Title: The Life of the Caterpillar
Author: Fabre, Jean-Henri
Language: English
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                            THE LIFE OF THE
                              CATERPILLAR


                                   BY
                             J. HENRI FABRE

                             TRANSLATED BY

                      Alexander Teixeira de Mattos
               FELLOW OF THE ZOOLOGICAL SOCIETY OF LONDON


                                NEW YORK
                         DODD, MEAD AND COMPANY
                                  1916



CONTENTS


                                                                PAGE
    TRANSLATOR’S NOTE                                              5

    CHAPTER
    I       THE PINE PROCESSIONARY: LAYING THE EGGS                9
    II      THE PINE PROCESSIONARY: THE NEST; THE COMMUNITY       27
    III     THE PINE PROCESSIONARY: THE PROCESSION                56
    IV      THE PINE PROCESSIONARY: METEOROLOGY                   90
    V       THE PINE PROCESSIONARY: THE MOTH                     111
    VI      THE PINE PROCESSIONARY: THE STINGING POWER           128
    VII     THE ARBUTUS CATERPILLAR                              150
    VIII    AN INSECT VIRUS                                      161
    IX      THE PSYCHES: THE LAYING                              186
    X       THE PSYCHES: THE CASES                               217
    XI      THE GREAT PEACOCK                                    246
    XII     THE BANDED MONK                                      279
    XIII    THE SENSE OF SMELL                                   300
    XIV     THE CABBAGE-CATERPILLAR                              331



TRANSLATOR’S NOTE


This, the sixth volume of the Collected Edition of Fabre’s
Entomological Works in English, is the first that I am preparing for
publication since the author’s death, on the 11th of October, 1915, at
an exceedingly advanced age. It contains all the essays, fourteen in
number, which he wrote on Butterflies and Moths, or their caterpillars.

Three of these, the chapters entitled The Great Peacock, The Banded
Monk and The Sense of Smell, are included under the titles of The Great
Peacock, The Oak Eggar and A Truffle-hunter: the Bolboceras Gallicus in
a volume of miscellaneous extracts from the Souvenirs entomologiques
translated by Mr. Bernard Miall and published by the Century Company.
The volume in question is named Social Life in the Insect World; and I
strongly recommend it to the reader, if only because of the excellent
photographs from nature with which it is illustrated.

Chapter III. of the present volume, The Pine Processionary: the
Procession, has appeared in the Fortnightly Review; and Chapter XIV.,
The Cabbage Caterpillar, the last essay but one from the author’s pen,
written, I believe, within two or three years of his death, was first
printed in the Century Magazine, some time before its publication in
the original. It does not form part of the Souvenirs entomologiques.
The remaining essays are new in their English guise.

Once more I wish to record my gratitude to Miss Frances Rodwell for the
faithful assistance which she has lent me in the preparation of this
volume, as in that of all the earlier volumes of the series.


Alexander Teixeira de Mattos.

Chelsea, 1916.



CHAPTER I

THE PINE PROCESSIONARY: THE EGGS AND THE HATCHING


This caterpillar has already had his story told by Réaumur, [1] but it
was a story marked by gaps. These were inevitable in the conditions
under which the great man worked, for he had to receive all his
materials by barge from the distant Bordeaux Landes. The transplanted
insect could not be expected to furnish its biographer with other than
fragmentary evidence, very weak in those biological details which form
the principal charm of entomology. To study the habits of insects one
must observe them long and closely on their native heath, so to speak,
in the place where their instincts have full and natural play.

With caterpillars foreign to the Paris climate and brought from the
other end of France, Réaumur therefore ran the risk of missing many
most interesting facts. This is what actually happened, just as it did
on a later occasion in the case of another alien, the Cicada. [2]
Nevertheless, the information which he was able to extract from a few
nests sent to him from the Landes is of the highest value.

Better served than he by circumstances, I will take up afresh the story
of the Processionary Caterpillar of the Pine. If the subject does not
come up to my hopes, it will certainly not be for lack of materials. In
my harmas [3] laboratory, now stocked with a few trees in addition to
its bushes, stand some vigorous fir-trees, the Aleppo pine and the
black Austrian pine, a substitute for that of the Landes. Every year
the caterpillar takes possession of them and spins his great purses in
their branches. In the interest of the leaves, which are horribly
ravaged, as though there had been a fire, I am obliged each winter to
make a strict survey and to extirpate the nests with a long forked
batten.

You voracious little creatures, if I let you have your way, I should
soon be robbed of the murmur of my once so leafy pines! Today I will
seek compensation for all the trouble I have taken. Let us make a
compact. You have a story to tell. Tell it me; and for a year, for two
years or longer, until I know more or less all about it, I shall leave
you undisturbed, even at the cost of lamentable suffering to the pines.

Having concluded the treaty and left the caterpillars in peace, I soon
have abundant material for my observations. In return for my indulgence
I get some thirty nests within a few steps of my door. If the
collection were not large enough, the pine-trees in the neighbourhood
would supply me with any necessary additions. But I have a preference
and a decided preference for the population of my own enclosure, whose
nocturnal habits are much easier to observe by lantern-light. With such
treasures daily before my eyes, at any time that I wish and under
natural conditions, I cannot fail to see the Processionary’s story
unfolded at full length. Let us try.

And first of all the egg, which Réaumur did not see. In the first
fortnight of August, let us inspect the lower branches of the pines, on
a level with our eyes. If we pay the least attention, we soon discover,
here and there, on the foliage, certain little whitish cylinders
spotting the dark green. These are the Bombyx’ eggs: each cylinder is
the cluster laid by one mother.

The pine-needles are grouped in twos. Each pair is wrapped at its base
in a cylindrical muff which measures about an inch long by a fifth or
sixth of an inch wide. This muff, which has a silky appearance and is
white slightly tinted with russet, is covered with scales that overlap
after the manner of the tiles on a roof; and yet their arrangement,
though fairly regular, is by no means geometrical. The general aspect
is more or less that of an immature walnut-catkin.

The scales are almost oval in form, semitransparent and white, with a
touch of brown at the base and of russet at the tip. They are free at
the lower end, which tapers slightly, but firmly fixed at the upper
end, which is wider and blunter. You cannot detach them either by
blowing on them or by rubbing them repeatedly with a hair-pencil. They
stand up, like a fleece stroked the wrong way, if the sheath is rubbed
gently upwards, and retain this bristling position indefinitely; they
resume their original arrangement when the friction is in the opposite
direction. At the same time, they are as soft as velvet to the touch.
Carefully laid one upon the other, they form a roof that protects the
eggs. It is impossible for a drop of rain or dew to penetrate under
this shelter of soft tiles.

The origin of this defensive covering is self-evident: the mother has
stripped a part of her body to protect her eggs. Like the Eider-duck,
she has made a warm overcoat for them out of her own down. Réaumur had
already suspected as much from a very curious peculiarity of the Moth.
Let me quote the passage:


   “The females,” he says, “have a shiny patch on the upper part of
    their body, near the hind-quarters. The shape and gloss of this
    disk attracted my attention the first time that I saw it. I was
    holding a pin, with which I touched it, to examine its structure.
    The contact of the pin produced a little spectacle that surprised
    me: I saw a cloud of tiny spangles at once detach themselves. These
    spangles scattered in every direction: some seemed to be shot into
    the air, others to the sides; but the greater part of the cloud
    fell softly to the ground.

   “Each of those bodies which I am calling spangles is an extremely
    slender lamina, bearing some resemblance to the atoms of dust on
    the Moths’ wings, but of course much bigger.... The disk that is so
    noticeable on the hind-quarters of these Moths is therefore a
    heap—and an enormous heap—of these scales.... The females seem to
    use them to wrap their eggs in; but the Moths of the Pine
    Caterpillar refused to lay while in my charge and consequently did
    not enlighten me as to whether they use the scales to cover their
    eggs or as to what they are doing with all those scales gathered
    round their hinder part, which were not given them and placed in
    that position to serve no purpose.”


You were right, my learned master: that dense and regular crop of
spangles did not grow on the Moth’s tail for nothing. Is there anything
that has no object? You did not think so; I do not think so either.
Everything has its reason for existing. Yes, you were well-inspired
when you foresaw that the cloud of scales which flew out under the
point of your pin must serve to protect the eggs.

I remove the scaly fleece with my pincers and, as I expected, the eggs
appear, looking like little white-enamel beads. Clustering closely
together, they make nine longitudinal rows. In one of these rows I
count thirty-five eggs. As the nine rows are very nearly alike, the
contents of the cylinder amount in all to about three hundred eggs, a
respectable family for one mother!

The eggs of one row or file alternate exactly with those in the two
adjoining files, so as to leave no empty spaces. They suggest a piece
of bead-work produced with exquisite dexterity by patient fingers. It
would be more correct still to compare them with a cob of Indian corn,
with its neat rows of seeds, but a greatly reduced cob, the tininess of
whose dimensions makes its mathematical precision all the more
remarkable. The grains of the Moth’s spike have a slight tendency to be
hexagonal, because of their mutual pressure; they are stuck close
together, so much so that they cannot be separated. If force is used,
the layer comes off the leaf in fragments, in small cakes always
consisting of several eggs apiece. The beads laid are therefore
fastened together by a glutinous varnish; and it is on this varnish
that the broad base of the defensive scales is fixed.

It would be interesting, if a favourable opportunity occurred, to see
how the mother achieves that beautifully regular arrangement of the
eggs and also how, as soon as she has laid one, all sticky with
varnish, she makes a roof for it with a few scales removed one by one
from her hind-quarters. For the moment, the very structure of the
finished work tells us the course of the procedure. It is evident that
the eggs are not laid in longitudinal files, but in circular rows, in
rings, which lie one above the other, alternating their grains. The
laying begins at the bottom, near the lower end of the double
pine-leaf; it finishes at the top. The first eggs in order of date are
those of the bottom ring; the last are those of the top ring. The
arrangement of the scales, all in a longitudinal direction and attached
by the end facing the top of the leaf, makes any other method of
progression inadmissible.

Let us consider in the light of reflection the elegant edifice now
before our eyes. Young or old, cultured or ignorant, we shall all, on
seeing the Bombyx’ pretty little spike, exclaim:

“How handsome!”

And what will strike us most will be not the beautiful enamel pearls,
but the way in which they are put together with such geometrical
regularity. Whence we can draw a great moral, to wit, that an exquisite
order governs the work of a creature without consciousness, one of the
humblest of the humble. A paltry Moth follows the harmonious laws of
order.

If Micromégas [4] took it into his head to leave Sirius once more and
visit our planet, would he find anything to admire among us? Voltaire
shows him to us using one of the diamonds of his necklace as a
magnifying-glass in order to obtain some sort of view of the
three-master which has run aground on his thumb-nail. He enters into
conversation with the crew. A nail-paring, curved like a horn,
encompasses the ship and serves as a speaking-trumpet; a tooth-pick,
which touches the vessel with its tapering end and the lips of the
giant, some thousand fathoms above, with the other, serves as a
telephone. The outcome of the famous dialogue is that, if we would form
a sound judgment of things and see them under fresh aspects, there is
nothing like changing one’s planet.

The probability then is that the Sirian would have had a rather poor
notion of our artistic beauties. To him our masterpieces of statuary,
even though sprung from the chisel of a Phidias, would be mere dolls of
marble or bronze, hardly more worthy of interest than the children’s
rubber dolls are to us; our landscape-paintings would be regarded as
dishes of spinach smelling unpleasantly of oil; our opera-scores would
be described as very expensive noises.

These things, belonging to the domain of the senses, possess a relative
æsthetic value, subordinated to the organism that judges them.
Certainly the Venus of Melos and the Apollo Belvedere are superb works;
but even so it takes a special eye to appreciate them. Micromégas, if
he saw them, would be full of pity for the leanness of human forms. To
him the beautiful calls for something other than our sorry, frog-like
anatomy.

