sun and already a prey to the
very Flies that were once its prey.

Such is the concatenation of instinctive actions, linked one to the
other in an order which the gravest circumstances are powerless to
disturb. What, after all, is the Bembex looking for? Her larva,
obviously. But, to get at that larva, she must enter the burrow; and,
to enter that burrow, she must first of all find the door. And it is in
the search for this door that the mother persists, despite the
wide-open gallery, despite the provisions, despite the grub, all
exposed to view. At the moment she cares not that her house is in ruins
and her family in danger; what she wants above all things is the
familiar passage, the passage through the loose sand. Perish
everything, dwelling and inmate, if this passage be not found! Her
actions are like a series of echoes each awakening the next in a
settled order, which allows none to sound until the previous one has
sounded. The first action could not be performed, not because of an
obstacle, for the house is wide open, but for want of the usual
entrance. That is enough: the subsequent actions shall not be
performed; the first echo was dumb and all the rest are silent. What a
gulf separates intelligence and instinct! Through the ruins of the
demolished dwelling, a mother guided by intelligence hurries straight
to her son; guided by instinct, she comes to a stubborn halt on the
site of her old door.



CHAPTER XVIII

THE HAIRY AMMOPHILA


One day in May I was walking up and down, on the look-out for anything
fresh that might be taking place in the harmas [43] laboratory. Favier
was not far off, at work in the kitchen-garden. Who is Favier? I may as
well say a few words about him at once, for we shall be hearing of him
again.

Favier is an old soldier. He has pitched his hut of clay and branches
under the African carob-trees; he has eaten Sea-urchins at
Constantinople; he has shot Starlings in the Crimea, during a lull in
the firing. He has seen much and remembered much. In winter, when work
in the fields ends at four o’clock and the evenings are long, he puts
away rake, fork, and barrow and comes and sits on the hearth-stone of
the kitchen fireplace, where the billets of ilex-wood blaze merrily. He
fetches out his pipe, fills it methodically with a moistened thumb and
smokes it solemnly. He has been thinking of it for many a long hour;
but he has abstained, for tobacco is expensive. The privation has
doubled the charm; and not a puff, recurring at regular intervals, is
wasted.

Meanwhile, we start talking. Favier is, in his fashion, one of those
bards of old who were given the best seat at the hearth, for the sake
of their tales; only, my story-teller was formed in the barrack-room.
No matter: the whole household, large and small, listen to him with
interest; though his speech is full of vivid images, it is always
decent. It would be a great disappointment to us if he did not come,
when his work was done, to take his ease in the chimney-corner.

What does he talk about to make him so popular? He tells us what he saw
of the coup d’État to which we owe the hated Empire; he talks of the
brandy served out and of the firing into the mob. He—so he assures
me—always aimed at the wall; and I accept his word for it, so
distressed does he appear to me and so ashamed of having taken a hand,
however innocent, in that felon’s game.

He tells us of his watches in the trenches before Sebastopol; he speaks
of his sudden terror when, at night, all alone on outpost duty,
squatting in the snow, he saw fall beside him what he calls a
flower-pot. It blazed and flared and shone and lit up everything
around. The infernal machine threatened to burst at every second; and
our man gave himself up for lost. But nothing happened: the flower-pot
went out quietly. It was a star-shell, an illuminating contrivance
fired to reconnoitre the assailant’s outworks in the dark.

The tragedy of the battle-field is followed by the comedy of the
barracks. He lets us into the mysteries of the stew-pan, the secrets of
the mess, the humorous hardships of the cells. And, as his stock of
anecdotes, seasoned with racy expressions, is inexhaustible, the
supper-hour arrives before any of us has had time to remark how long
the evening is.

Favier first attracted my notice by a master-stroke. One of my friends
had sent me from Marseilles a pair of enormous Crabs, the Maia, the
Sea-spider or Spider-crab of the fishermen. I was unpacking the
captives when the workmen returned from their dinner: painters,
stone-masons, plasterers engaged in repairing the house which had been
empty so long. At the sight of those strange animals, studded with
spikes all over the carapace and perched on long legs that give them a
certain resemblance to a monstrous Spider, the onlookers gave a cry of
surprise, almost of alarm. Favier, for his part, remained unmoved; and,
as he skilfully seized the terrible Spider struggling to get away, he
said

‘I know that thing; I’ve eaten it at Vasna. It’s first-rate.’

And he looked round at the bystanders with an air of humorous mockery
which was meant to convey:

‘You’ve never been out of your hole, you people.’

One more story of him, to have done. A woman living in his
neighbourhood had been, by the doctor’s advice, to take the sea-baths
at Cette. She returned from her trip bringing with her a curious thing,
a strange fruit on which she based high hopes. When held to the ear and
shaken, it rattled, proving that it contained seeds. It was round and
prickly. At one end was a sort of bud, closed with a little white
flower; at the other, a slight cavity was pierced with a few holes.

The neighbour ran round to Favier to show him her find and asked him to
mention it to me. She would make me a present of the precious seeds,
the idea being that some wonderful shrub would grow from them and
beautify my garden.

‘Vaqui la flou, vaqui lou pécou: here is the flower, here is the tail.’
she said, showing Favier the two ends of her fruit.

Favier roared with laughter:

‘It’s a Sea-urchin.’ he said, ‘a Sea-chestnut; I’ve eaten them at
Constantinople!’

And he explained as best he could what a Sea-urchin is. The woman did
not understand a word of what he said and persisted in her contention.
She was convinced that Favier was deceiving her, jealous at the thought
that such precious seeds should reach me through any other intermediary
than him. The issue was submitted to me.

‘Vaqui la flou, vaqui lou pécou,’ repeated the good woman.

I told her that the flou was the cluster formed by the Urchin’s five
white teeth and that the pécou was the antipodes of the mouth. She went
away only half convinced. It may be that, at this moment, the seeds of
the fruit, grains of sand rattling in the empty shell, are germinating
in some old broken-mouthed pipkin.

Favier, therefore, knows many things; and he knows them more
particularly through having eaten them. He knows the virtues of a
Badger’s back, the toothsome qualities of the leg of a Fox; he is an
expert as to the best part of that Eel of the bushes, the Snake; he has
browned in oil the Eyed Lizard, the ill-famed Rassade of the South; he
has thought-out the recipe of a fry of Locusts. I am astounded at the
impossible stews which he has concocted during his cosmopolitan career.

I am no less surprised at his penetrating eye and his memory for
things. I have only to describe some plant, which to him is but a
nameless weed, devoid of the least interest; and, if it grows in our
woods, I feel pretty sure that he will bring it to me and tell me the
spot where I can pick it for myself. The botany of the infinitesimal
even does not foil his perspicacity. To complete my already-published
work on the Sphæriaceæ of Vaucluse, I resume my patient herborizing
with the lens during the bad weather, the insect’s slack time. When the
frost hardens the ground, when the rains reduce it to slush, I take
Favier away from his work in the garden to scour the woods with me; and
there, in the tangle of some bramble-bush, we hunt together for those
microscopic growths which speckle with black dots the tiny branches
strewn all over the soil. He calls the largest species ‘gunpowder,’ an
accurate expression which has already been used by the botanists to
describe one of those Sphæriaceæ. He feels quite proud of his bunch of
discoveries, which is richer than mine. When he lights upon a
magnificent rosellinia, a mass of black pustules wrapped in a purplish
down, we smoke a pipe to celebrate the joyous occasion.

He excels, above all things, in ridding me of the troublesome folk whom
I meet upon my rambles. The peasant is naturally curious, as fond of
asking questions as a child; but his curiosity is flavoured with a
spice of malice and in all his questions there is an undercurrent of
chaff. What he fails to understand he turns into ridicule. And what can
be more ludicrous than a gentleman looking through a glass at a Fly
captured with a gauze net, or a bit of rotten wood picked up from the
ground? Favier cuts short the bantering catechism with a word.

We were hunting along the ground, step by step, with bent backs, for
some of the evidences of prehistoric times that abound on the south
side of the mountain: serpentine-stone axes, black potsherds, flint
arrow-heads and spear-heads, flakes, side-scrapers, cores.

‘What does your master do with those ‘payrards?’ [44] asked a new
arrival.

‘He makes them into putty for the glaziers,’ replied Favier, with an
air of solemn assurance.

Another time, I had just gathered a handful of Rabbit-droppings in
which the magnifying-glass had shown me a cryptogamous growth worthy of
further inspection. Up comes an inquisitive person who has seen me
carefully packing the precious windfall in a paper bag. He suspects a
money-making business, some crazy trade or other. Everything, to the
countryman, is translatable into terms of francs and sous. In his eyes,
I am making a steady income out of these Rabbit-droppings.

‘What does your master do with those pétourles?’ [45] he asks Favier,
in ingratiating tones.

‘He distils them to extract the essential oils,’ replies my man, with
magnificent self-possession.

Stunned by this revelation, the questioner turns his back and goes
away.