Show him, on the other hand, that sort of abortive windmill by means of
which Pythagoras, echoing the wise men of Egypt, teaches us the
fundamental properties of the right-angled triangle. Should the good
giant, contrary to our expectation, happen not to know about it,
explain to him what the windmill means. Once the light has entered his
mind, he will find, just as we do, that there is beauty there, real
beauty, not certainly in that horrible hieroglyphic, the figure, but in
the unchangeable relation between the lengths of the three sides; he
will admire as much as we do geometry the eternal balancer of space.

There is, therefore, a severe beauty, belonging to the domain of
reason, the same in every world, the same under every sun, whether the
suns be single or many, white or red, blue or yellow. This universal
beauty is order. Everything is done by weight and measure, a great
statement whose truth breaks upon us all the more vividly as we probe
more deeply into the mystery of things.

Is this order, upon which the equilibrium of the universe is based, the
predestined result of a blind mechanism? Does it enter into the plans
of an Eternal Geometer, as Plato had it? Is it the ideal of a supreme
lover of beauty, which would explain everything?

Why all this regularity in the curve of the petals of a flower, why all
this elegance in the chasings on a Beetle’s wing-cases? Is that
infinite grace, even in the tiniest details, compatible with the
brutality of uncontrolled forces? One might as well attribute the
artist’s exquisite medallion to the steam-hammer which makes the slag
sweat in the melting.

These are very lofty thoughts concerning a miserable cylinder which
will bear a crop of caterpillars. It cannot be helped. The moment one
tries to dig out the least detail of things, up starts a why which
scientific investigation is unable to answer. The riddle of the world
has certainly its explanation otherwhere than in the little truths of
our laboratories. But let us leave Micromégas to philosophize and
return to the commonplaces of observation.

The Pine Bombyx has rivals in the art of gracefully grouping her
egg-beads. Among their number is the Neustrian Bombyx, whose
caterpillar is known by the name of “Livery,” because of his costume.
Her eggs are assembled in bracelets around little branches varying
greatly in nature, apple- and pear-branches chiefly. Any one seeing
this elegant work for the first time would be ready to attribute it to
the fingers of a skilled stringer of beads. My small son Paul opens
eyes wide with surprise and utters an astonished “Oh!” each time that
he comes upon the dear little bracelet. The beauty of order forces
itself upon his dawning attention.

Though not so long and marked above all by the absence of any wrapper,
the ring of the Neustrian Bombyx reminds one of the other’s cylinder,
stripped of its scaly covering. It would be easy to multiply these
instances of elegant grouping, contrived now in one way, now in
another, but always with consummate art. It would take up too much
time, however. Let us keep to the Pine Bombyx.

The hatching takes place in September, a little earlier in one case, a
little later in another. So that I may easily watch the new-born
caterpillars in their first labours, I have placed a few egg-laden
branches in the window of my study. They are standing in a glass of
water which will keep them properly fresh for some time.

The little caterpillars leave the egg in the morning, at about eight
o’clock. If I just lift the scales of the cylinder in process of
hatching, I see black heads appear, which nibble and burst and push
back the torn ceilings. The tiny creatures emerge slowly, some here and
some there, all over the surface.

After the hatching, the scaly cylinder is as regular and as fresh in
appearance as if it were still inhabited. We do not perceive that it is
deserted until we raise the spangles. The eggs, still arranged in
regular rows, are now so many yawning goblets of a slightly translucent
white; they lack the cap-shaped lid, which has been rent and destroyed
by the new-born grubs.

The puny creatures measure a millimetre [5] at most in length. Devoid
as yet of the bright red that will soon be their adornment, they are
pale-yellow, bristling with hairs, some shortish and black, others
rather longer and white. The head, of a glossy black, is big in
proportion. Its diameter is twice that of the body. This exaggerated
size of the head implies a corresponding strength of jaw, capable of
attacking tough food from the start. A huge head, stoutly clad in horn,
is the predominant feature of the budding caterpillar.

These macrocephalous ones are, as we see, well-armed against the
hardness of the pine-needles, so well-armed in fact that the meal
begins almost immediately. After roaming for a few moments at random
among the scales of the common cradle, most of the young caterpillars
make for the double leaf that served as an axis for the native cylinder
and spread themselves over it at length. Others go to the adjacent
leaves. Here as well as there they fall to; and the gnawed leaf is
hollowed into faint and very narrow grooves, bounded by the veins,
which are left intact.

From time to time, three or four who have eaten their fill fall into
line and walk in step, but soon separate, each going his own way. This
is practice for the coming processions. If I disturb them ever so
little, they sway the front half of their bodies and wag their heads
with a jerky movement similar to the action of an intermittent spring.

But the sun reaches the corner of the window where the careful rearing
is in progress. Then, sufficiently refreshed, the little family
retreats to its native soil, the base of the double leaf, gathers into
an irregular group and begins to spin. Its work is a gauze globule of
extreme delicacy, supported on some of the neighbouring leaves. Under
this tent, a very wide-meshed net, a siesta is taken during the hottest
and brightest part of the day. In the afternoon, when the sun has gone
from the window, the flock leaves its shelter, disperses around,
sometimes forming a little procession within a radius of an inch, and
starts browsing again.

Thus the very moment of hatching proclaims talents which age will
develop without adding to their number. In less than an hour from the
bursting of the egg, the caterpillar is both a processionary and a
spinner. He also flees the light when taking refreshment. We shall soon
find him visiting his grazing-grounds only at night.

The spinner is very feeble, but so active that in twenty-four hours the
silken globe attains the bulk of a hazel-nut and in a couple of weeks
that of an apple. Nevertheless, it is not the nucleus of the great
establishment in which the winter is to be spent. It is a provisional
shelter, very light and inexpensive in materials. The mildness of the
season makes anything else unnecessary. The young caterpillars freely
gnaw the logs, the poles between which the threads are stretched, that
is to say, the leaves contained within the silken tent. Their house
supplies them at the same time with board and lodging. This excellent
arrangement saves them from having to go out, a dangerous proceeding at
their age. For these puny ones, the hammock is also the larder.

Nibbled down to their veins, the supporting leaves wither and easily
come unfastened from the branches; and the silken globe becomes a hovel
that crumbles with the first gust of wind. The family then moves on and
goes elsewhere to erect a new tent, lasting no longer than the first.
Even so does the Arab move on, as the pastures around his camel-hide
dwelling become exhausted. These temporary establishments are renewed
several times over, always at greater heights than the last, so much so
that the tribe, which was hatched on the lower branches trailing on the
ground, gradually reaches the higher boughs and sometimes the very
summit of the pine-tree.

In a few weeks’ time, a first moult replaces the humble fleece of the
start, which is pale-coloured, shaggy and ugly, by another which lacks
neither richness nor elegance. On the dorsal surface, the various
segments, excepting the first three, are adorned with a mosaic of six
little bare patches, of a bright red, which stand out a little above
the dark background of the skin. Two, the largest, are in front, two
behind and one, almost dot-shaped, on either side of the quadrilateral.
The whole is surrounded by a palisade of scarlet bristles, divergent
and lying almost flat. The other hairs, those of the belly and sides,
are longer and whitish.

In the centre of this crimson marquetry stand two clusters of very
short bristles, gathered into flattened tufts which gleam in the sun
like specks of gold. The length of the caterpillar is now about two
centimetres [6] and his width three or four millimetres. [7] Such is
the costume of middle age, which, like the earlier one, was unknown to
Réaumur.



CHAPTER II

THE PINE PROCESSIONARY: THE NEST; THE COMMUNITY


November arrives, however, bringing cold weather; the time has come to
build the stout winter tabernacle. High up in the pine the tip of a
bough is chosen, with suitably close-packed and convergent leaves. The
spinners surround it with a spreading network, which bends the adjacent
leaves a little nearer and ends by incorporating them into the fabric.
In this way they obtain an enclosure half silk, half leaves, capable of
withstanding the inclemencies of the weather.

Early in December the work has increased to the size of a man’s two
fists or more. In its ultimate perfection, it attains a volume of
nearly half a gallon by the end of winter.

It is roughly egg-shaped, tapering to a certain length below and
extended into a sheath which envelops the supporting branch. The origin
of this silky extension is as follows: every evening between seven and
nine o’clock, weather permitting, the caterpillars leave the nest and
go down the bare part of the bough which forms the pole of the tent.
The road is broad, for this axis is sometimes as wide as the neck of a
claret-bottle. The descent is accomplished without any attempt at order
and always slowly, so much so that the first caterpillars to come out
have not yet dispersed before they are caught up by the others. The
branch is thus covered by a continuous bark of caterpillars, made up of
the whole community, which gradually divides into squads and disperses
to this side and that on the nearest branches to crop their leaves. Now
not one of the caterpillars moves a step without working his spinneret.
Therefore the broad downward path, which on the way back will be the
ascending path, is covered, as the result of constant traffic, with a
multitude of threads forming an unbroken sheath.

It is obvious that this sheath, in which each caterpillar, passing
backwards and forwards on his nocturnal rambles, leaves a double
thread, is not an indicator laid down with the sole object of
simplifying the journey back to the nest: a mere ribbon would be enough
for that. Its use might well be to strengthen the edifice, to give it
deeper foundations and to join it by a multitude of cables to the
steady branch.

The whole thing thus consists, above, of the home distended into an
ovoid and, below, of the stalk, the sheath surrounding the support and
adding its resistance to that of the numerous other fastenings.

Each nest that has not yet had its shape altered by the prolonged
residence of the caterpillars shows in the centre a bulky, milk-white
shell, with around it a wrapper of diaphanous gauze. The central mass,
formed of thickly-woven threads, has for a wall a thick quilt into
which are absorbed, as supports, numbers of leaves, green and intact.
The thickness of this wall may be anything up to three-quarters of an
inch.

At the top of the dome are round openings, varying greatly in number
and distribution, as wide across as an ordinary lead-pencil. These are
the doors of the house, through which the caterpillars go in and out.
All around the shell are projecting leaves, which the insects’ teeth
have respected. From the tip of each leaf there radiate, in graceful,
undulating curves, threads which, loosely interlaced, form a light
tent, a spacious verandah of careful workmanship, especially in the
upper part. Here we find a broad terrace on which, in the daytime, the
caterpillars come and doze in the sun, heaped one upon the other, with
rounded backs. The network stretching overhead does duty as an awning:
it moderates the heat of the sun’s rays; it also saves the sleepers
from a fall when the bough rocks in the wind.

Let us take our scissors and rip open the nest from end to end
longitudinally. A wide window opens and allows us to see the
arrangement of the inside. The first thing to strike us is that the
leaves contained in the enclosure are intact and quite sound. The young
caterpillars in their temporary establishments gnaw the leaves within
the silken wrapper to death; they thus have their larder stocked for a
few days without having to quit their shelter in bad weather, a
condition made necessary by their weakness. When they grow stronger and
start working on their winter home, they are very careful not to touch
the leaves. Why these new scruples?

The reason is evident. If bruised, those leaves, the framework of the
house, would very soon wither and then be blown off with the first
breath of wind. The silken purse, torn from its base, would collapse.
On the other hand, if the leaves are respected, they remain vigorous
and furnish a stout support against the assaults of winter. A solid
fastening is superfluous for the summer tent, which lasts but a day; it
is indispensable to the permanent shelter which will have to bear the
burden of heavy snows and the buffeting of icy winds. Fully alive to
these perils, the spinner of the pine-tree considers himself bound,
however importunate his hunger, not to saw through the rafters of his
house.

Inside the nest, therefore, opened by my scissors I see a thick arcade
of green leaves, more or less closely wrapped in a silky sheath whence
dangle shreds of cast skin and strings of dried droppings. In short,
this interior is an extremely unpleasant place, a rag-shop and a
sewage-farm in one, and corresponds in no way with the imposing
exterior. All around is a solid wall of quilting and of closely-woven
leaves. There are no chambers, no compartments marked off by
partition-walls. It is a single room, turned into a labyrinth by the
colonnade of green leaves placed in rows one above the other throughout
the oval hall. Here the caterpillars stay when resting, gathered on the
columns, heaped in confused masses.