But let us waste no more time with the waggish old soldier and his
smart repartees and let us rather come to what was attracting my
attention in the harmas laboratory. Some Ammophilæ were exploring on
foot, with brief intervals of flight, both the grass and the bare
patches of ground. I had seen them as early as the middle of March,
when a fine day made its appearance, warming themselves luxuriously in
the dusty paths. All belonged to the same species, the Hairy Ammophila
(A. hirsuta, Kirb.). I have already written of the hibernation of this
Ammophila and her venery in mid-spring, at a period when the other
Hunting Wasps are still imprisoned in their cocoons; I have described
her manner of operating on the caterpillar destined for her grub; I
have told of the repeated stings of her dart, distributed over the
different nerve-centres. This scientific vivisection I had as yet
observed but once; and I longed to see it again. Something might have
escaped me on the first occasion, when a long walk had tired me; and,
even if I had really seen everything correctly, it was advisable to
witness the performance a second time, so as to establish its
authenticity beyond all doubt. I may add that one would never weary of
the spectacle, even if it were repeated a hundred times over.

I therefore watched my Ammophilæ from the moment of their first
appearance; and, as I had them here, within my precincts, only a few
steps from my door, I could not fail to catch them hunting, provided
that my assiduity were not relaxed. The end of March and the whole of
April were spent in vain waiting, either because the moment of
nidification had not yet come, or, more probably, because my vigilance
was at fault. At last, on the 17th of May, a lucky chance presented
itself.

A few Ammophilæ strike me as very busy: suppose we follow one of them,
more active than the rest. I detect her giving a last sweep of the rake
to her burrow, on the smooth, hard path, before introducing her
caterpillar, which, already paralysed, must have been abandoned by the
huntress, for the time being, a few yards away from the home. The cave
is pronounced spick and span, the doorway deemed sufficiently wide to
admit a bulky prey; and the Ammophila sets off in search of her
captive. She finds it easily. It is a Grey Worm, lying on the ground;
and the Ants have already invaded it. This prize, for which the Ants
contend with her, is scorned by the huntress. Many predatory Wasps, who
temporarily leave their prisoner to go and complete the burrow, or even
to begin it, lodge their game high up, on a tuft of verdure, to place
it beyond the reach of plunderers. The Ammophila is familiar with this
prudent practice; but perhaps she has omitted to take the precaution,
or else the heavy prize has fallen to the ground, and now the Ants are
tugging in eager rivalry at the sumptuous fare. To drive away those
pilferers is impossible: for one sent to the right-about, ten would
return to the attack. So the Wasp seems to think; for, realizing the
invasion, she resumes her hunting, without indulging in useless strife.

The quest takes place within a radius of ten yards from the nest. The
Ammophila explores the soil on foot, little by little, without
hurrying; she lashes the ground continually with her antennæ curved
like a bow. The bare soil, the pebbly bits, the grassy parts are
visited without distinction. For nearly three hours, in the heat of the
sun, in sultry weather which means rain to-morrow and a few drops
to-night, I watch the Ammophila’s search, without taking my eyes from
her for a second. What a difficult thing a Grey Worm is to find, for a
Wasp who needs it just at that moment!

It is no less difficult for man. The reader knows my method of
witnessing the surgical operation to which a Hunting Wasp subjects her
prey, with a view to giving her grubs flesh that is lifeless but not
dead. I rob the marauder of her spoil and, in exchange, give her a live
prey, similar to her own. I was arranging the same manœuvre with regard
to the Ammophila, so that, after she had smitten her caterpillar, which
she was bound to find at any moment now, I might make her perform the
operation a second time. I was therefore in urgent need of a few Grey
Worms.

Favier was there, gardening. I called out to him:

‘Come here, quick; I want some Grey Worms!’

I explain the thing to him; for that matter, he has known all about it
for some time. I have talked to him of my little creatures and the
caterpillars which they hunt; he has a general knowledge of the habits
of the insect which I am studying. He understands at once and goes in
search. He digs at the foot of the lettuces, he scrapes among the
strawberry-beds, he inspects the iris-borders. I know his sharp eyes
and his intelligence; I have every confidence in him. Meanwhile, time
passes.

‘Well, Favier? Where’s that Grey Worm?’

‘I can’t find one, sir.’

‘Bother! Then come to the rescue, you others! Claire, Aglaé, all of
you! Hurry up, hunt and find!’

The whole family is brought into requisition. All its members display
an activity worthy of the serious events at hand. I myself, chained to
my post lest I should lose sight of the Ammophila, keep one eye upon
the huntress and with the other watch for Grey Worms. Nothing turns up:
three hours pass and not one of us has found the caterpillar.

The Ammophila does not find it either. I see her hunting with some
persistency in spots where the earth is slightly cracked. The insect
wears itself out in clearing operations; with a mighty effort it
removes lumps of dry earth the size of an apricot-stone. Those spots
are soon abandoned, however. Then a suspicion comes to me: the fact
that there are four or five of us vainly hunting for a Grey Worm does
not prove that the Ammophila is troubled with the same want of skill.
Where man is helpless, the insect often triumphs. The exquisite
delicacy of perception that guides it cannot leave it at a loss for
hours together. Perhaps the Grey Worm, foreseeing the gathering storm,
has dug its way lower down. The huntress very well knows where it lies,
but cannot extract it from its deep hiding-place. When she abandons a
spot after a few attempts, it is not for want of sagacity, but for want
of the requisite power of digging. Wherever the Ammophila scratches,
there must a Grey Worm be: the place is abandoned because the work of
extraction is admittedly beyond her strength. It was very stupid of me
not to have thought of it earlier. Would such an experienced poacher
pay any attention to a place where there is really nothing? What
nonsense!

I thereupon resolve to come to her assistance. The insect, at this
moment, is digging a tilled and absolutely bare spot. It leaves the
place, as it has already done with so many others. I myself continue
the work, with the blade of a knife. I do not find anything either; and
I retire. The insect comes back and again begins to scratch at a
certain part of my excavations. I understand:

‘Get out of that, you clumsy fellow!’ the Hymenopteron seems to say.
‘I’ll show you where the thing lives!’

Upon her indications I dig at the required spot and unearth a Grey
Worm. Well done, my canny Ammophila! Did I not say that you would never
have raked at an empty burrow?

Henceforth, it is like a hunt for truffles, which the Dog points out
and the man extracts. I continue on the same system, the Ammophila
showing me the place and I digging with the knife. I thus obtain a
second Grey Worm, followed by a third and a fourth. The exhumation is
always effected at bare spots that have been turned by the pitchfork a
few months earlier. There is absolutely nothing to denote the presence
of the caterpillar from without. Well, Favier, Claire, Aglaé and the
rest of you, what have you to say? In three hours you have not been
able to dig me up a single Grey Worm, whereas this clever huntress
supplies me with as many as I want, once that I have thought of coming
to her assistance!

I have now plenty of spare pieces; let us leave the huntress her fifth
prize, which she unearths with my help. I will set forth in numbered
paragraphs the various acts of the gorgeous drama that passes before my
eyes. The observation is made under the most favourable conditions: I
am lying on the ground, close to the slaughterer, and not one detail
escapes me.

1. The Ammophila seizes the caterpillar by the back of the neck with
the curved pincers of her mandibles. The Grey Worm struggles violently,
rolling and unrolling its contorted body. The Wasp remains quite
unconcerned: she stands aside and thus avoids the shocks. Her sting
strikes the joint between the first segment and the head, on the median
ventral line, at a spot where the skin is more delicate. The dart stays
in the wound with some persistency. This, it appears, is the essential
blow, which will master the Grey Worm and make it more easy to handle.

2. The Ammophila now quits her prey. She flattens herself on the
ground, with wild, disordered movements, rolling on her side, twitching
and dangling her limbs, fluttering her wings, as though in danger of
death. I fear lest the huntress may have received a nasty wound in the
contest. I am overcome with emotion at seeing the plucky Wasp finish so
piteously, at seeing the experiment that has cost me so many hours of
waiting end in failure. But suddenly the Ammophila recovers, smooths
her wings, curls her antennæ and returns briskly to the attack. What I
had taken for the convulsions of approaching death was the frenzied
enthusiasm of victory. The Wasp was congratulating herself on the
manner in which she had floored the enemy.

3. The operator grips the caterpillar by the skin of the back, a little
lower than before, and pricks the second segment, still on the ventral
surface. I then see her gradually recoiling along the Grey Worm, each
time seizing the back a little lower down, clasping it with the
mandibles, those wide pincers with the curved jaws, and each time
driving the sting into the next segment. This recoil of the insect and
this gradual clasping of the back, a little farther down on each
occasion, are effected with methodical precision, as though the
huntress were measuring her prey. At each step backward the dart stings
the following segment. In this way are wounded the three thoracic
segments, with the true legs; the next two segments, which are legless;
and the four segments with the pro-legs. In all, nine stings. The last
four segments are disregarded: they consist of three without legs and
the last, or thirteenth, with pro-legs. The operation is accomplished
without serious difficulty: after the first prick of the needle, the
Grey Worm offers but a feeble resistance.

4. Lastly, the Ammophila, opening the forceps of her mandibles to their
full width, seizes the caterpillar’s head and crunches it, squeezes it
with a series of leisurely movements, without creating a wound. These
squeezings follow upon one another with deliberate slowness: the insect
seems to try each time to learn the effect produced; it stops, waits,
and then resumes the attack. This manipulation of the brain, to attain
the desired end, must have certain limits which, if exceeded, would
bring about death and speedy putrefaction. And so the Wasp regulates
the force of her compressions, which, moreover, are numerous: about a
score, in all.

The surgeon has finished. The patient lies on the ground on its side,
half doubled up. It is motionless, lifeless, incapable of resistance
during the traction-process that is to bring it home, unable to harm
the grub that is to feed upon it. The Ammophila leaves it at the place
where the operation was performed and goes back to her nest. I follow
her. She makes certain improvements in view of the coming storage. A
pebble projecting from the roof might impede the warehousing of the
bulky quarry. The lump is forthwith removed. A rustle of grazed wings
accompanies the arduous task. The back-room is not large enough: it is
widened. The work is long-drawn-out; and the caterpillar, which I have
neglected to watch, lest I should miss any of the Wasp’s doings, is
invaded by the Ants. When the Ammophila and I return to it, it is black
all over with busy carvers. This is a regrettable incident for me and a
grievous event for the Ammophila; for it is the second time that she
has met with the same mishap.

The insect appears discouraged. In vain I replace the caterpillar by
one of my reserve of Grey Worms: the Ammophila scorns the substituted
prey. Besides, evening is drawing in, the sky has clouded, there are
even a few drops of rain falling. In these circumstances it is needless
to look for a renewal of the chase. Everything, therefore, ends,
without my being able to use my Grey Worms as I had proposed.

This observation kept me engaged, without a moment’s respite, from one
o’clock in the afternoon until six o’clock in the evening.



CHAPTER XIX

AN UNKNOWN SENSE


I have described the Ammophila’s hunting tactics in detail. The facts
which I ascertained seem to me so rich in results that, even if the
harmas laboratory supplied me with nothing more, I should think myself
indemnified by this one observation. The surgical methods adopted by
the Wasp with the object of paralysing the Grey Worm are the highest
manifestation in the realm of instinct that I have hitherto met. This
inborn science is eminently calculated to give us food for thought.
What a subtle logician, what an unerring operator is that unconscious
physiologist, the Ammophila!

He who would witness these marvels for himself can hardly count on what
a country walk may happen to show him; besides, if the lucky
opportunity did present itself, he would not have time to profit by it.
An observation, which I kept up for five hours on end, without even
then managing to complete the experiment and obtain the proofs which I
anticipated, is one that, to be properly conducted, should be made at
leisure in one’s own garden. I owe my success, therefore, to my rustic
laboratory. I make a present of the secret to whosoever would continue
those magnificent studies: the harvest is inexhaustible; there will be
sheaves for all.

When we follow the Ammophila’s hunting in the due sequence of her
actions, the first question that suggests itself is this: how does the
Wasp go to work to recognize the spot beneath which the Grey Worm lies?

There is nothing outside, nothing, at least, perceptible to the eye, to
indicate the caterpillar’s hiding-place. The soil that conceals the
quarry may be grassy or bare, flinty or earthy, smooth or seamed with
little cracks. These varieties of appearance are matters of
indifference to the huntress, who prospects every spot without showing
preference for one more than another. At no place where the Wasp stops
and digs with some persistency do I see anything particular, in spite
of all my attention; and yet there must be a Grey Worm there, as I have
but now convinced myself, five times in succession, by lending a
helping hand to the insect, which was at first discouraged by a task
out of proportion to its strength. Sight, therefore, is certainly out
of the question here.

What sense, then? That of touch? Let us inquire. Everything tells us
that the organs of search are the antennæ. With their tips, bent like a
bow and quivering with a continual vibration, the insect tests the
ground, giving a number of little taps. When some crack shows, the
restless threads enter and sound it; when some grass-tuft spreads its
tangled root-stock along the ground, the quivering of the antennæ
redoubles as they grope among its knots and angles. Their tips are
applied for an instant to the spot explored, moulding themselves, so to
speak, upon it. They suggest two tactile filaments, two long fingers of
incomparable mobility, which gather information by feeling. But the
sense of touch can play no part in revealing what is underground: the
thing to be felt is the Grey Worm; and the worm is lying snug in its
burrow, at a depth of some inches below the surface.

We thereupon turn our thoughts to the faculty of scent. Insects, there
is no denying, possess the sense of smell, often very highly developed.
The Necrophori, [46] the Silphæ, [47] the Histers, [48] the Dermestes
[49] hasten from every side to the spot where lies a little corpse of
which the ground is to be purged. Guided by scent, these grave-diggers
hurry towards the dead Mole.

But, while the presence of the olfactory sense in insects is
indisputable, we still ask ourselves where it is seated. Many declare
that the seat is in the antennæ. Let us admit this, though it is
difficult to understand how a rod consisting of horny segments, jointed
end to end, can fulfil the office of a nostril which is so very
differently constructed. The organization of one apparatus having
naught in common with the other, can the impressions received by both
be of the same nature? When tools are dissimilar, do their functions
remain alike?

Besides, there are grave objections in the case of our Wasp. Smell is a
passive rather than an active sense; it does not, like touch,
anticipate the impression: it receives it; it does not inquire after
the scented effluvium: it accepts it when it comes. Now the Ammophila’s
antennæ are always moving: they investigate, they anticipate the
impression. The impression of what? If it were really an impression of
smell, repose would serve them better than a perpetual quivering.

But there is more to be said: the olfactory sense goes for nothing when
there is no smell. Now I have tested the Grey Worm for myself; I have
given it to young nostrils to sniff, nostrils much more sensitive than
mine: not one of us has perceived the faintest trace of smell in the
caterpillar. When the Dog, famed for his scent, becomes aware of the
truffle underground, he is guided by the tuber’s savour, which is
highly appreciable by ourselves, even through the thickness of the
soil. I admit that the Dog has a more subtle sense of smell than we
have: it is exercised at greater distances, it receives more vivid and
lasting impressions; nevertheless, it is impressed by odorous effluvia
which becomes perceptible to our own nostrils under the proper
conditions of proximity.

I will allow the Ammophila, if you like, a scent as delicate as that of
the Dog, more delicate even; but still a smell is needed; and I ask
myself how that which is inodorous at the very entrance to our nostrils
can be odoriferous to an insect through the intervening obstacle of the
ground. The senses, if they have the same functions, have the same
excitants, from man to the Infusoria. No animal, so far as I know, can
see clearly in what to us is absolute darkness. True, it may be said
that, in the zoological progression, perception, always fundamentally
the same, has varying degrees of power: this species is capable of more
and that species of less; what is perceptible to one is imperceptible
to another. This is perfectly right; and yet the insect, generally
considered, does not appear to possess exceptional keenness of scent:
the effluvia that attract it are perceived without a sense of smell of
unusual delicacy. When Dermestes, Silphæ and Histers pour into the
chalice of a carrion-scented arum lily, never to come out again; when
swarms of Flies buzz around a dead Dog’s blue and swollen belly, the
whole neighbourhood reeks with the stench. It hardly requires a scent
of exquisite accuracy on the insect’s part to discover putrid meat and
rotten cheese. Wherever we see its hordes gather, with scent for their
undoubted guide, we ourselves are cognizant of a smell.

There remains hearing. This is another sense about which entomologists
are not adequately informed. Where is its seat? In the antennæ, we are
told. Those fine, quivering stalks would seem fairly well suited to be
put in motion under the impulse of sound. In that case the Ammophila,
exploring the region with her antennæ, would be warned of the presence
of the Grey Worm by a slight noise coming up from the ground, the noise
of the mandibles nibbling a root, the noise of the caterpillar
wriggling its hind-quarters. What a faint sound and how difficult to
transmit through the spongy cushion of the earth!

It is less than faint, it is non-existent. The Grey Worm is nocturnal
in its habits. By day it skulks in its lair and does not stir. It does
not nibble either; at least, the Grey Worms which I unearthed upon the
Wasp’s indications were nibbling nothing, for the very simple reason
that they had nothing to nibble. They were completely motionless and
therefore silent in a layer of earth devoid of roots. The sense of
hearing must be rejected with that of smell.

The question recurs, more abstruse than ever. How does the Ammophila go
to work to recognize the spot beneath which the Grey Worm lies? The
antennæ are, beyond a doubt, the organs that guide her. They do not, in
this case, act as olfactory instruments, unless we admit that their dry
and tough surface, which has none of the delicate structure required
for the ordinary sense of smell, is nevertheless capable of perceiving
scents that are non-existent to us. This would be equivalent to
admitting that coarse tools tend to perfection of work. Nor do they act
as instruments of hearing, for there is no sound to be discerned. What
then is their function? I do not know and I despair of ever knowing.