When we remove the hopeless tangle at the top, we see the light
filtering in at certain points of the roof. These luminous points
correspond with the openings that communicate with the outer air. The
network that forms a wrapper to the nest has no special exits. To pass
through it in either direction, the caterpillars have only to push the
sparse threads aside slightly. The inner wall, a compact rampart, has
its doors; the flimsy outer veil has none.

It is in the morning, at about ten o’clock, that the caterpillars leave
their night-apartment and come to take the sun on their terrace, under
the awning which the points of the leaves hold up at a distance. They
spend the whole day there dozing. Motionless, heaped together, they
steep themselves deliciously in warmth and from time to time betray
their bliss by nodding and wagging their heads. At six or seven
o’clock, when it grows dark, the sleepers awake, bestir themselves,
separate and go their several ways over the surface of the nest.

We now behold an indeed delightful spectacle. Bright-red stripes
meander in every direction over the white sheet of silk. One goes up,
another comes down, a third moves aslant; others form a short
procession. And, as they solemnly walk about in a splendid disorder,
each glues to the ground which it covers the thread that constantly
hangs from its lip.

Thus is the thickness of the shelter increased by a fine layer added
immediately above the previous structure; thus is the dwelling
strengthened by fresh supports. The adjoining green leaves are taken
into the network and absorbed in the building. If the tiniest bit of
them remains free, curves radiate from that point, increasing the size
of the veil and fastening it at a greater distance. Every evening,
therefore, for an hour or two, great animation reigns on the surface of
the nest, if the weather permits; and the work of consolidating and
thickening the structure is carried on with indefatigable zeal.

Do they foresee the future, these wary ones who take such precautions
against the rigours of winter? Obviously not. Their few months’
experience—if indeed experience can be mentioned in connection with a
caterpillar—tells them of savoury bellyfuls of green stuff, of gentle
slumbers in the sun on the terrace of the nest; but nothing hitherto
has made them acquainted with cold, steady rain, with frost, snow and
furious blasts of wind. And these creatures, knowing naught of winter’s
woes, take the same precautions as if they were thoroughly aware of all
that the inclement season holds in store for them. They work away at
their house with an ardour that seems to say:

“Oh, how nice and warm we shall be in our beds here, nestling one
against the other, when the pine-tree swings aloft its frosted
candelabra! Let us work with a will! Laboremus!”

Yes, caterpillars, my friends, let us work with a will, great and
small, men and grubs alike, so that we may fall asleep peacefully; you
with the torpor that makes way for your transformation into Moths, we
with that last sleep which breaks off life only to renew it. Laboremus!

Anxious to watch my caterpillars’ habits in detail, without having to
sally forth by lantern-light, often in bad weather, to see what happens
in the pine-trees at the end of the enclosure, I have installed
half-a-dozen nests in a greenhouse, a modest, glazed shelter which,
though hardly any warmer than the air outside, at least affords
protection from the wind and rain. Fixed in the sand, at a height of
about eighteen inches, by the base of the bough that serves as both an
axis and a framework, each nest receives for rations a bundle of little
pine-branches, which are renewed as soon as they are consumed. I take
my lantern every evening and pay my boarders a visit. This is the way
in which most of my facts are obtained.

After the day’s work comes the evening meal. The caterpillars descend
from the nest, adding a few more threads to the silvery sheath of the
support, and reach the posy of fresh green stuff which is lying quite
near. It is a magnificent sight to see the red-coated band lined up in
twos and threes on each needle and in ranks so closely formed that the
green sprigs of the bunch bend under the load.

The diners, all motionless, all poking their heads forward, nibble in
silence, placidly. Their broad black foreheads gleam in the rays of the
lantern. A shower of granules drops on the sand below. These are the
residues of easy-going stomachs, only too ready to digest their food.
By to-morrow morning the soil will have disappeared under a greenish
layer of this intestinal hail. Yes, indeed, it is a sight to see, one
far more stimulating than that of the Silk-worms’ mess-room. Young and
old, we are all so much interested in it that our evenings almost
invariably end in a visit to the greenhouse caterpillars.

The meal is prolonged far into the night. Satisfied at last, some
sooner, some later, they go back to the nest, where for a little
longer, feeling their silk-glands filled, they continue spinning on the
surface. These hard workers would scruple to cross the white carpet
without contributing a few threads. It is getting on for one or even
two o’clock in the morning when the last of the band goes indoors.

My duty as a foster-father is daily to renew the bunch of sprigs, which
are shorn to the last leaf; on the other hand, my duty as an historian
is to enquire to what extent the diet can be varied. The district
supplies me with Processionaries on the Scotch pine, the maritime pine
and the Aleppo pine indifferently, but never on the other Coniferæ. Yet
one would think that any resin-scented leaf ought to suit. So says
chemical analysis.

We must mistrust the chemist’s retort when it pokes its nose into the
kitchen. It may succeed in making butter out of tallow-candles and
brandy out of potatoes; but, when it tells us that the products are
identical, we shall do well to refuse these abominations. Science,
astonishingly rich as it is in poison, will never provide us with
anything fit to eat, because, though the raw substance falls to a large
extent within its domain, that same substance escapes its methods the
moment that it is wanted organized, divided and subdivided indefinitely
by the process of life, as needed by the stomach, whose requirements
are not to be met by measured doses of our reagents. The raw material
of cell and fibre may perhaps be artificially obtained, some day; cell
and fibre themselves, never. There’s the rub with your chemical
feeding.

The caterpillars loudly proclaim the insurmountable difficulty of the
problem. Relying on my chemical data, I offer them the different
substitutes for the pine growing in my enclosure: the spruce, the yew,
the thuja, the juniper, the cypress. What! Am I asking them, Pine
Caterpillars, to bite into that? They will take good care not to,
despite the tempting resinous smell! They would die of hunger rather
than touch it! One conifer and one only is excepted: the cedar. My
charges browse upon its leaves with no appreciable repugnance. Why the
cedar and not the others? I do not know. The caterpillar’s stomach,
fastidious as our own, has its secrets.

Let us pass to other tests. I have just slit open longitudinally a nest
whose internal structure I want to explore. Owing to the natural
shrinkage of the split swan’s-down, the cleft reaches two fingers’
breadth in the centre and tapers at the top and bottom. What will the
spinners do in the presence of such a disaster? The operation is
performed by day, while the caterpillars are slumbering in heaps upon
the dome. As the living-room is deserted at this time, I can cut boldly
with the scissors without risk of damaging any part of the population.

My ravages do not wake the sleepers: all day long not one appears upon
the breach. This indifference looks as though it were due to the fact
that the danger is not yet known. Things will be different to-night,
when the busy work begins again. However dull they may be, the
caterpillars will certainly notice that huge window which freely admits
the deadly draughts of winter; and, possessing any amount of padding,
they will crowd round the dangerous gap and stop it up in a trice. Thus
do we argue, forgetting the animal’s intellectual darkness.

What really happens is that, when night falls, the indifference of the
caterpillars remains as great as ever. The breach in the tent provokes
not a sign of excitement. They move to and fro on the surface of the
nest; they work, they spin as usual. There is no change, absolutely
none, in their behaviour. When the road covered chances to bring some
of them to the brink of the ravine, we see no alacrity on their part,
no sign of anxiety, no attempt to close up the two edges of the slit.
They simply strive to accomplish the difficult crossing and to continue
their stroll as though they were walking on a perfect web. And they
manage it somehow or other, by fixing the thread as far as the length
of their body permits.

Having once crossed the gulf, they pursue their way imperturbably,
without stopping any more at the breach. Others come upon the scene
and, using the threads already laid as foot-bridges, pass over the rent
and walk on, leaving their own thread as they go. Thus the first
night’s work results in the laying over the cleft of a filmy gauze,
hardly perceptible, but just sufficient for the traffic of the colony.
The same thing is repeated on the nights that follow; and the crevice
ends by being closed with a scanty sort of Spider’s web. And that is
all.

There is no improvement by the end of the winter. The window made by my
scissors is still wide open, though thinly veiled; its black spindle
shape shows from the top of the nest to the bottom. There is no darn in
the split texture, no piece of swan’s-down let in between the two edges
to restore the roof to its original state. If the accident had happened
in the open air and not under glass, the foolish spinners would
probably have died of cold in their cracked house.

Twice renewed with the same results, this test proves that the Pine
Caterpillars are not alive to the danger of their split dwelling.
Expert spinners though they be, they seem as unconscious of the ruin of
their work as the spools in a factory are of a broken thread. They
could easily make good the damage by stopping up the breach with the
silk that is lavished elsewhere without urgent need; they could weave
upon it a material as thick and solid as the rest of the walls. But no,
they placidly continue their habitual task; they spin as they spun
yesterday and as they will spin to-morrow, strengthening the parts that
are already strong, thickening what is already thick enough; and not
one thinks of stopping the disastrous gap. To let a piece into that
hole would mean weaving the tent all over again from the beginning; and
no insect, however industrious, goes back to what it has already done.

I have often called attention to this feature in animal psychology;
notably I have described the ineptitude of the caterpillar of the Great
Peacock Moth. [8] When the experimenter lops the top off the
complicated eel-trap which forms the pointed end of the cocoon, this
caterpillar spends the silk remaining to him in work of secondary
importance, instead of making good the series of cones, each fitting
into the other, which are so essential to the hermit’s protection. He
continues his normal task imperturbably, as though nothing out of the
way had taken place. Even so does the spinner in the pine-tree act with
his burst tent.

Your foster-parent must perpetrate yet another piece of mischief, O my
Processionary; but this time it shall be to your advantage! It does not
take me long to perceive that the nests intended to last through the
winter often contain a population much greater than that of the
temporary shelters woven by the very young caterpillars. I also notice
that, when they have attained their ultimate dimensions, these nests
differ very considerably in size. The largest of them are equal to five
or six of the smallest. What is the cause of these variations?

Certainly, if all the eggs turned out well, the scaly cylinder
containing the laying of a single mother would be enough to fill a
splendid purse: there are three hundred enamelled beads here for
hatching. But in families which swarm unduly an enormous waste always
takes places and restores the balance of things; if the called are
legion, the chosen are a well thinned-out troop, as is proved by the
Cicada, the Praying Mantis [9] and the Cricket.

The Pine Processionary, another crucible of organic matter of which
various devourers take advantage, is also reduced in numbers
immediately after the hatching. The delicate mouthful has shrunk to a
few dozens of survivors around the light globular network in which the
family passes the sunny autumn days. Soon they will have to be thinking
of the stoutly-built winter tent. At such a time, it would be a boon if
they could be many, for from union springs strength.

I suspect an easy method of fusion among a few families. To serve them
as a guide in their peregrinations about the tree, the caterpillars
have their silk ribbon, which they follow on their return, after
describing a bend. They may also miss it and strike another, one
differing in no respect from their own. This new ribbon marks the way
to some nest situated in the neighbourhood. The strayed caterpillars,
failing to distinguish it from their own ribbon, follow it
conscientiously and in this manner end by reaching a strange dwelling.
Suppose them to be peacefully received: what will happen?

Once fused, the several groups assembled by the accident of the path
will form a powerful city, fitted to produce great works; the concerted
weaklings will give rise to a strong, united body. This would explain
the thickly-populated, bulky nests situated so near to others that have
remained puny. The former would be the work of a syndicate
incorporating the interests of spinners collected from different parts;
the latter would belong to families left in isolation by the luck of
the road.

It remains to be seen whether the chance-comers, guided by a strange
ribbon, meet with a good reception in the new abode. The experiment is
easily made upon the nests in the greenhouse. In the evening, at the
hours devoted to grazing, I remove with a pruning-shears the different
little branches covered with the population of one nest and lay them on
the provisions of the neighbouring nest, which provisions are also
overrun with caterpillars. Or I can make shorter work of it by taking
the whole bunch, well covered with the troop, of the first pouch and
planting it right beside the bunch of the second, so that the leaves of
the two mingle a little at the edges.

There is not the least quarrelling between the real proprietors and the
new arrivals. Both go on peacefully browsing, as though nothing had
happened. And all without hesitation, when bed-time comes, make for the
nest, like brothers who have always lived together; all do some
spinning before retiring to rest, thicken the blanket a little and are
then swallowed up in the dormitory. By repeating the same operation
next day and, if necessary, the day after, in order to collect the
laggards, I succeed without the slightest difficulty in wholly
depopulating the first nest and transferring all its caterpillars to
the second.