Inclined as we are—and it could not well be otherwise—to judge all
things by our standard, the only one in any way known to us, we
attribute to animals our own means of perception and do not dream that
they might easily possess others of which it is impossible for us to
have an exact idea because there is nothing like them in ourselves. Are
we quite certain that they are not equipped, in very varying degrees,
for the purpose of sensations as foreign to ourselves as the sensation
of colours would be if we were blind? Has matter no secrets left for
us? Are we so very sure that it is revealed to the living being only by
light, sound, taste, smell and touch? Physics and chemistry, young
though they be, already declare to us that the dark unknown contains an
enormous harvest, in comparison with which our scientific sheaf is the
merest penury. A new sense, perhaps that which dwells in the
grotesquely exaggerated nose of the Rhinolophus, [50] perhaps that
which dwells in the antennæ of the Ammophila, would open to our search
a world which our physical structure no doubt condemns us to leave for
ever unexplored. Cannot certain properties of matter, which have no
perceptible action upon us, find a receptive echo in animals, which are
differently equipped?

When Spallanzani, [51] after blinding some Bats, released them in a
room converted into a maze by means of cords stretched in every
direction and of heaped-up brambles, how were those animals able to
find their way about, to fly quickly, to move to and fro, from end to
end of the room, without hitting the interposed articles? What sense
analogous to any of ours guided them? Would some one tell me and, above
all, make me understand? I should also like to understand how the
Ammophila infallibly finds her caterpillar’s burrow with the aid of her
antennæ. It is not a case of the sense of smell: we should have to
presume it to possess an unparalleled delicacy, while recognizing that
it is exercised by an organ in which no provision seems made for the
perception of smells.

What a number of other incomprehensible things do we not ascribe to the
insect’s sense of smell! We are satisfied with a word: the explanation
is ready-found, without laborious search. But, if we care to consider
the matter thoroughly, if we compare the requisite array of facts, then
the cliff of the unknown rises abruptly, not to be climbed by the path
which we insist on following. Let us then change our path and admit
that animals may have other means of information than our own. Our
senses do not represent the sum total of the methods whereby an animal
communicates with that which is not itself: there are others not
capable of comparison, however remote, with those which we possess.

If the act of the Ammophila were an isolated fact, I should not have
lingered over it as I have done; but I propose to speak of others
stranger still, which will carry conviction to the most exacting mind.
After relating them, therefore, I shall return to the subject of
special senses, irreducible senses, unknown to us.

For the moment, let us go back to the Grey Worm, which it would be as
well for us to know in a less casual fashion. I have four of them, dug
up with the knife at the spots indicated by the Ammophila. My intention
was to substitute them, by turns, for the doomed victim, so as to see
the Wasp’s operation repeated. When my plan failed, I placed the worms
in a glass jar, with a layer of earth and a lettuce-stalk above them.
By day, my captives remained buried in the earth; at night, they came
up to the surface, where I caught them gnawing at the salad from below.
In August, they dug deep down, not to come up again, and fashioned
themselves a cocoon apiece of earth, very rough on the outer surface,
oval in shape and the size of a small pigeon’s egg. The moth appeared
at the end of the same month. I recognized the Dart or Turnip Moth
(Noctua segetum, Hübn.).

The Hairy Ammophila, therefore, feeds her grubs on the caterpillars of
Noctuæ; and her choice falls exclusively on the species that live
underground. These caterpillars, commonly known as Grey Worms, because
of their drab garb, are a most formidable scourge to agricultural
crops, as well as to garden produce. Curled in their burrows by day,
they climb to the surface at night and gnaw the base or collar of the
herbaceous plants. Everything suits them: ornamental plants and edible
plants alike. Flower-beds, market-gardens, fields are laid waste
without distinction. When a seedling withers without apparent cause,
draw it to you gently; and the dying plant will come up, but maimed,
severed from its root. The Grey Worm has passed that way in the night;
its greedy mandibles have performed the deadly amputation. Its havoc
rivals that wrought by the White Worm, the grub of the Cockchafer. When
it swarms in a beet-country, the damage amounts to millions. This is
the terrible enemy against which the Ammophila comes to our aid.

I point out and urgently recommend to agriculturalists this valuable
auxiliary, so zealous in her search of the Grey Worm in spring, so
skilful in discovering its hiding-place. An Ammophila in a garden may
mean the saving of a lettuce-bed, the snatching of a balsam-border from
danger. But there is need here for recommendations. None would dream of
destroying the pretty Wasp that goes fluttering nimbly from one path to
the other, that visits this corner of the garden, then that, then the
next, then the one over there; none dreams either—and none,
unfortunately, can dream—of assisting her to multiply.

In the immense majority of cases the insect evades our influence: to
exterminate it, if it be harmful, to propagate it, if it be useful, are
impracticable undertakings for us. By a singular contrast of strength
and weakness, man cuts through the neck of continents to join two seas,
he pierces the Alps, he weighs the sun; and yet he cannot prevent a
wretched maggot from enjoying his cherries before he himself does, nor
an odious Louse from destroying his vines! The Titan is vanquished by
the pigmy.

Now we have here, in this insect-world, an auxiliary of high merit, the
supreme foe of our grievous foe the Grey Worm. Can we do anything to
stock our fields and gardens with it at will? We cannot; for the first
condition of multiplying the Ammophila would be to multiply the Grey
Worm, the only food of her family of grubs. I do not speak of the
insurmountable difficulties which this breeding would present. We have
not to do with the Bee, who is faithful to her hive, because of her
social habits; still less with the stupid Silkworm, perched on its
mulberry-leaf, or its clumsy Moth, who for a moment flutters her wings,
pairs, lays her eggs and dies: we have to do with an insect that is
capricious in its wanderings, swift of flight and independent in its
ways.

Besides, the first condition shatters all our hopes. Would we have the
helpful Ammophila? Then we must resign ourselves to accepting the Grey
Worm. We move in a vicious circle: to produce good we must invoke the
aid of evil. The hostile band brings the friendly troop to our fields;
but the second cannot live without the first; and the two show an even
balance in numbers. If the Grey Worm abound, the Ammophila finds
copious provender for her grubs and her race prospers; if the Grey Worm
be rare, the Ammophila’s offspring decrease and disappear. This balance
between prosperity and decadence is the immutable law that governs the
proportions between devourers and devoured.



CHAPTER XX

THE MODERN THEORY OF INSTINCT


The larvæ of the various Hunting Wasps require their prey to be
incapable of movement, so that there may be no resistance on the
victim’s part, which would be a source of danger to the fragile egg
and, later, to the grub. Moreover, for all its lethargy, it must still
be alive; for the grub would refuse to feed on a corpse. The fare
provided must be fresh meat and not preserved stuff. I have already
laid stress on these two antagonistic conditions, immobility and life,
and enlarged on them so fully that I need hardly dwell upon them for a
second time. I have shown how the Wasp realizes them by the medium of a
paralysis which destroys movement and leaves the organic principle of
life intact. With a skill which our most famous vivisectors would envy,
the insect drives its poisoned sting into the nerve-centres, the seat
of muscular incitation. The operator confines herself to one stroke of
the lancet, or else gives two, three or more, according to the
structure of the particular nervous system and to the number and
grouping of the ganglia. The course of the sting is determined by the
exact anatomy of the victim.

The particular prey of the Hairy Ammophila is a caterpillar, each of
whose nerve-centres, which are distant one from the other and to a
certain extent independent in their action, occupies a different
segment of the insect. This caterpillar, who is a very lively customer,
cannot be stored in the cell, with the Wasp’s egg upon his flank, until
he has lost all his power of motion. One movement of his body would
crush that egg against the wall of the cell.

Now the paralysis of one segment would not mean that the next was also
rendered incapable of movement, because of the comparative independence
of the seats of innervation. It is necessary, therefore, that all the
segments, or at least the most important, be operated on, one after the
other, from the first to the last. The course which the Ammophila
adopts is that which the most experienced of physiologists would
recommend: her sting is transferred from one segment to the next, nine
separate times over.

She does better than that. The victim’s head is still unscathed, the
mandibles are at work: they might easily, as the insect is borne along,
grip some bit of straw in the ground and successfully resist this
forcible removal; the brain, the primary nervous centre, might provoke
a stubborn contest, which would be very awkward with so heavy a burden.
It is well that these hitches should be avoided. The caterpillar,
therefore, must be reduced to a state of torpor which will deprive him
of the least inclination for self-defence. The Ammophila succeeds in
effecting this by munching his head. She takes good care not to use her
needle: she is no clumsy bungler and knows quite well that to inflict a
mortal wound on the cervical ganglia would mean killing the caterpillar
then and there, the very thing to be avoided. She merely squeezes the
brain between her mandibles, calculating every pinch; and, each time,
she stops to ascertain the effect produced, for there is a nice point
to be achieved, a certain degree of torpor that must not be exceeded,
lest death should supervene. In this way the requisite lethargy is
obtained, a somnolence in which all volition is lost. And now the
caterpillar, incapable of resistance, incapable of wishing to resist,
is seized by the nape of the neck and dragged to the nest. Comment
would mar the eloquence of such facts as these.

The Hairy Ammophila has twice allowed me to attend her surgical
operations. I have described in an earlier chapter of this volume my
first observation, which dates many years back. On that occasion I
witnessed the performance quite unexpectedly; to-day, I have made all
my preparations and have plenty of time at my disposal, so that I am
able to make a much more thorough observation. In each case there was a
multiplicity of needle-pricks, which were distributed methodically,
from front to back, along the ventral surface. Is the number of stings
indeed identical in both cases? This time, it is exactly nine. In the
case of the victim which I saw paralysed on the Plateau des Angles, it
seemed to me that the weapon inflicted more wounds, though I am not
able to state the precise number. It is quite possible that this number
varies slightly and that the last segments of the caterpillar, being
much less important than the others, are attacked or left alone
according to the size and strength of the quarry to be incapacitated.

On the second occasion, moreover, I had my first view of the squeezing
process to which the caterpillar’s brain is subjected, a process that
produces the torpor which makes the transport and storage of the victim
possible. So remarkable a fact would not have escaped me in the first
instance; it did not, therefore, take place. It follows that this
cerebral compression is a resource which the Wasp has at her disposal,
for use when circumstances demand it, as for instance when the victim
seems likely to offer resistance on the road.

The malaxation of the cervical ganglia is optional: it has no bearing
on the future of the larva; the Wasp practises it, when needful, to
facilitate transport. I have seen the Languedocian Sphex, who gave me
so much trouble in the old days, at work fairly often, but only once
has she performed this operation on the neck of her Ephippiger in my
presence. The invariable and absolutely necessary part of the Hairy
Ammophila’s procedure seems therefore to be the multiplicity of stings
and their distribution one by one over all or nearly all the
nerve-centres along the median line of the lower surface.

Let us place side by side with the murderous art of the Wasp the
murderous art of man, practical man, whose business it is to slay
rapidly. I will here recall one of my childhood’s memories. We were
schoolboys of twelve years old, or thereabouts. We were being
instructed in the woes of Melibœus, pouring out his sorrows on the
bosom of Tityrus, who offers him his chestnuts, his sour milk and his
bed of fresh bracken; [52] we were made to recite a poem by Racine the
Younger, [53] La Religion. A curious poem, forsooth, for children who
cared more for marbles than theology! I remember just two lines and a
half:


          ... et, jusque dans la fange,
        L’insecte nous appelle et, certain de son prix,
        Ose nous demander raison de nos mépris. [54]


Why do these two lines and a half linger in my memory and none of all
the rest? Because already Scarabæus and I were friends. Those two lines
and a half bothered me: I thought it a very absurd idea to relegate you
to the mire, ye insects so seemly clad, so elegantly groomed. I knew
the bronze harness of the Carabus, the Russia-leather jerkin of the
Stag-beetle; I knew that the least of you possesses an ebon sheen and
gleams of precious metals; and therefore the mire wherein the poet
flung you shocked me somewhat. If M. Racine Junior had nothing better
to say about you, he might as well have held his tongue; but he did not
know you, and in his day there were only just a few who were beginning
to have a dim conception of your nature.

While going over some passage of the tiresome poem for the next day’s
lesson, I would indulge my fancy for another kind of education. I
visited the Linnet in her nest, on a juniper-bush standing as high as
myself; I watched the Jay picking an acorn on the ground; I came upon
the Crayfish, still quite soft after shedding his shell; I made
inquiries as to the exact date when the Cockchafers were due; I went in
quest of the first full-blown Cuckoo-flower. Plants and animals, that
wondrous poem of which a faint echo was beginning to wake in my young
brain, made a very pleasant change from the uninspiring alexandrine.
The problem of life and that other one, with its dark terrors, the
problem of death, at times passed through my mind. It was a fleeting
obsession, soon forgotten by the mercurial spirits of youth.
Nevertheless, the tremendous question would recur, brought to mind by
this incident or that.

Passing one day by a slaughter-house, I saw an Ox driven in by the
butcher. I have always had an insurmountable horror of blood; when I
was a boy, the sight of an open wound affected me so much that I would
fall into a swoon, which on more than one occasion nearly cost me my
life. How did I screw up courage to set foot in those shambles? No
doubt, the dread problem of death urged me on. At any rate, I entered,
close on the heels of the Ox.

With a stout rope round its horns, wet-muzzled, meek-eyed, the animal
moves along as though making for the crib in its stable. The man walks
ahead, holding the rope. We enter the hall of death, amid the sickening
stench thrown up by the entrails scattered over the ground and the
pools of blood. The Ox becomes aware that this is not his stable; his
eyes turn red with terror; he struggles; he tries to escape. But an
iron ring is there, in the floor, firmly fixed to a stone flag. The man
passes the rope through it and hauls. The Ox lowers his head; his
muzzle touches the ground. While an assistant keeps him in this
position with the rope, the butcher takes a knife with a pointed blade,
not at all a formidable knife, hardly larger than the one which I
myself carry in my breeches-pocket. For a moment he feels with his
fingers at the back of the animal’s neck and then drives in the blade
at the chosen spot. The great beast gives a shiver and drops, as though
struck by lightning: procumbit humi bos, as we used to say in those
days.

I fled from the place like one possessed. Afterwards I wondered how it
was possible, with a knife almost identical with that which I used for
prizing open my walnuts and taking the skin off my chestnuts, with that
insignificant blade, to kill an Ox and kill him so suddenly. No gaping
wound, no blood spilt, not a bellow from the animal. The man feels with
his finger, gives a jab and the thing is done: the Bullock’s legs
double up under him.

This instantaneous death, this lightning-stroke, remained an awesome
mystery to me. It was only later, very much later, that I learnt the
secret of the slaughter-house, at a time when, in the course of my
promiscuous reading, I was picking up a smattering of anatomy. The man
had cut through the spinal marrow where it leaves the skull; he had
severed what our physiologists have called the vital cord. To-day I
might say that he had operated in the manner of the Wasps, whose lancet
plunges into the nerve-centres.

Let us watch this spectacle a second time, under more exciting
conditions: I mean, in the saladeiros of South America, those immense
establishments for killing and treating meat, where they slaughter as
many as twelve hundred Oxen a day. I will quote the account of an
eye-witness: [55]


    ‘The cattle arrive in large herds and the matance begins on the day
    after the arrival. A whole herd is confined in an enclosed space,
    or margueira. From time to time men on horseback drive fifty or
    sixty beasts into a narrower and stronger enclosure, with a sloping
    floor of brick, boards or concrete, which is always very slippery.
    A special operator, standing on an outer platform which runs along
    the wall of the smaller margueira, lassoes one of the crowd of
    animals by the head or, more often, by the horns. The middle
    portion of the long, stout lasso is coiled round a windlass; and a
    draught-horse, or sometimes a pair of oxen, drags the lassoed beast
    along and makes it slide, in spite of its struggles, right against
    the windlass, where it is brought up with a thud and remains
    without power of movement.

    ‘Another assistant, the desnucador, also standing on the platform,
    has then but to stick a knife, at the back of the head, between the
    occipital bone and the axis; and the paralysed animal topples on to
    a trolley in which it is carted off. It is at once thrown on an
    inclined plane where other special labourers bleed it and skin it.
    But, as the injury to the cervical marrow varies a good deal in
    position and extent, it often happens that the unfortunate beasts
    still retain the motions of the heart and of the respiratory
    organs; and, in such cases, they suffer a reaction under the knife;
    they utter faint sounds of pain and move their limbs, while already
    half-flayed and disembowelled. Nothing could be more painful than
    the sight of all those animals skinned alive, cut up and
    transformed by those men, covered with blood, who run about in all
    directions.’


The murderous methods of the saladeiro are an exact repetition of what
I had seen in the slaughter-house. In both these lethal work-shops they
pierce the vertebral marrow at the base of the skull. The Ammophila
operates in a similar fashion, with this difference, that her surgery
is much more complex, much more difficult, because of the peculiar
organization of her victim. The honours are on her side again when we
consider the delicacy of the result obtained. Her caterpillar is not a
corpse, like the Ox whose spinal cord is cut; it is alive, but
incapable of movement. The insect here is man’s superior in all
respects.

Now how did the butcher of our parts and the desnucador of the pampas
light upon the idea of plunging a knife into the seat of the marrow, in
order to produce the sudden death of a colossus which would never
suffer its throat to be cut without first offering a dangerous
resistance? Outside those in the trade and men of science, nobody knows
or suspects the lightning result of that particular wound; we are
almost all in the same state of ignorance on this subject in which I
myself was when my childish curiosity drew me into the killing-shed.
The desnucador and the butcher have learnt their craft from the
teachings of tradition and example: they have had masters; and these
were brought up in the school of other masters, harking back by a chain
of linked traditions to him who, served, no doubt, by some hazard of
the chase, first realized the tremendous effects of a wound in the nape
of the neck. Who shall tell us that a pointed flint-stone, driven by
accident into the spinal marrow of the Reindeer or the Mammoth, did not
rouse the attention of the desnucador’s forerunner? A casual incident
furnished the original idea; observation confirmed it; reflection
matured it; tradition preserved it; example disseminated it. After
that, the same transmission-current. For generation might follow
generation in vain: deprived of masters, the desnucador’s descendants
would return to the primitive state of ignorance. Heredity does not
hand down the art of killing by severing the spinal marrow: no man is
born a cattle-slayer by the desnucador’s method.