I venture to do something better still. The same method of
transportation allows me to quadruple the output of a spinning-mill by
adding to it the workers of three similar establishments. And, if I
limit myself to this increase, the reason is not that any confusion
manifests itself in this shifting of quarters, but that I see no bounds
to my experiment, so cheerfully do the caterpillars accept any addition
to their number. The more spinners, the more spinning: a very judicious
rule of conduct.

Let us add that the caterpillars which have been transported cherish no
regrets for their old house. They are quite at home with the others and
make no attempt to regain the nest whence they were banished by my
artifices. It is not the distance that discourages them, for the empty
dwelling is only half a yard away at most. If, for the purpose of my
studies, I wish to restock the deserted nest, I am obliged once more to
resort to transportation, which invariably proves successful.

Later, in February, when an occasional fine day allows of long
processions on the walls and the sand-covered shelf of the greenhouse,
I am able to watch the fusing of two groups without personally
intervening. All that I have to do is patiently to follow the
evolutions of a file on the march. I see it sometimes, after leaving
one nest, enter a different one, guided by some fortuitous change of
route. Thenceforward the strangers form part of the community on the
same footing as the others. In a like fashion, when the caterpillars
walk abroad upon the tree at night, the scanty groups of the outset
must increase and gather the number of spinners which an extensive
building requires.

Everything for everybody. So says the Pine Processionary, nibbling his
leaves without quarrelling in the least over his neighbours’ mouthfuls,
or else entering—and being always peacefully received—another’s home
precisely as he would his own. Whether a member of the tribe or a
stranger, he finds room in the refectory and room in the dormitory. The
others’ nest is his nest. The others’ grazing-ground is his
grazing-ground, in which he is entitled to his fair share, one neither
greater nor smaller than the share of his habitual or casual
companions.

Each for all and all for each. So says the Processionary, who every
evening spends his little capital of silk on enlarging a shelter that
is often new to him. What would he do with his puny skein, if alone?
Hardly anything. But there are hundreds and hundreds of them in the
spinning-mill; and the result of their infinitesimal contributions,
woven into a common stuff, is a thick blanket capable of resisting the
winter. In working for himself, each works for the others; and these on
their side work as zealously for each. O lucky animals that know
nothing of property, the mother of strife! O enviable cenobites, who
practise the strictest communism!

These habits of the caterpillars invite a few reflections. Generous
minds, richer in illusions than in logic, set communism before us as
the sovran cure for human ills. Is it practicable among mankind? At all
times there have been, there still are and there always will be,
fortunately, associations in which it is possible to forget in common
some small part of the hardships of life; but is it possible to
generalize?

The caterpillars of the pine can give us much valuable information in
this respect. Let us have no false shame: our material needs are shared
by the animals; they struggle as we do to take part in the general
banquet of the living; and the manner in which they solve the problem
of existence is not to be despised. Let us then ask ourselves what are
the reasons that cause cenobitism to flourish among the
Processionaries.

One answer suggests itself inevitably, to begin with: the food problem,
that terrible disturber of the world’s tranquillity, is here
non-existent. Peace reigns as soon as the stomach is certain of being
filled without a struggle. A pine-needle or even less suffices for the
caterpillar’s meal; and that needle is always there, waiting to be
eaten, is there in inexhaustible numbers, almost on the threshold of
the home. When dinner-time arrives, we caterpillars go out, we take the
air, we walk a little in procession; then, without laborious seeking,
without jealous rivalries, we seat ourselves at the banquet. The table
is plentifully spread and will never be bare, so large and generous is
the pine; all that we need do is, from one evening to the next, to move
our dining-room a little farther on. Consequently, there are no present
and no future cares on the subject of provisions: the caterpillar finds
food to eat almost as easily as he finds air to breathe.

The atmosphere feeds all creatures on air with a bounty which it is not
necessary to crave. All unknown to itself, without the agency of any
effort or labour, the animal receives its share of the most vital of
elements. The niggardly earth, on the contrary, surrenders its gifts
only when laboriously forced. Not fruitful enough to satisfy every
need, it leaves the division of the food to the fierce eagerness of
competition.

The mouthful to be procured engenders war between consumers. Look at
two Ground-beetles coming at the same time upon a bit of Earth-worm.
Which of the two shall have the morsel? The matter shall be decided by
battle, desperate, ferocious battle. With these famished ones, who eat
at long intervals and do not always eat their fill, communal life is
out of the question.

The Pine Caterpillar is free from these woes. He finds the earth as
generous as the atmosphere; he finds eating as easy as breathing. Other
instances of perfect communism might be named. All occur among species
living on a vegetable diet, provided however that victuals are
plentiful and obtainable without a hard search. An animal diet, on the
contrary, a prey, always more or less difficult to secure, banishes
cenobitism. Where the portion is too small for one, what excuse would
there be for guests?

The Pine Processionary knows nothing of privation. He knows as little
of family ties, another source of unrelenting competition. To make
ourselves a place in the sun is but a half of the struggle imposed upon
us by life: we must also, as far as possible, prepare a place for our
successors; and, as the preservation of the species is of greater
importance than that of the individual, the struggle for the future is
even fiercer than the struggle for the present. Every mother regards
the welfare of her offspring as her primary law. Perish all else,
provided that the brood flourish! Every one for himself is her maxim,
imposed by the rigours of the general conflict; every one for himself
is her rule, the safeguard of the future.

With maternity and its imperious duties, communism ceases to be
practicable. At first sight, certain Hymenoptera [10] seem to declare
the contrary. We find, for instance, the Mason-bees of the Sheds [11]
nesting in myriads on the same tiles and building a monumental edifice
at which all the mothers work. Is this really a community? Not at all.
It is a city in which the inhabitants have neighbours, not
collaborators. Each mother kneads her pots of honey; each amasses a
dowry for her offspring and nothing but a dowry for her offspring; each
wears herself out for her family and only for her family. Oh, it would
be a serious business if some one merely came and alighted on the brim
of a cell that did not belong to her; the mistress of the house would
give her to understand, by means of a sound drubbing, that manners such
as those are not to be endured! She would have to skedaddle very
quickly, unless she wanted a fight. The rights of property are sacred
here.

Even the much more social Hive-bee is no exception to the rule of
maternal egoism. To each hive one mother. If there be two, civil war
breaks out and one of them perishes by the other’s dagger or else quits
the country, followed by a part of the swarm. Although virtually fit to
lay eggs, the other Bees, to the number of some twenty thousand,
renounce maternity and vow themselves to celibacy in order to bring up
the prodigious family of the one and only mother. Here, communism
reigns, under certain aspects; but, for the immense majority,
motherhood is forthwith abolished.

Even so with the Wasps, the Ants, the Termites [12] and the various
social insects. Life in common costs them dear. Thousands and thousands
remain incomplete and become the humble auxiliaries of a few who are
sexually endowed. But, whenever maternity is the general portion,
individualism reappears, as among the Mason-bees, notwithstanding their
show of communism.

The Pine Caterpillars are exempt from the duty of preserving the race.
They have no sex, or rather are obscurely preparing one, as undecided
and rudimentary as all that is not yet but must one day be. With the
blossoming of maternity, that flower of adult age, individual property
will not fail to appear, attended by its rivalries. The insect now so
peaceable will, like the others, have its displays of selfish
intolerance. The mothers will isolate themselves, jealous of the double
pine-needle in which the cylinder of eggs is to be fixed; the males,
fluttering their wings, will challenge one another for the possession
of the coveted bride. It is not a serious struggle among these
easy-going ones, but still it presents a faint picture of those mortal
affrays which the mating so often produces. Love rules the world by
battle; it too is a hotbed of competition.

The caterpillar, being almost sexless, is indifferent to amorous
instincts. This is the first condition for living pacifically in
common. But it is not enough. The perfect concord of the community
demands among all its members an equal division of strength and talent,
of taste and capacity for work. This condition, which perhaps is the
most important of all, is fulfilled preeminently. If there were
hundreds, if there were thousands of them in the same nest, there would
be no difference between any of them.

They are all the same size and equally strong; all wear the same dress;
all possess the same gift for spinning; and all with equal zeal expend
the contents of their silk-glands for the general welfare. No one
idles, no one lounges along when there is work to be done. With no
other stimulus than the satisfaction of doing their duty, every
evening, when the weather is favourable, they all spin with equal
industry and drain to the last drop their reservoirs of silk, which
have become distended during the day. In their tribe there is no
question of skilled or unskilled, of strong or weak, of abstemious or
gluttonous; there are neither hard-workers nor idlers, neither savers
nor spendthrifts. What one does the others do, with a like zeal, no
more and no less well. It is a splendid world of equality truly, but,
alas, a world of caterpillars!

If it suited us to go to school to the Pine Processionary, we should
soon see the inanity of our levelling and communistic theories.
Equality is a magnificent political catchword, but little more. Where
is it, this equality of ours? In our social groups, could we find as
many as two persons exactly equal in strength, health, intelligence,
capacity for work, foresight and all the other gifts which are the
great factors of prosperity? Where should we find anything analogous to
the exact parity prevailing among caterpillars? Nowhere. Inequality is
our law. And a good thing, too.

A sound which is invariably the same, however often multiplied, does
not constitute a harmony. We need dissimilarities, sounds loud and
soft, deep and shrill; we need even discords which, by their harshness,
throw into relief the sweetness of the chords. In the same way, human
societies are harmonious only with the aid of contraries. If the dreams
of our levellers could be realized, we should sink to the monotony of
the caterpillar societies; art, science, progress and the lofty flights
of the imagination would slumber indefinitely in the dead calm of
mediocrity.

Besides, if this general levelling were effected, we should still be
very far from communism. To achieve that, we should have to do away
with the family, as the caterpillars and Plato teach us; we should need
abundance of food obtained without any effort. So long as a mouthful of
bread is difficult to acquire, demanding an industry and labour of
which we are not all equally capable, so long as the family remains the
sacred reason for our foresight, so long will the generous theory of
all for each and each for all be absolutely impracticable.

And then should we gain by abolishing the struggle for the daily bread
of ourselves and those dependent on us? It is very doubtful. We should
be getting rid of this world’s two great joys, work and the family, the
only joys that give any value to life; we should be stifling exactly
that which makes our greatness. And the result of this bestial
sacrilege would be a community of human caterpillars. Thus does the
Pine Processionary teach us by his example.



CHAPTER III

THE PINE PROCESSIONARY: THE PROCESSION


Drover Dingdong’s Sheep followed the Ram which Panurge had maliciously
thrown overboard and leapt nimbly into the sea, one after the other,
“for you know,” says Rabelais, “it is the nature of the sheep always to
follow the first, wheresoever it goes; which makes Aristotle mark them
for the most silly and foolish animals in the world.” [13]

The Pine Caterpillar is even more sheep-like, not from foolishness, but
from necessity: where the first goes all the others go, in a regular
string, with not an empty space between them.

They proceed in single file, in a continuous row, each touching with
its head the rear of the one in front of it. The complex twists and
turns described in his vagaries by the caterpillar leading the van are
scrupulously described by all the others. No Greek theoria winding its
way to the Eleusinian festivals was ever more orderly. Hence the name
of Processionary given to the gnawer of the pine.

His character is complete when we add that he is a rope-dancer all his
life long: he walks only on the tight-rope, a silken rail placed in
position as he advances. The caterpillar who chances to be at the head
of the procession dribbles his thread without ceasing and fixes it on
the path which his fickle preferences cause him to take. The thread is
so tiny that the eye, though armed with a magnifying-glass, suspects it
rather than sees it.

But a second caterpillar steps on the slender footboard and doubles it
with his thread; a third trebles it; and all the others, however many
there be, add the sticky spray from their spinnerets, so much so that,
when the procession has marched by, there remains, as a record of its
passing, a narrow white ribbon whose dazzling whiteness shimmers in the
sun. Very much more sumptuous than ours, their system of road-making
consists in upholstering with silk instead of macadamizing. We sprinkle
our roads with broken stones and level them by the pressure of a heavy
steam-roller; they lay over their paths a soft satin rail, a work of
general interest to which each contributes his thread.