Now here is the Ammophila, a slayer of caterpillars by a far more
cunning method. Where are the professors of the art of stinging? There
are not any. When the Wasp rends her cocoon and issues from
underground, her predecessors have long ceased to live; she herself
will perish without seeing her successors. Once the larder is stocked
and the egg laid, all connection with the offspring ends; this year’s
perfect insect dies while next year’s insect, still in the larval
stage, slumbers below ground in its silken cot. Absolutely nothing,
therefore, is transmitted by practical illustration. The Ammophila is
born a finished desnucador even as we are born feeders at our mother’s
breast. The nurseling uses its suction-pump, the Ammophila her dart,
without ever being taught; and both are past masters of the difficult
art from the first attempt. There we have instinct, the unconscious
impulse that forms an essential part of the conditions of life and is
handed down by heredity in the same way as the rhythmic action of the
heart and lungs.

Let us try, if possible, to trace the Ammophila’s instinct to its
source. We suffer to-day, more than we ever did, from a mania for
explaining what might well be incapable of explanation. There are
some—and their number seems to increase daily—who settle the stupendous
question with magnificent audacity. Give them half-a-dozen cells, a bit
of protoplasm and a diagram for demonstration; and they will account to
you for everything. The organic world, the intellectual and moral
world, everything derives from the original cell, evolving by means of
its own energies. It’s as simple as A B C. Instinct, roused by a chance
action that has proved favourable to the animal, is an acquired habit.
And men argue on this basis, invoking natural selection, heredity, the
struggle for life. I see plenty of big words, but I should prefer a few
small facts. These little facts I have been collecting and catechizing
for nearly forty years; and their replies are not exactly in favour of
current theories.

You tell me that instinct is an acquired habit, that a casual
circumstance, propitious to the animal’s offspring, was the first to
prompt it. Let us look into the thing more closely. If I understand
aright, we must suppose some Ammophila, in a very remote past, to have
accidentally injured her caterpillar’s nervous centres; to have found
herself the gainer by this operation, both as regards herself, in being
released from a struggle not unattended with danger, and as regards her
larva, thus supplied with fresh, living and yet harmless victuals; and
consequently to have endowed her offspring, by heredity, with a natural
tendency to repeat the advantageous device. The maternal legacy did not
benefit all the descendants equally: some were poor hands at the
newborn art of the stiletto; others were adepts. Then came the struggle
for existence, the hateful væ victis! The weak went under, the strong
flourished; and, as age succeeded age, selection by vital competition
changed the fleeting impression of the start into a deep-rooted,
ineffaceable impression, exemplified in the masterly instinct which we
admire in the Wasp to-day.

Well, I avow, in all sincerity, this is asking a little too much of
chance. When the Ammophila first found herself in the presence of her
caterpillar, there was nothing, you would have it, to guide the sting.
The choice was made at random. The pricks were directed at the upper
surface of the captured prey, at the lower surface, at the sides, the
front and the back indiscriminately, according to the fortunes of a
close struggle. The Hive-bee and the Social Wasp sting those points
which they are able to reach, without showing a preference for one part
over the other. That is how the Ammophila must have acted, when still
ignorant of her art.

Now how many points are there in a Grey Worm, above and below?
Mathematical accuracy would answer, an infinity; a few hundreds will
serve our purpose. Of this number, nine or perhaps more have to be
selected; the needle must be inserted there and not elsewhere: a little
higher, a little lower, a little to one side, it would not produce the
desired effect. If the favourable event is a purely accidental result,
how many combinations would be needed to bring it about, how much time
to exhaust all the possible cases? When the difficulty becomes too
pressing, you take refuge behind the mist of the ages; you retreat into
the shadows of the past as far as fancy can carry you; you call upon
time, that factor of which we have so little at our disposal and which,
for this very reason, is so well suited to hide our illusions. Here you
can let yourselves go and lavish the centuries. Suppose we shake up
hundreds of figures, all of different values, in an urn and draw nine
at random. When shall we, in this way, obtain a sequence fixed
beforehand, a sequence that stands alone? The chance is so slight,
answers mathematics, that we may as well put it down as nil and say
that the desired arrangement will never come about. For the Ammophila
of the prehistoric age, the attempt was renewed only at long intervals,
from one year to the next. Then how did this sequence of nine stings at
nine selected points emerge from the urn of chance? When I am driven to
appeal to infinity in time, I am very much afraid of running up against
absurdity.

‘But,’ say you, ‘the insect did not attain its present surgical
dexterity at the outset: it went through experiments, apprenticeships,
varying degrees of skill. There was a weeding-out by natural selection,
eliminating the less expert, retaining the more gifted; and instinct,
as we know it, developed gradually, thanks to the accumulation of
individual capacities, added to those handed down by heredity.’

The argument is erroneous: instinct developed by degrees is flagrantly
impossible in this case. The art of preparing the larva’s provisions
allows of none but masters and suffers no apprentices; the Wasp must
excel in it from the outset or leave the thing alone. Two conditions,
in fact, are absolutely essential: that the insect should be able to
drag home and store a quarry which greatly surpasses it in size and
strength; and that the newly-hatched grub should be able to gnaw
peacefully, in its narrow cell, a live and comparatively enormous prey.
The suppression of all movements in the victim is the only means of
realizing these conditions; and this suppression, to be complete,
requires sundry dagger-thrusts, one in each motor centre. If the
paralysis and the torpor be not sufficient, the Grey Worm will defy the
efforts of the huntress, will struggle desperately on the road and will
not reach the journey’s end; if the immobility be not complete, the
egg, fixed at a given spot on the worm, will perish under the
contortions of the giant. There is no via media, no half-success.
Either the caterpillar is treated according to rule and the Wasp’s
family is perpetuated; or else the victim is only partially paralysed
and the Wasp’s offspring dies in the egg.

Yielding to the inexorable logic of things, we will therefore admit
that the first Hairy Ammophila, after capturing a Grey Worm to feed her
larva, operated on the patient by the exact method in use to-day. She
seized the creature by the skin of the neck, stabbed it underneath,
opposite each of the nerve-centres and, if the monster threatened
further resistance, munched its brain. It must have happened like this;
for, once more, an unskilled murderess, doing her work in a perfunctory
and haphazard fashion, would leave no successor, since the rearing of
the egg would become impossible. Save for the perfection of her
surgical powers, the slayer of fat caterpillars would die out in the
first generation.

Again I hear you say:

‘The Hairy Ammophila, before hunting the Grey Worm, may have picked out
feebler caterpillars and heaped up several in one cell, until they
represented the same bulk of provender as the big prey of to-day. With
puny game, a few thrusts of the needle, perhaps one, would be enough.
Gradually, large-sized prey came to be preferred, as reducing the
number of hunting expeditions. Then, as successive generations went
after bigger game, the dagger-strokes were multiplied, in proportion to
the victim’s power of resistance; and, by degrees, the elementary
instinct of the outset became the highly-developed instinct of our
time.’

To these arguments we may begin by replying that the larva’s change of
diet and the substitution of one morsel for a number are diametrically
opposed to what happens before our eyes. The Hunting Wasp, as we know
her, is extremely loyal to old customs; she has sumptuary laws which
she never transgresses. She who fed on Weevils in her youth puts
Weevils and naught else in her larva’s cell; she who was supplied with
Buprestis-beetles persists in the fare which she has adopted and serves
her larva with Buprestis-beetles. One Sphex must have Crickets; a
second, Grasshoppers; a third, Locusts. Nothing is accepted but these
particular dishes. The Bembex who hunts Gad-flies revels in them and
refuses to do without them, whereas Stizus ruficornis, who fills the
larder with Praying Mantes, scorns any other game. And so with the
rest. They have each their own taste.

It is true that many allow themselves a more varied bill of fare, but
only within the limits of one entomological group: thus the Weevil and
Buprestis hunters prey upon any species proportioned to their strength.
Were the Hairy Ammophila to make a change in her diet, that would be
her case too. Whether small and sundry to each cell or large and
single, the prey would always consist of caterpillars. So far, so good.
But there remains the question of the many replaced by the unit; and I
do not yet know one instance of such an alteration in the Wasp’s
habits. She who stocks the burrow with a single joint never thinks of
heaping up several of smaller size; she who goes on repeated
expeditions to stack a quantity of game in the same cell does not know
how to limit herself to one head by choosing larger meat. The result of
my observations never varies in this regard. The prehistoric Ammophila,
who abandoned her multiplicity of small game for one colossal head, has
nothing to warrant her existence.

If the point were conceded, would the question be advanced? Not in the
least. Let us accept as the initial prey a feeble caterpillar,
paralysed with a single sting. Even then that sting must not be given
at random, else the act would be more harmful than profitable.
Irritated, but not subdued by the wound, the animal would but become
more dangerous. The dart must strike a nerve-centre, probably in the
middle region of the string of ganglia. This, at any rate, is how the
present-day Ammophilæ seem to go to work when they are addicted to the
rape of frail and slender grubs. What chance would the operator have of
striking that one particular point, if her lancet were wielded without
method? The probability is ludicrously remote: it is as one to the
countless number of points whereof the caterpillar’s body is made up.
And yet, according to the theorists, it is on this probability that the
Wasp’s future depends. What an edifice to balance on the point of a
needle!