What is the use of all this luxury? Could they not, like other
caterpillars, walk about without these costly preparations? I see two
reasons for their mode of progression. It is night when the
Processionaries sally forth to browse upon the pine-leaves. They leave
their nest, situated at the top of a bough, in profound darkness; they
go down the denuded pole till they come to the nearest branch that has
not yet been gnawed, a branch which becomes lower and lower by degrees
as the consumers finish stripping the upper storeys; they climb up this
untouched branch and spread over the green needles.

When they have had their suppers and begin to feel the keen night air,
the next thing is to return to the shelter of the house. Measured in a
straight line, the distance is not great, hardly an arm’s length; but
it cannot be covered in this way on foot. The caterpillars have to
climb down from one crossing to the next, from the needle to the twig,
from the twig to the branch, from the branch to the bough and from the
bough, by a no less angular path, to go back home. It is useless to
rely upon sight as a guide on this long and erratic journey. The
Processionary, it is true, has five ocular specks on either side of his
head, but they are so infinitesimal, so difficult to make out through
the magnifying-glass, that we cannot attribute to them any great power
of vision. Besides, what good would those short-sighted lenses be in
the absence of light, in black darkness?

It is equally useless to think of the sense of smell. Has the
Processional any olfactory powers or has he not? I do not know. Without
giving a positive answer to the question, I can at least declare that
his sense of smell is exceedingly dull and in no way suited to help him
find his way. This is proved, in my experiments, by a number of hungry
caterpillars that, after a long fast, pass close beside a pine-branch
without betraying any eagerness or showing a sign of stopping. It is
the sense of touch that tells them where they are. So long as their
lips do not chance to light upon the pasture-land, not one of them
settles there, though he be ravenous. They do not hasten to food which
they have scented from afar; they stop at a branch which they encounter
on their way.

Apart from sight and smell, what remains to guide them in returning to
the nest? The ribbon spun on the road. In the Cretan labyrinth, Theseus
would have been lost but for the clue of thread with which Ariadne
supplied him. The spreading maze of the pine-needles is, especially at
night, as inextricable a labyrinth as that constructed for Minos. The
Processionary finds his way through it, without the possibility of a
mistake, by the aid of his bit of silk. At the time for going home,
each easily recovers either his own thread or one or other of the
neighbouring threads, spread fanwise by the diverging herd; one by one
the scattered tribe line up on the common ribbon, which started from
the nest; and the sated caravan finds its way back to the manor with
absolute certainty.

Longer expeditions are made in the daytime, even in winter, if the
weather be fine. Our caterpillars then come down from the tree, venture
on the ground, march in procession for a distance of thirty yards or
so. The object of these sallies is not to look for food, for the native
pine-tree is far from being exhausted: the shorn branches hardly count
amid the vast leafage. Moreover, the caterpillars observe complete
abstinence till nightfall. The trippers have no other object than a
constitutional, a pilgrimage to the outskirts to see what these are
like, possibly an inspection of the locality where, later on, they mean
to bury themselves in the sand for their metamorphosis.

It goes without saying that, in these greater evolutions, the guiding
cord is not neglected. It is now more necessary than ever. All
contribute to it from the produce of their spinnerets, as is the
invariable rule whenever there is a progression. Not one takes a step
forward without fixing to the path the thread hanging from his lip.

If the series forming the procession be at all long, the ribbon is
dilated sufficiently to make it easy to find; nevertheless, on the
homeward journey, it is not picked up without some hesitation. For
observe that the caterpillars when on the march never turn completely;
to wheel round on their tight-rope is a method utterly unknown to them.
In order therefore to regain the road already covered, they have to
describe a zig-zag whose windings and extent are determined by the
leader’s fancy. Hence come gropings and roamings which are sometimes
prolonged to the point of causing the herd to spend the night out of
doors. It is not a serious matter. They collect into a motionless
cluster. To-morrow the search will start afresh and will sooner or
later be successful. Oftener still the winding curve meets the
guide-thread at the first attempt. As soon as the first caterpillar has
the rail between his legs, all hesitation ceases; and the band makes
for the nest with hurried steps.

The use of this silk-tapestried roadway is evident from a second point
of view. To protect himself against the severity of the winter which he
has to face when working, the Pine Caterpillar weaves himself a shelter
in which he spends his bad hours, his days of enforced idleness. Alone,
with none but the meagre resources of his silk-glands, he would find
difficulty in protecting himself on the top of a branch buffeted by the
winds. A substantial dwelling, proof against snow, gales and icy fogs,
requires the cooperation of a large number. Out of the individual’s
piled-up atoms, the community obtains a spacious and durable
establishment.

The enterprise takes a long time to complete. Every evening, when the
weather permits, the building has to be strengthened and enlarged. It
is indispensable, therefore, that the corporation of workers should not
be dissolved while the stormy season continues and the insects are
still in the caterpillar stage. But, without special arrangements, each
nocturnal expedition at grazing-time would be a cause of separation. At
that moment of appetite for food there is a return to individualism.
The caterpillars become more or less scattered, settling singly on the
branches around; each browses his pine-needle separately. How are they
to find one another afterwards and become a community again?

The several threads left on the road make this easy. With that guide,
every caterpillar, however far he may be, comes back to his companions
without ever missing the way. They come hurrying from a host of twigs,
from here, from there, from above, from below; and soon the scattered
legion reforms into a group. The silk thread is something more than a
road-making expedient: it is the social bond, the system that keeps the
members of the community indissolubly united.

At the head of every procession, long or short, goes a first
caterpillar whom I will call the leader of the march or file, though
the word leader, which I use for want of a better, is a little out of
place here. Nothing, in fact, distinguishes this caterpillar from the
others: it just depends upon the order in which they happen to line up;
and mere chance brings him to the front. Among the Processionaries,
every captain is an officer of fortune. The actual leader leads;
presently he will be a subaltern, if the file should break up in
consequence of some accident and be formed anew in a different order.

His temporary functions give him an attitude of his own. While the
others follow passively in a close file, he, the captain, tosses
himself about and with an abrupt movement flings the front of his body
hither and thither. As he marches ahead he seems to be seeking his way.
Does he in point of fact explore the country? Does he choose the most
practicable places? Or are his hesitations merely the result of the
absence of a guiding thread on ground that has not yet been covered?
His subordinates follow very placidly, reassured by the cord which they
hold between their legs; he, deprived of that support, is uneasy.

Why cannot I read what passes under his black, shiny skull, so like a
drop of tar? To judge by actions, there is here a small dose of
discernment which is able, after experimenting, to recognize excessive
roughnesses, over-slippery surfaces, dusty places that offer no
resistance and, above all, the threads left by other excursionists.
This is all or nearly all that my long acquaintance with the
Processionaries has taught me as to their mentality. Poor brains,
indeed; poor creatures, whose commonwealth has its safety hanging upon
a thread!

The processions vary greatly in length. The finest that I have seen
manœuvring on the ground measured twelve or thirteen yards and numbered
about three hundred caterpillars, drawn up with absolute precision in a
wavy line. But, if there were only two in a row, the order would still
be perfect: the second touches and follows the first.

By February I have processions of all lengths in the greenhouse. What
tricks can I play upon them? I see only two: to do away with the
leader; and to cut the thread.

The suppression of the leader of the file produces nothing striking. If
the thing is done without creating a disturbance, the procession does
not alter its ways at all. The second caterpillar, promoted to captain,
knows the duties of his rank off-hand: he selects and leads, or rather
he hesitates and gropes.

The breaking of the silk ribbon is not very important either. I remove
a caterpillar from the middle of the file. With my scissors, so as not
to cause a commotion in the ranks, I cut the piece of ribbon on which
he stood and clear away every thread of it. As a result of this breach,
the procession acquires two marching leaders, each independent of the
other. It may be that the one in the rear joins the file ahead of him,
from which he is separated by but a slender interval; in that case,
things return to their original condition. More frequently, the two
parts do not become reunited. In that case, we have two distinct
processions, each of which wanders where it pleases and diverges from
the other. Nevertheless, both will be able to return to the nest by
discovering sooner or later, in the course of their peregrinations, the
ribbon on the other side of the break.

These two experiments are only moderately interesting. I have thought
out another, one more fertile in possibilities. I propose to make the
caterpillars describe a close circuit, after the ribbons running from
it and liable to bring about a change of direction have been destroyed.
The locomotive engine pursues its invariable course so long as it is
not shunted on to a branch-line. If the Processionaries find the silken
rail always clear in front of them, with no switches anywhere, will
they continue on the same track, will they persist in following a road
that never comes to an end? What we have to do is to produce this
circuit, which is unknown under ordinary conditions, by artificial
means.

The first idea that suggests itself is to seize with the forceps the
silk ribbon at the back of the train, to bend it without shaking it and
to bring the end of it ahead of the file. If the caterpillar marching
in the van steps upon it, the thing is done: the others will follow him
faithfully. The operation is very simple in theory but very difficult
in practice and produces no useful results. The ribbon, which is
extremely slight, breaks under the weight of the grains of sand that
stick to it and are lifted with it. If it does not break, the
caterpillars at the back, however delicately we may go to work, feel a
disturbance which makes them curl up or even let go.

There is a yet greater difficulty: the leader refuses the ribbon laid
before him; the cut end makes him distrustful. Failing to see the
regular, uninterrupted road, he slants off to the right or left, he
escapes at a tangent. If I try to interfere and to bring him back to
the path of my choosing, he persists in his refusal, shrivels up, does
not budge; and soon the whole procession is in confusion. We will not
insist: the method is a poor one, very wasteful of effort for at best a
problematical success.

We ought to interfere as little as possible and obtain a natural closed
circuit. Can it be done? Yes. It lies in our power, without the least
meddling, to see a procession march along a perfect circular track. I
owe this result, which is eminently deserving of our attention, to pure
chance.

On the shelf with the layer of sand in which the nests are planted
stand some big palm-vases measuring nearly a yard and a half in
circumference at the top. The caterpillars often scale the sides and
climb up to the moulding which forms a cornice around the opening. This
place suits them for their processions, perhaps because of the absolute
firmness of the surface, where there is no fear of landslides, as on
the loose, sandy soil below; and also, perhaps, because of the
horizontal position, which is favorable to repose after the fatigue of
the ascent. It provides me with a circular track all ready-made. I have
nothing to do but wait for an occasion propitious to my plans. This
occasion is not long in coming.

On the 30th of January, 1896, a little before twelve o’clock in the
day, I discover a numerous troop making their way up and gradually
reaching the popular cornice. Slowly, in single file, the caterpillars
climb the great vase, mount the ledge and advance in regular
procession, while others are constantly arriving and continuing the
series. I wait for the string to close up, that is to say, for the
leader, who keeps following the circular moulding, to return to the
point from which he started. My object is achieved in a quarter of an
hour. The closed circuit is realized magnificently, in something very
nearly approaching a circle.

The next thing is to get rid of the rest of the ascending column, which
would disturb the fine order of the procession by an excess of
newcomers; it is also important that we should do away with all the
silken paths, both new and old, that can put the cornice into
communication with the ground. With a thick hair-pencil I sweep away
the surplus climbers; with a big brush, one that leaves no smell behind
it—for this might afterwards prove confusing—I carefully rub down the
vase and get rid of every thread which the caterpillars have laid on
the march. When these preparations are finished, a curious sight awaits
us.

In the uninterrupted circular procession there is no longer a leader.
Each caterpillar is preceded by another on whose heels he follows,
guided by the silk track, the work of the whole party; he again has a
companion close behind him, following him in the same orderly way. And
this is repeated without variation throughout the length of the chain.
None commands, or rather none modifies the trail according to his
fancy; all obey, trusting in the guide who ought normally to lead the
march and who in reality has been abolished by my trickery.

From the first circuit of the edge of the tub the rail of silk has been
laid in position and is soon turned into a narrow ribbon by the
procession, which never ceases dribbling its thread as it goes. The
rail is simply doubled and has no branches anywhere, for my brush has
destroyed them all. What will the caterpillars do on this deceptive,
closed path? Will they walk endlessly round and round until their
strength gives out entirely?

The old schoolmen were fond of quoting Buridan’s [14] Ass, that famous
Donkey who, when placed between two bundles of hay, starved to death
because he was unable to decide in favour of either by breaking the
equilibrium between two equal but opposite attractions. They slandered
the worthy animal. The Ass, who is no more foolish than any one else,
would reply to the logical snare by feasting off both bundles. Will my
caterpillars show a little of his mother wit? Will they, after many
attempts, be able to break the equilibrium of their closed circuit,
which keeps them on a road without a turning? Will they make up their
minds to swerve to this side or that, which is the only method of
reaching their bundle of hay, the green branch yonder, quite near, not
two feet off?

I thought that they would and I was wrong. I said to myself:

“The procession will go on turning for some time, for an hour, two
hours perhaps; then the caterpillars will perceive their mistake. They
will abandon the deceptive road and make their descent somewhere or
other.”

That they should remain up there, hard pressed by hunger and the lack
of cover, when nothing prevented them from going away, seemed to me
inconceivable imbecility. Facts, however, forced me to accept the
incredible. Let us describe them in detail.

The circular procession begins, as I have said, on the 30th of January,
about midday, in splendid weather. The caterpillars march at an even
pace, each touching the stern of the one in front of him. The unbroken
chain eliminates the leader with his changes of direction; and all
follow mechanically, as faithful to their circle as are the hands of a
watch. The headless file has no liberty left, no will; it has become
mere clock-work. And this continues for hours and hours. My success
goes far beyond my wildest suspicions. I stand amazed at it, or rather
I am stupefied.

Meanwhile, the multiplied circuits change the original rail into a
superb ribbon a twelfth of an inch broad. I can easily see it
glittering on the red ground of the pot. The day is drawing to a close
and no alteration has yet taken place in the position of the trail. A
striking proof confirms this.

The trajectory is not a plane curve, but one which, at a certain point,
deviates and goes down a little way to the lower surface of the
cornice, returning to the top some eight inches farther. I marked these
two points of deviation in pencil on the vase at the outset. Well, all
that afternoon and, more conclusive still, on the following days, right
to the end of this mad dance, I see the string of caterpillars dip
under the ledge at the first point and come to the top again at the
second. Once the first thread is laid, the road to be pursued is
permanently established.

If the road does not vary, the speed does. I measure nine centimetres
[15] a minute as the average distance covered. But there are more or
less lengthy halts; the pace slackens at times, especially when the
temperature falls. At ten o’clock in the evening the walk is little
more than a lazy swaying of the body. I foresee an early halt, in
consequence of the cold, of fatigue and doubtless also of hunger.

Grazing-time has arrived. The caterpillars have come crowding from all
the nests in the greenhouse to browse upon the pine-branches planted by
myself beside the silken purses. Those in the garden do the same, for
the temperature is mild. The others, lined up along the earthenware
cornice, would gladly take part in the feast; they are bound to have an
appetite after a ten hours’ walk. The branch stands green and tempting
not a hand’s breadth away. To reach it they need but go down; and the
poor wretches, foolish slaves of their ribbon that they are, cannot
make up their minds to do so. I leave the famished ones at half-past
ten, persuaded that they will take counsel with their pillow and that
on the morrow things will have resumed their ordinary course.

I was wrong. I was expecting too much of them when I accorded them that
faint gleam of intelligence which the tribulations of a distressful
stomach ought, one would think, to have aroused. I visit them at dawn.
They are lined up as on the day before, but motionless. When the air
grows a little warmer, they shake off their torpor, revive and start
walking again. The circular procession begins anew, like that which I
have already seen. There is nothing more and nothing less to be noted
in their machine-like obstinacy.

This time it is a bitter night. A cold snap has supervened, was indeed
foretold in the evening by the garden caterpillars, who refused to come
out despite appearances which to my duller senses seemed to promise a
continuation of the fine weather. At daybreak the rosemary-walks are
all asparkle with rime and for the second time this year there is a
sharp frost. The large pond in the garden is frozen over. What can the
caterpillars in the conservatory be doing? Let us go and see.

All are ensconced in their nests, except the stubborn processionists on
the edge of the vase, who, deprived of shelter as they are, seem to
have spent a very bad night. I find them clustered in two heaps,
without any attempt at order. They have suffered less from the cold,
thus huddled together.

’Tis an ill wind that blows nobody any good. The severity of the night
has caused the ring to break into two segments which will, perhaps,
afford a chance of safety. Each group, as it revives and resumes its
walk, will presently be headed by a leader who, not being obliged to
follow a caterpillar in front of him, will possess some liberty of
movement and perhaps be able to make the procession swerve to one side.
Remember that, in the ordinary processions, the caterpillar walking
ahead acts as a scout. While the others, if nothing occurs to create
excitement, keep to their ranks, he attends to his duties as a leader
and is continually turning his head to this side and that,
investigating, seeking, groping, making his choice. And things happen
as he decides: the band follows him faithfully. Remember also that,
even on a road which has already been travelled and beribboned, the
guiding caterpillar continues to explore.

There is reason to believe that the Processionaries who have lost their
way on the ledge will find a chance of safety here. Let us watch them.
On recovering from their torpor, the two groups line up by degrees into
two distinct files. There are therefore two leaders, free to go where
they please, independent of each other. Will they succeed in leaving
the enchanted circle? At the sight of their large black heads swaying
anxiously from side to side, I am inclined to think so for a moment.
But I am soon undeceived. As the ranks fill out, the two sections of
the chain meet and the circle is reconstituted. The momentary leaders
once more become simple subordinates; and again the caterpillars march
round and round all day.

For the second time in succession, the night, which is very calm and
magnificently starry, brings a hard frost. In the morning the
Processionaries on the tub, the only ones who have camped out
unsheltered, are gathered into a heap which largely overflows both
sides of the fatal ribbon. I am present at the awakening of the numbed
ones. The first to take the road is, as luck will have it, outside the
track. Hesitatingly he ventures into unknown ground. He reaches the top
of the rim and descends upon the other side on the earth in the vase.
He is followed by six others, no more. Perhaps the rest of the troop,
who have not fully recovered from their nocturnal torpor, are to lazy
to bestir themselves.

The result of this brief delay is a return to the old track. The
caterpillars embark on the silken trail and the circular march is
resumed, this time in the form of a ring with a gap in it. There is no
attempt, however, to strike a new course on the part of the guide whom
this gap has placed at the head. A chance of stepping outside the magic
circle has presented itself at last; and he does not know how to avail
himself of it.

As for the caterpillars who have made their way to the inside of the
vase, their lot is hardly improved. They climb to the top of the palm,
starving and seeking for food. Finding nothing to eat that suits them,
they retrace their steps by following the thread which they have left
on the way, climb the ledge of the pot, strike the procession again
and, without further anxiety, slip back into the ranks. Once more the
ring is complete, once more the circle turns and turns.

Then when will the deliverance come? There is a legend that tells of
poor souls dragged along in an endless round until the hellish charm is
broken by a drop of holy water. What drop will good fortune sprinkle on
my Processionaries to dissolve their circle and bring them back to the
nest? I see only two means of conjuring the spell and obtaining a
release from the circuit. These two means are two painful ordeals. A
strange linking of cause and effect: from sorrow and wretchedness good
is to come.

And, first, shrivelling as the result of cold. The caterpillars gather
together without any order, heap themselves some on the path, some,
more numerous these, outside it. Among the latter there may be, sooner
or later, some revolutionary who, scorning the beaten track, will trace
out a new road and lead the troop back home. We have just seen an
instance of it. Seven penetrated to the interior of the vase and
climbed the palm. True, it was an attempt with no result, but still an
attempt. For complete success, all that need be done would have been to
take the opposite slope. An even chance is a great thing. Another time
we shall be more successful.

In the second place, the exhaustion due to fatigue and hunger. A lame
one stops, unable to go farther. In front of the defaulter the
procession still continues to wend its way for a short time. The ranks
close up and an empty space appears. On coming to himself and resuming
the march, the caterpillar who has caused the breach becomes a leader,
having nothing before him. The least desire for emancipation is all
that he wants to make him launch the band into a new path which perhaps
will be the saving path.

In short, when the Processionaries’ train is in difficulties, what it
needs, unlike ours, is to run off the rails. The side-tracking is left
to the caprice of a leader who alone is capable of turning to the right
or left; and this leader is absolutely non-existent so long as the ring
remains unbroken. Lastly, the breaking of the circle, the one stroke of
luck, is the result of a chaotic halt, caused principally by excess of
fatigue or cold.

The liberating accident, especially that of fatigue, occurs fairly
often. In the course of the same day, the moving circumference is cut
up several times into two or three sections; but continuity soon
returns and no change takes place. Things go on just the same. The bold
innovator who is to save the situation has not yet had his inspiration.

There is nothing new on the fourth day, after an icy night like the
previous one; nothing to tell except the following detail. Yesterday I
did not remove the trace left by the few caterpillars who made their
way to the inside of the vase. This trace, together with a junction
connecting it with the circular road, is discovered in the course of
the morning. Half the troop takes advantage of it to visit the earth in
the pot and climb the palm; the other half remains on the ledge and
continues to walk along the old rail. In the afternoon the band of
emigrants rejoins the others, the circuit is completed and things
return to their original condition.

We come to the fifth day. The night frost becomes more intense, without
however as yet reaching the greenhouse. It is followed by bright
sunshine in a calm and limpid sky. As soon as the sun’s rays have
warmed the panes a little, the caterpillars, lying in heaps, wake up
and resume their evolutions on the ledge of the vase. This time the
fine order of the beginning is disturbed and a certain disorder becomes
manifest, apparently an omen of deliverance near at hand. The
scouting-path inside the vase, which was upholstered in silk yesterday
and the day before, is to-day followed to its origin on the rim by a
part of the band and is then abandoned after a short loop. The other
caterpillars follow the usual ribbon. The result of this bifurcation is
two almost equal files, walking along the ledge in the same direction,
at a short distance from each other, sometimes meeting, separating
farther on, in every case with some lack of order.

Weariness increases the confusion. The crippled, who refuse to go on,
are many. Breaches increase; files are split up into sections each of
which has its leader, who pokes the front of his body this way and that
to explore the ground. Everything seems to point to the disintegration
which will bring safety. My hopes are once more disappointed. Before
the night the single file is reconstituted and the invincible gyration
resumed.

Heat comes, just as suddenly as the cold did. To-day, the 4th of
February, is a beautiful, mild day. The greenhouse is full of life.
Numerous festoons of caterpillars, issuing from the nests, meander
along the sand on the shelf. Above them, at every moment, the ring on
the ledge of the vase breaks up and comes together again. For the first
time I see daring leaders who, drunk with heat, standing only on their
hinder prolegs at the extreme edge of the earthenware rim, fling
themselves forward into space, twisting about, sounding the depths. The
endeavour is frequently repeated, while the whole troop stops. The
caterpillars’ heads give sudden jerks; their bodies wriggle.

One of the pioneers decides to take the plunge. He slips under the
ledge. Four follow him. The others, still confiding in the perfidious
silken path, dare not copy him and continue to go along the old road.

The short string detached from the general chain gropes about a great
deal, hesitates long on the side of the vase; it goes half-way down,
then climbs up again slantwise, rejoins and takes its place in the
procession. This time the attempt has failed, though at the foot of the
vase, not nine inches away, there lay a bunch of pine-needles which I
had placed there with the object of enticing the hungry ones. Smell and
sight told them nothing. Near as they were to the goal, they went up
again.

No matter, the endeavour has its uses. Threads were laid on the way and
will serve as a lure to further enterprise. The road of deliverance has
its first landmarks. And two days later, on the eighth day of the
experiment, the caterpillars—now singly, anon in small groups, then
again in strings of some length—come down from the ledge by following
the staked-out path. At sunset the last of the laggards is back in the
nest.