Let us go on admitting and continue. The desired point is struck; the
prey is duly paralysed; the egg laid on its flank will develop in
safety. Is that enough? It is at most but a half of what is absolutely
necessary. Another egg is indispensable to complete the future couple
and ensure offspring. Therefore, within a few days’, within a few
hours’ interval, a second sting must be given, as successful as the
first. In other words, the impossible has to be repeated, the
impossible raised to the second degree.

Let us not be discouraged yet; let us sound the uttermost depths of the
problem. Here is a Wasp, some precursor, no matter which, of our
Ammophila, who, favoured by chance, has twice and perhaps oftener
succeeded in reducing the prey to that state of inertia which the
rearing of the egg imperatively demands. She does not know, does not
suspect that she inserted her sting opposite a nerve-centre rather than
elsewhere. As there was nothing to prompt her choice, she acted at
random. Nevertheless, if we are to take the theory of instinct
seriously, we shall have to admit that this fortuitous action, though a
matter of indifference to the insect, left a lasting trace and made so
great an impression that, henceforth, the cunning stratagem which
produces paralysis by attacking the nervous centres is transmissible by
heredity. The Ammophila’s successors, by some prodigious privilege,
will inherit what the mother did not possess. They will know by
instinct the point or points towards which the sting must be directed;
for, if they were still in the prentice stage, if they and their
successors had to risk the chance that accident would tend gradually to
strengthen the nascent impulse, they would be going back to the
likelihood so near allied to nil; they would go back to it year by
year, for centuries to come; and yet the one and only favourable chance
would have to be always recurring. I find it very difficult to believe
in a habit acquired by this prolonged repetition of incidents whereof
not one can take place without excluding so many contrary chances. It
is a simple matter of arithmetic to show the number of absurdities
against which the theorists rush headlong.

Nor is this all. We should have to ask ourselves how casual actions, to
which the insect was not predisposed by nature, can become the source
of a hereditary transmissible habit. We should look upon a man as a
sorry wag who came to us and said that the descendant of the desnucador
knows the art of slaughtering cattle from A to Z merely through being
the son of his father, without the aid of precept or example. The
father does not use his blade just once or twice, by accident; he
operates every day and scores of times a day; he goes to work with
reflection. It is his business. Does this lifelong practice create a
transmissible habit? Are the sons, the grandsons, the great-grandsons
any the wiser, without instruction? No, the thing has to start afresh
each time. Man is not predisposed by nature to this butchery.

If, on her side, the Wasp excels in her art, it is because she is born
to follow it, because she is endowed not only with tools, but also with
the knack of using them. And this gift is original, perfect from the
outset: the past has added nothing to it, the future will add nothing
to it. As it was, so it is and will be. If you see in it naught but an
acquired habit, which heredity hands down and improves, at least
explain to us why man, who represents the highest stage in the
evolution of your primitive plasma, is deprived of the like privilege.
A paltry insect bequeaths its skill to its offspring; and man cannot.
What an immense advantage it would be to humanity if we were less
liable to see the worker succeeded by the idler, the man of talent by
the idiot! Ah, why has not protoplasm, evolving by its own energy from
one being into another, reserved until it came to us a little of that
wonderful power which it has bestowed so lavishly upon the insects! The
answer is that apparently, in this world, cellular evolution is not
everything.

For these among many other reasons, I reject the modern theory of
instinct. I see in it no more than an ingenious game in which the
armchair naturalist, the man who shapes the world according to his
whim, is able to take delight, but in which the observer, the man
grappling with reality, fails to find a serious explanation of anything
whatsoever that he sees. In my own surroundings, I notice that those
who are most positive in the matter of these difficult questions are
those who have seen the least. If they have seen nothing at all, they
go to the length of rashness. The others, the timid ones, know more or
less what they are talking about. And is it not the same outside my
modest environment?



APPENDIX


The following Wasps appear to me to be new to our fauna. I give a
description of each of them.



A

CERCERIS ANTONIÆ—H. FAB.

Length, 16 to 18 millimetres. [56] Black, thickly and deeply spotted.
Shield, raised like a nose, that is to say, forming a convex
projection, broad at the base, pointed at the tip and resembling one
half of a cone divided lengthwise. Prominent crest between the antennæ.
A yellow streak above the crest, yellow cheeks and a large yellow spot
behind each eye. Yellow shield, with black dot. Mandibles, iron-yellow,
with black tips. First four or five joints of the antennæ, iron-yellow;
the rest brown.

Two dots on the prothorax, the wing-scales and the postscutellum
yellow. First segment of the abdomen has two round spots. The next four
segments have on their hinder edge a yellow band cut deeply into the
form of a triangle, or even broken right off; and this is more
noticeable in the less distant segments.

Under-part of the body, black. Legs, iron-yellow all through. Wings,
slightly bronzed at the tip.

The above is a description of the female. The male is unknown to me.

In colouring, this species approaches Cerceris labiata, from which it
differs more particularly by the shape of the shield and by its size,
which is much larger. Observed near Avignon in July.

I dedicate this species to my daughter Antonia, whose assistance has
often been of great value to me in my entomological researches.



B

CERCERIS JULII.—H. FAB.

Length, 7 to 9 millimetres. [57] Black, thickly and deeply spotted.
Shield, flat. Face covered with a fine silvery down. A narrow yellow
band on either side on the inner edge of the eyes. Mandibles, yellow,
with brown tips. Antennæ, black above, pale russet below; lower surface
of their basilar joints, yellow.

On the prothorax two small yellow dots, some distance apart; yellow
wing-scales and postscutellum. A yellow band on the third segment of
the abdomen and another on the fifth segment; these two bands are
deeply hollowed on the fore-edge, the first into a semicircle, the
second into a triangle.

Under-part of the body, entirely black. Black hips; thighs of the
hind-legs, all black; those of the two front pairs, black at the root
and yellow at the end. Legs and tarsi, yellow. Wings slightly
smoke-coloured.

Female.

Varieties: 1. Prothorax without yellow dots. 2. Two small yellow dots
on the second segment of the abdomen. 3. Wider yellow band on the inner
side of the eyes. 4. Front of shield edged yellow.

The male is unknown to me.

This Cerceris, the smallest in my district, feeds her larvæ on very
small-sized Weevils, Bruchus granarius and Apion gravidum. Observed
near Carpentras, where she builds her nest in September, in the soft
sandstone locally known as safre.



C

BEMBEX JULII.—H. FAB.

Length, 18 to 20 millimetres. [58] Black, with bristling whitish hairs
on the head, the thorax and the base of the first segment of the
abdomen. Long upper lip, yellow. Ridge-shaped shield, forming a sort of
trihedral angle, of which one side, that of the fore-edge, is all
yellow, while each of the two others is marked with a large rectangular
black patch, touching the adjacent one, so that the two together form a
chevron; these two patches and also the cheeks are covered with a fine
silvery down. Cheeks and a median line between the antennæ, yellow. The
back rim of the eyes has a long yellow border. Yellow mandibles, brown
at the tips. First two joints of the antennæ, yellow underneath, black
above; the others, yellow.

Prothorax, black, with its sides and dorsal division yellow.
Mesothorax, black; the callous dot and a small dot on either side,
above the base of the intermediate legs, yellow. Metathorax, black,
with two yellow spots behind and a larger one, on either side, above
the base of the hind-legs. The first two spots are sometimes missing.

Abdomen, brilliant black above and bare, except at the base of the
first segment, which bristles with whitish hairs. All the segments have
a wavy transversal band, wider at the sides than in the middle and
nearer to the hinder edge as the segment is farther back. On the fifth
segment the yellow band touches the hinder edge. Anal segment, yellow,
black at the root, covered all over the dorsal surface with rusty-red
papillæ, forming a base for bristles. A row of similar bristle-bearing
protuberances occupies also the hinder edge of the fifth segment.
Underneath, the abdomen is brilliant black, with a triangular yellow
patch on either side of the four intermediary segments.

Black hips; thighs, yellow in front, black behind; yellow legs and
tarsi. Transparent wings.

In the male the chevron mark on the shield is narrower, or even
entirely absent, in which case the face is all yellow. The bands on the
abdomen are a very pale yellow, almost white. The sixth segment has a
band like those which come before, but shorter and often reduced to two
dots. The second segment has underneath it a longitudinal carina,
raised and spine-shaped at the back. Lastly, the anal segment carries
below it a rather thick angular projection. The rest is the same as in
the female.

This Wasp is very much like Bembex rostrata in size and in the
arrangement of the black and yellow. The chief differences lie in the
following characteristics: the shield of Bembex Julii forms a trihedral
angle, whereas it is rounded and convex in the other Bembex. It also
has at its base a broad, chevron-shaped black band, formed of two
rectangular patches joined together and powdered with a silvery down,
which is very brilliant in a suitable light. The upper surface of the
anal segment bristles with papillæ and reddish hairs, as does the
hinder edge of the fifth segment. Lastly, the mandibles are stained
black at the tips only, whereas the base also is black in Bembex
rostrata. Their habits are equally dissimilar. Bembex rostrata hunts
Gad-flies mainly; Bembex Julii never preys on big Flies but attacks
smaller ones of greatly varying species.