Now for a little arithmetic. For seven times twenty-four hours the
caterpillars have remained on the ledge of the vase. To make an ample
allowance for stops due to the weariness of this one or that and above
all for the rest taken during the colder hours of the night, we will
deduct one-half of the time. This leaves eighty-four hours’ walking.
The average pace is nine centimetres [16] a minute. The aggregate
distance covered, therefore, is 453 metres, a good deal more than a
quarter of a mile, which is a great walk for these little crawlers. The
circumference of the vase, the perimeter of the track, is exactly 1 m.
35. [17] Therefore the circle covered, always in the same direction and
always without result, was described three hundred and thirty-five
times.

These figures surprise me, though I am already familiar with the
abysmal stupidity of insects as a class whenever the least accident
occurs. I feel inclined to ask myself whether the Processionaries were
not kept up there so long by the difficulties and dangers of the
descent rather than by the lack of any gleam of intelligence in their
benighted minds. The facts, however, reply that the descent is as easy
as the ascent.

The caterpillar has a very supple back, well adapted for twisting round
projections or slipping underneath. He can walk with the same ease
vertically or horizontally, with his back down or up. Besides, he never
moves forward until he has fixed his thread to the ground. With this
support to his feet, he has no falls to fear, no matter what his
position.

I had a proof of this before my eyes during a whole week. As I have
already said, the track, instead of keeping on one level, bends twice,
dips at a certain point under the ledge of the vase and reappears at
the top a little farther on. At one part of the circuit, therefore, the
procession walks on the lower surface of the rim; and this inverted
position implies so little discomfort or danger that it is renewed at
each turn for all the caterpillars from first to last.

It is out of the question then to suggest the dread of a false step on
the edge of the rim which is so nimbly turned at each point of
inflexion. The caterpillars in distress, starved, shelterless, chilled
with cold at night, cling obstinately to the silk ribbon covered
hundreds of times, because they lack the rudimentary glimmers of reason
which would advice them to abandon it.

Experience and reflection are not in their province. The ordeal of a
five hundred yards’ march and three to four hundred turns teach them
nothing; and it takes casual circumstances to bring them back to the
nest. They would perish on their insidious ribbon if the disorder of
the nocturnal encampments and the halts due to fatigue did not cast a
few threads outside the circular path. Some three or four move along
these trails, laid without an object, stray a little way and, thanks to
their wanderings, prepare the descent, which is at last accomplished in
short strings favoured by chance.

The school most highly honoured to-day is very anxious to find the
origin of reason in the dregs of the animal kingdom. Let me call its
attention to the Pine Processionary.



CHAPTER IV

THE PINE PROCESSIONARY: METEOROLOGY


In January a second moult occurs, leaving the caterpillar less fair to
the eye, while at the same time endowing him with some very peculiar
organs. When the moment has come to shed their skins, the
Processionaries cluster higgledy-piggledy on the dome of the nest and
there, if the weather be mild, remain motionless day and night. It
would seem as though the fact of their contact, of their mutual
discomfort, while thus heaped together, furnishes a resistance, a
fulcrum, which favours the process of excoriation.

After this second moult, the hairs on the middle of the back are of a
dull reddish colour, which is made paler still by the interposition of
numerous long white hairs. But this faded costume is accompanied by the
singular organs which attracted the attention of Réaumur, who was
greatly perplexed as to their function. In the place originally
occupied by the scarlet mosaic, eight segments of the caterpillar are
now cleft by a broad transversal gash, a sort of thick-lipped mouth,
which opens and gapes wide at the caterpillar’s will, or closes without
leaving a visible trace.

From each of these expanding mouths rises a tumour with a fine,
colourless skin, as though the creature were exposing its tender inside
and inflating it, for the appearance is almost that which would be
presented by the viscera protruding through skin incised by the
scalpel. Two large dark-brown dots occupy the front face of the
protuberance. At the back are two short, flat tufts of russet bristles,
which in the sunlight shine with a rich brilliancy. All around is a
radiating border of long white hairs, spread almost flat.

This protuberance is extremely sensitive. At the slightest irritation
it goes in again and disappears under the dark integument. In its place
opens an oval crater, a sort of huge stoma, which swiftly brings its
lips together, closes and entirely disappears. The long white hairs
that form a moustache and imperial around this mouth follow the
movements of the contracting lips. After first radiating from a centre
and lying flat, these hairs rise like levelled wheat which the wind has
caught from beneath and meet to form a transversal crest, perpendicular
to the creature’s back.

This hairy erection produces a sudden modification in the caterpillar’s
aspect. The red shiny bristles have disappeared, buried under the dark
skin; the white hairs, now standing on end, form a hirsute mane; an
ashy tinge has crept into the general colour of the costume.

When calm is restored, as soon happens, the slits open and yawn afresh;
the sensitive protuberances emerge, quick to disappear once more should
any cause for alarm occur. These alternate expansions and contractions
are rapidly repeated. I provoke them at will in various ways. A slight
puff of tobacco-smoke immediately causes the stomata to yawn and the
protuberances to emerge. One would think that the insect was putting
itself on its guard and displaying some special apparatus of
information. Before long the protuberances go in again. A second puff
of smoke brings them out once more. But, if the smoke is too abundant,
too acrid, the caterpillar wriggles and writhes without opening his
apparatus.

Or else I touch one or other of these uncovered protuberances, very
delicately, with a bit of straw. The pimple affected immediately
contracts, draws into itself, like the horns of the Snail, and is
replaced by a gaping mouth, which in its turn closes. Usually, but not
always, the segment excited by the contact of my straw is imitated by
the others, both front and back, which close their apparatus one by
one.

When undisturbed and in repose, the caterpillar generally has his
dorsal slits expanded; in moving, he sometimes opens and sometimes
closes them. In either case expansion and contraction are frequently
repeated. Constantly coming together and retreating under the skin, the
lips of the mouth-like opening therefore end by losing their brittle
moustaches of russet hairs, which break off. In this way a sort of dust
collects at the bottom of the crater, a dust formed of broken hairs,
which, thanks to their barbs, soon collect into little tufts. When the
slit expands rather suddenly, the central projection shoots out on the
insect’s sides its load of hairy remnants, which the least breath blows
into a cloud of golden atoms highly disagreeable to the observer. I
shall have something to say presently of the itch to which he is at
such times exposed.

Are these peculiar stomata designed merely to collect the adjoining
bristles and to grind them to powder? Are these fine-skinned papillæ,
which inflate and ascend from the depths of their hiding-place,
intended to get rid of the accumulation of broken hairs? Or is it the
sole function of this peculiar apparatus to prepare, at the expense of
the caterpillar’s fleece, an irritant dust which shall act as a means
of defence? Nothing tells us so.

Certainly the caterpillar is not armed against the enquirer who from
time to time takes it into his head to come and examine him through a
magnifying-glass. It is even very doubtful whether he troubles at all
about those passionate caterpillar-lovers, Calosoma sycophanta [18]
among insects and the Cuckoo among birds. Those who consume such fare
have a stomach expressly fashioned for the purpose, a stomach that
laughs at blistering hairs and possibly finds an appetizing stimulant
in their sting. No, I do not see the motives that prompted the
Processionary to cleave his back with so many slits, if he merely
strips himself of his hair to throw an irritating dust in our eyes.
There must certainly be something else in question.

Réaumur mentions these openings, of which he made a brief study. He
calls them stigmata and is inclined to take them for exceptional
breathing-holes. That they are not, O my master; no insect contrives
air-holes on its back! Moreover, the magnifying-glass reveals no
channel of communication with the interior. Respiration plays no part
here; the solution of the enigma must lie elsewhere.

The protuberances that rise from those expanded cavities are formed of
a soft, pale, hairless membrane, which gives the impression of a
visceral hernia, as though the caterpillar were wounded and exposing
its delicate entrails to the air. The sensitiveness just here is great.
The lightest touch with the point of a hair-pencil causes the immediate
indrawing of the protuberances and the closing of the containing lips.

The touch of a solid object even is not essential. I pick up a tiny
drop of water on the point of a pin and, without shaking it off,
present this drop to the sensitive projection. At the moment when
contact occurs the apparatus contracts and closes up. The recoil of the
Snail’s horns, withdrawing the visual and olfactory organs into their
sheaths, is no prompter.

Everything seems to prove that these optional tumours, appearing and
disappearing at the caterpillar’s will, are instruments of sensorial
perception. The caterpillar exposes them to obtain information; he
shelters them under his skin to preserve their delicate functions. Now
what is it that they perceive? This is a difficult question, in which
the habits of the Processionary alone can afford us a little guidance.

During the whole winter, the Pine Caterpillars are active only at
night. In the daytime, when the weather is fine, they readily repair to
the dome of the nest and there remain motionless, gathered into heaps.
It is the hour of the open-air siesta, under the pale December and
January sun. As yet none leaves the home. It is quite late in the
evening, towards nine o’clock, when they set out, marching in an
irregular procession, to browse on the leaves of the branches hard by.
Their grazing is a protracted affair. The flock returns late, some time
after midnight, when the temperature falls too low.

Secondly, it is in the heart of winter, during the roughest months,
that the Processionary displays his full activity. Indefatigably at
this time of year he spins, adding each night a new web to his silken
tent; at this time, whenever the weather permits, he ventures abroad on
the neighbouring boughs to feed, to grow and to renew his skein of
silk.

By a very remarkable exception, the harsh season marked by inactivity
and lethargic repose in other insects is for him the season of bustle
and labour, on condition, of course, that the inclemencies of the
weather do not exceed certain limits. If the north wind blow too
violently, so that it is like to sweep the flock away; if the cold be
too piercing, so that there is a risk of freezing to death; if it snow,
or rain, or if the mist thicken into an icy drizzle, the caterpillars
prudently stay at home, sheltering under their weatherproof tent.

It would be convenient to some extent to foresee these inclemencies.
The caterpillar dreads them. A drop of rain sets him in a flutter; a
snowflake exasperates him. To start for the grazing-grounds at dark of
night, in uncertain weather, would be dangerous, for the procession
goes some distance and travels slowly. The flock would fare ill before
regaining shelter did any sudden atmospheric trouble supervene, an
event of some frequency in the bad season of the year. So that he may
be informed in this particular during his nocturnal winter rambles, can
the Pine Caterpillar be endowed with some sort of meteorological
aptitudes? Let us describe how the suspicion occurred to me.

Divulged I know not how, my rearing of caterpillars under glass
acquired a certain renown. It was talked about in the village. The
forest-ranger, a sworn enemy to destructive insects, wanted to see the
grazing of the famous caterpillars, of whom he had retained a too
poignant memory ever since the day when he gathered and destroyed their
nests in a pine-wood under his charge. It was arranged that he should
call the same evening.

He arrives at the appointed hour, accompanied by a friend. For a moment
we sit and chat in front of the fire; then, when the clock strikes
nine, the lantern is lit and we all three enter the greenhouse. The
visitors are eager for the spectacle of which they have heard such
wonderful things, while I am certain of satisfying their curiosity.

But, but ... what is this? Not a caterpillar on the nests, not one on
the fresh ration of branches! Last night and on the previous nights
they came out in countless numbers; to-night not one reveals himself.
Can it be that they are merely late in going to dinner? Can their
habitual punctuality be at fault because appetite has not yet arrived?
We must be patient.... Ten o’clock. Nothing. Eleven. Still nothing.
Midnight was at hand when we abandoned our watch, convinced that it
would be vain to prolong the sitting. You can imagine what an abject
fool I looked at having thus to send my guests away.

Next day I thought that I dimly perceived the explanation of this
disappointment. It rained in the night and again in the morning. Snow,
not the earliest of the year, but so far the most abundant, whitened
the brow of the Ventoux. [19] Had the caterpillars, more sensitive than
any of us to atmospheric changes, refused to venture forth because they
anticipated what was about to happen? Had they foreseen the rain and
the snow, which nothing seemed to announce, at all events to us? After
all, why not? Let us continue to observe them and we shall see whether
the coincidence is fortuitous or not.