Jules’ Bembex is frequent in the sandy soil of Les Angles, round about
Avignon and on the hill at Orange.



D

AMMOPHILA JULII.—H. FAB.

Length, 16 to 22 millimetres. [59] Abdominal petiole consisting of the
first segment and half the second. Third cubital narrowed towards the
radial. Head, black, with silvery down on the face. Antennæ, black.
Thorax, black, with transverse stripes on its three segments, darker on
the prothorax and the mesothorax. Two patches on the sides and one
behind either side of the metathorax, covered with silvery down.
Abdomen, bare and shiny. First segment, black. Second segment, red in
the part narrowed into a petiole and in the widened part. Third
segment, all red. The others, a beautiful, metallic indigo-blue. Legs,
black, with silvery down on the hips. Wings, slightly reddish. Builds
her nest in October and stocks each cell with two medium-sized
caterpillars.

Is nearly related to Ammophila holosericea, being of the same size, but
differs markedly in the colour of her legs, which are all black, in her
head and thorax, which are much less hairy, and in the transverse
stripes on the three segments of the thorax.



I wish these three Wasps to bear the name of my son Jules, to whom I
dedicate them.

Dear Jules, snatched at such an early age from your passionate love of
flowers and insects, you were my fellow-worker; nothing escaped your
clear-sighted glance; I was to write this book for you, to whom its
stories gave such delight; and you yourself were to continue it one
day. Alas, you went to a happier home, knowing nothing of the book but
its first lines! May your name at least figure in it, borne by some of
those industrious and beautiful Wasps whom you loved so well!


J. H. F.

Orange, 3 April 1879.



NOTES


[1] Léon Dufour (1780–1865) was an army surgeon who served with
distinction in several campaigns and subsequently practised as a doctor
in the Landes. He attained great eminence as a naturalist. Cf. The Life
of the Spider, by J. Henri Fabre, translated by Alexander Teixeira de
Mattos, chap, i.—Translator’s Note.

[2] For the complete monograph, cf. Annales des sciences naturelles:
Series II., vol. xv.—Author’s Note.

[3] The 450 Buprestes unearthed belong to the following species:
Buprestis octoguttata; B. fasciata; B. pruni; B. tarda; B. biguttata;
B. micans; B. flavomaculata; B. chrysostigma; and B.
novemmaculata.—Author’s Note.

[4] Pierre André Latreille (1762–1833), a French naturalist who was one
of the founders of entomological science.—Translator’s Note.

[5] The Beetle known to Fabre as Sphenoptera geminata, Uliger, is now
considered identical with S. lineola, Herbst, which was known many
years earlier.—Translator’s Note.

[6] ·528 oz. av.—Translator’s Note.

[7] ·88 oz. av.—Translator’s Note.

[8] For a description of this species, which is new to entomology, see
the Appendix.—Author’s Note.

[9] Marie Jean Pierre Flourens (1794–1867), the celebrated French
physiologist, appointed perpetual secretary of the Academy of Science
in 1833 and a member of the French Academy.—Translator’s Note.

[10] François Magendie (1783–1855), professor of anatomy in the Collège
de France, noted for his experiments on the physiology of the
nerves.—Translator’s Note.

[11] Claude Bernard (1813–1878), another distinguished French
physiologist and perhaps the most famous representative of experimental
science in the nineteenth century.—Translator’s Note.

[12] Annales des sciences naturelles, Series III., vol. v.—Author’s
Note.

[13] For the Sacred Scarab, or Sacred Beetle, cf. Insect Life, by J. H.
Fabre, translated by the author of Mademoiselle Mori: chaps. i. and
ii.; and The Life and Love of the Insect, by J. Henri Fabre, translated
by Alexander Teixeira de Mattos: chaps, i. to iv.—Translator’s Note.

[14] For Philanthus Apivorus, the Bee-eating Wasp, cf. Social Life in
the Insect World, by J. H. Fabre, translated by Bernard Miall: chap.
xiii.—Translator’s Note.

[15] Cf. The Life and Love of the Insect: chap. xi.—Translator’s Note.

[16] Cf. The Life and Love of the Insect: chap. xii.—Translators Note.

[17] ·117 to ·156 inch.—Translator’s Note.

[18] A species of Green Grasshopper.—Translator’s Note.

[19] Nearly half an inch.—Translator’s Note.

[20] ·975 to 1·17 inch.—Translator’s Note.

[21] ·195 to ·234 inch.—Translator’s Note.

[22] 1·05 × ·35 inch.—Translator’s Note.

[23] Cf. Social Life in the Insect World: chaps. i. to iv.—Translator’s
Note.

[24] Cf. Social Life in the Insect World: chaps. v. to
vii.—Translator’s Note.

[25] The order of insects including Earwigs, Cockroaches, Mantes,
Crickets, Locusts and Grasshoppers.—Translator’s Note.

[26] Amédée Comte Lepeletier de Saint-Fargeau (1769–circa 1850), author
of an Histoire naturelle des insectes (1836–1846) and of the volume on
insects in the Encyclopédie méthodique. He was a younger brother of
Louis Michel and Félix Lepeletier de Saint-Fargeau, the members of the
Convention.—Translator’s Note.

[27] Jean Théodore Lacordaire (1801–1870), professor at the university
of Liège from 1835, author of Les Genera des coléoptères, in twelve
volumes, and of the Introduction à l’entomologie quoted above
(1837–1839).—Translator’s Note.

[28] Erasmus Darwin (1731–1802), the poet and naturalist, grandfather
of Charles Robert Darwin. The book from which the above passage is
quoted is Zoonomia, or, The Laws of Organic Life (1794–1796); but the
reader will note that the author withdraws these comments in a later
essay (cf. The Mason-bees, by J. Henri Fabre, translated by Alexander
Teixeira de Mattos: chap. vii.), where he explains that they are due to
a misquotation or mistranslation made by Lacordaire, who wrote ‘a
Sphex’ where Darwin, as his grandson pointed out to Fabre, had written
‘a Wasp,’ meaning the Common or Social Wasp. It was open to me to
suppress this part of the chapter; but, in that case, there would have
been so little left of the original and so small an excuse for the
title that I might as readily have suppressed the whole chapter, a
liberty which I did not feel justified in taking. Besides, the footnote
to the aforementioned chapter of The Mason-bees, which precedes the
present volume in the English edition, makes sufficient amends for any
injury done to the elder Darwin’s reputation here.—Translator’s Note.

[29]   ‘The busy bees, with a soft murmuring strain,
        Invite to gentle sleep the labouring swain.’—

                                Pastorals, i., Dryden’s translation.

[30] Cf. p. 43 n. Flourens’ Expériences sur le système nerveux were
first published in 1825.—Translator’s Note.

[31] ·039 inch.—Translator’s Note.

[32] The caterpillars of the Geometræ, or Geometrid Moths, are called
also Inchworms, Spanworms and Surveyors.—Translator’s Note.

[33] Cf. The Life of the Fly, by J. Henri Fabre, translated by
Alexander Teixeira de Mattos: chap. ix.—Translator’s Note.

[34] About ·08 inch.—Translator’s Note.

[35] For a description of this new species, see the Appendix to the
present volume.—Author’s Note.

[36] Or Flesh-fly. Cf. The Life of the Fly: chap. x.—Translator’s Note.

[37] The Bluebottle.—Translator’s Note.

[38] The Common House-fly.—Translator’s Note.

[39] Cf. The Life of the Fly: chaps. ii. and iv.—Translator’s Note.

[40] For other essays on the homing of insects, cf. The Mason-bees:
chaps. ii. to vi.—Translator’s Note.

[41] ·061 cubic inch.—Translator’s Note.

[42] 61 cubic inches.—Translator’s Note.

[43] The piece of waste ground on which the author used to study his
insects in their natural state. Cf. The Life of the Fly: chap.
i.—Translator’s Note.

[44] Gun-flints.—Author’s Note.

[45] The local expression.—Author’s Note.

[46] Burying-beetles.—Translator’s Note.

[47] Carrion-beetles.—Translator’s Note.

[48] Mimic-beetles.—Translator’s Note.

[49] Bacon-beetles.—Translator’s Note.

[50] The Horseshoe Bat.—Translator’s Note.

[51] Lazaro Spallanzani (1729–1799), the great Italian
naturalist.—Translator’s Note.

[52]   ‘This night, at least, with me forget your care;
        Chestnuts and curds and cream shall be your fare
        The carpet-ground shall be with leaves o’erspread
        And boughs shall weave a covering for your head.’—

                            Pastorals, book i., Dryden’s translation.

[53] Louis Racine (1692–1763), son of Jean Racine.—Translator’s Note.

[54]            ... and even in the mire,
        The insect, of its worth assured, once and again
        Ventures to challenge us to make good our disdain.

[55] L. Couty, in the Revue scientifique, 6 August 1881.—Author’s Note.

[56] ⅝ to ¾ inch.—Translator’s Note.

[57] ¼ to ⅓ inch.—Translator’s Note.

[58] ¾ to ⅞ inch.—Translator’s Note.

[59] ·62 to ·86 inch.—Translator’s Note.





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