On this memorable day, therefore, the 13th of December, 1895, I
institute the caterpillars’ meteorological observatory. I have at my
disposal absolutely none of the apparatus dear to science, not even a
modest thermometer, for my unlucky star continues in the ascendant,
proving as unkind to-day as when I learnt chemistry with pipe-bowls for
crucibles and bottles that once contained sweets for retorts. I confine
myself to visiting nightly the Processionaries in the greenhouse and
those in the garden. It is a hard task, especially as I have to go to
the far end of the enclosure, often in weather when one would not turn
a Dog out of doors. I set down the acts of the caterpillars, whether
they come out or stay at home; I note the state of the sky during the
day and at the moment of my evening examination.

To this list I add the meteorological chart of Europe which the Temps
publishes daily. If I want more precise data, I request the Normal
School at Avignon to send me, on occasions of violent disturbances, the
barometrical records of its observatory. These are the only documents
at my disposal.

Before we come to the results obtained, let me once more repeat that my
caterpillars’ meteorological institute has two stations: one in the
greenhouse and one in the open air, on the pines in the enclosure. The
first, protected against the wind and rain, is that which I prefer: it
provides more regular and more continuous information. In fact, the
open-air caterpillars often enough refuse to come out, even though the
general conditions be favourable. It is enough to keep them at home if
there be too strong a wind shaking the boughs, or even a little
moisture dripping on the web of the nests. Saved from these two perils,
the greenhouse caterpillars have only to consider atmospheric incidents
of a higher order. The small variations escape them; the great alone
make an impression on them: a most useful point for the observer and
going a long way towards solving the problem for him. The colonies
under glass, therefore, provide most of the material for my notes; the
colonies in the open air add their testimony, which is not always quite
clear.

Now what did they tell me, those greenhouse caterpillars who, on the
13th of December, refused to show themselves to my guest, the
forest-ranger? The rain that was to fall that night could hardly have
alarmed them: they were so well sheltered. The snow about to whiten
Mont Ventoux was nothing to them: it was so far away. Moreover, it was
neither snowing yet nor raining. Some extraordinary atmospheric event,
profound and of vast extent, must have been occurring. The charts in
the Temps and the bulletin of the Normal School told me as much.

A cyclonic disturbance, coming from the British Isles, was passing over
our district; an atmospheric depression the like of which the season
had not as yet known, had spread in our direction, reaching us on the
13th and persisting, in a more or less accentuated form, until the
22nd. At Avignon the barometer suddenly fell half an inch, to 29.1 in.,
on the 13th and lower still, to 29 in., on the 19th.

During this period of ten days, the garden caterpillars made no sortie
on the pine-trees. True, the weather was changeable. There were a few
showers of fine rain and some violent gusts of the mistral; but more
frequently there were days and nights when the sky was superb and the
temperature moderate. The prudent anchorites would not allow themselves
to be caught. The low pressure persisted, menacing them; and so they
stopped at home.

In the greenhouse things happen rather differently. Sorties take place,
but the staying-in days are still more numerous. It looks as though the
caterpillars, alarmed at first by the unexpected things happening
overhead, had reassured themselves and resumed work, feeling nothing,
in their shelter, of what they would have suffered out of doors—rain,
snow and furious mistral blasts—and had then suspended their work again
when the threats of bad weather increased.

There is, indeed, a fairly accurate agreement between the oscillations
of the barometer and the decisions of the herd. When the column of
mercury rises a little, they come out; when it falls they remain at
home. Thus on the 19th, the night of the lowest pressure, 29 in., not a
caterpillar ventures outside.

As the wind and rain can have no effect on my colonies under glass, one
is led to suppose that atmospheric pressure, with its physiological
results, so difficult to define, is here the principal factor. As for
the temperature, within moderate limits there is no need to discuss it.
The Processionaries have a robust constitution, as behoves spinners who
work in the open air in midwinter. However piercing the cold, so long
as it does not freeze, when the hour comes for working or feeding they
spin on the surface of the nest or browse on the neighbouring branches.

Another example. According to the meteorological chart in the Temps, a
depression whose centre is near the Iles Sanguinaires, at the entrance
of the Gulf of Ajaccio, reaches my neighbourhood, with a minimum of
29.2 in., on the 9th of January. A tempestuous wind gets up. For the
first time this year there is a respectable frost. The ice on the large
pond in the garden is two or three inches thick. This wild weather
lasts for five days. Of course, the garden caterpillars do not sally
forth on the pine-trees while these are battered by such a gale.

The remarkable part of the business is that the greenhouse caterpillars
do not venture out of their nests either. And yet for them there are no
boughs dangerously shaken, no cold piercing beyond endurance, for it is
not freezing under the glass. What keeps them in can be only the
passage of that wave of depression. On the 15th the storm ceases; and
the barometer remains between 29.6 and 30 in. for the rest of the month
and a good part of February. During this long period there are
magnificent sorties every evening, especially in the greenhouse.

On the 23rd and 24th of February, suddenly the Processionaries stop at
home again, for no apparent reason. Of the six nests under cover, only
two have a few rare caterpillars out on the pine-branches, while
previously, in the case of all six, I used every night to see the
leaves bending under the weight of an innumerable multitude. Warned by
this forecast, I enter in my notes:

“Some deep depression is about to reach us.”

And I have guessed right. Two days later, sure enough, the
meteorological record of the Temps gives me the following information:
a minimum of 29.2 in., coming from the Bay of Biscay on the 22nd,
reaches Algeria on the 23rd and spreads over the Provence coast on the
24th. There is a heavy snowfall at Marseilles on the 25th.


   “The ships,” I read in my paper, “present a curious spectacle, with
    their yards and rigging white. That is how the people of
    Marseilles, little used to such sights, picture Spitzbergen and the
    North Pole.”


Here certainly is the gale which my caterpillars foresaw when they
refused to go out last night and the night before; here is the centre
of disturbance which revealed itself at Sérignan by a violent and icy
north wind on the 25th and the following days. Again I perceive that
the greenhouse caterpillars are alarmed only at the approach of the
wave of atmospheric disturbance. Once the first uneasiness caused by
the depression had abated, they came out again, on the 25th and the
following days, in the midst of the gale, as though nothing
extraordinary were happening.

From the sum of my observations it appears that the Pine Processionary
is eminently sensitive to atmospheric vicissitudes, an excellent
quality, having regard to his way of life in the sharp winter nights.
He foresees the storm which would imperil his excursions.

His capacity for scenting bad weather very soon won the confidence of
the household. When we had to go into Orange to renew our provisions,
it became the rule to consult him the night before; and, according to
his verdict, we went or stayed at home. His oracle never deceived us.
In the same way, simple folk that we were, we used in the old days to
interrogate the Dor-beetle, [20] another doughty nocturnal worker. But,
a little demoralized by imprisonment in a cage and apparently devoid of
any special sensitive apparatus, performing his evolutions, moreover,
in the mild autumn evenings, the celebrated Dung-beetle could never
rival the Pine Caterpillar, who is active during the roughest season of
the year and endowed, as everything would seem to affirm, with organs
quick to perceive the great atmospheric fluctuations.

Rural lore abounds in meteorological forecasts derived from animals.
The Cat, sitting in front of the fire and washing behind her ears with
a saliva-smeared paw, foretells another cold snap; the Cock, crowing at
unusual hours, announces the return of fine weather; the Guinea-fowl,
with her screeching, as of a scythe on the grindstone, points to rain;
the Hen, standing on one leg, her plumage ruffled, her head sunk on her
neck, feels a hard frost coming; the pretty green Tree-frog inflates
his throat like a bladder at the approach of a storm and, according to
the Provençal peasant, says:

“Ploùra, ploùra; it will rain, it will rain!”

This rustic meteorology, the heritage of the centuries, does not show
up so badly beside our scientific meteorology.

Are not we ourselves living barometers? Every veteran complains of his
glorious scars when the weather is about to break. One man, though
unwounded, suffers from insomnia or from bad dreams; another, though a
brain-worker, cannot drag an idea out of his impotent head. Each of us,
in his own way, is tried by the passage of those huge funnels which
form in the atmosphere and hatch the storm.

Could the insect, with its exceptionally delicate organization, escape
this kind of impression? It is unbelievable. The insect, more than any
other creature, should be an animated meteorological instrument, as
truthful in its forecasts, if we knew how to read them, as the lifeless
instruments of our observatories, with their mercury and their catgut.
All, in different degrees, possess a general impressionability
analogous to our own and exercised without the aid of specific organs.
Some, better-gifted because of their mode of life, might well be
furnished with special meteorological apparatus.

The Pine Processionary seems to belong to this number. In his second
costume, when the segments bear on their dorsal faces an elegant red
mosaic, he differs apparently from other caterpillars only by a more
delicate general impressionability, unless this mosaic be endowed with
aptitudes unknown elsewhere. If the nocturnal spinner is still none too
generously equipped, it must be remembered that the season which he
passes in this condition is nearly always clement. The really
formidable nights hardly set in before January. But then, as a
safeguard in his peregrinations, the Pine Processionary cleaves his
back with a series of mouths which yawn open to sample the air from
time to time and to give a warning of the sudden storm.

Until further evidence is forthcoming, therefore, the dorsal slits are,
to my mind, meteorological instruments, barometers influenced by the
main fluctuations of the atmosphere. To go beyond suspicions, though
these are well based, is for me impossible. I lack the equipment
necessary to delve more deeply into the subject. But I have given a
hint. It is for those who are better favoured in the matter of
resources to find the final solution of this interesting problem.



CHAPTER V

THE PINE PROCESSIONARY: THE MOTH


When March comes, the caterpillars reared in domesticity never cease
processioning. Many leave the greenhouse, which remains open; they go
in search of a suitable spot for the approaching metamorphosis. This is
the final exodus, the definite abandonment of the nest and the
pine-tree. The pilgrims are much faded, whitish, with a few russet
hairs on their backs.

On the 20th of March I spend a whole morning watching the evolutions of
a file some three yards in length, containing about a hundred
emigrants. The procession toils grimly along, undulating over the dusty
ground, where it leaves a furrow. Then it breaks into a small number of
groups, which crowd together and remain quiescent save for sudden
oscillations of the hind-quarters. After a halt of varying duration,
these groups resume their march, henceforward forming independent
processions.

They take no settled direction. This one goes forward, that one goes
back; one turns to the left and another to the right. There is no rule
about their marching, no positive goal. One procession, after
describing a loop, retraces its steps. Yet there is a general tendency
towards that wall of the greenhouse which faces the south and reflects
the sun’s rays with added fervour. The sole guide, it would seem, is
the amount of sun which a place obtains; the directions whence the
greatest heat comes are preferred.

After a couple of hours of marching and countermarching, the
fragmentary processions, comprising each a score of caterpillars, reach
the foot of the wall. Here the soil is powdery, very dry, easy to
burrow in, although made somewhat firmer by tufts of grass. The
caterpillar at the head of the row explores with his mandibles, digs a
little, investigates the nature of the ground. The others, trusting
their leader, follow him with docility, making no attempts of their
own. Whatever the foremost decides will be adopted by all. Here, in the
choice of a matter so important as the spot whereat the transformation
shall take place, there is no individual initiative. There is only one
will, the leader’s. There is only one head, so to speak; the procession
may be compared with the chain of segments of an enormous worm.

Finally some spot is recognized as propitious. The leading caterpillar
halts, pushes with his head, digs with his mandibles. The others, still
in a continuous line, arrive one by one and likewise come to a halt.
Then the file breaks up into a swarming heap, in which each of the
caterpillars resumes his liberty. All their backs are joggling
pell-mell; all their heads are plunged into the dust; all their feet
are raking, all their mandibles excavating the soil. The worm has
chopped itself into a gang of independent workers.

An excavation is formed in which, little by little, the caterpillars
bury themselves. For some time to come, the undermined soil cracks and
rises and covers itself with little mole-hills; then all is still. The
caterpillars have descended to a depth of three inches. This is as far
as the roughness of the soil permits them to go. In looser soil, the
excavation would attain a much greater depth. The greenhouse shelf,
supplied with fine sand, has provided me with cocoons placed at a depth
of from eight to twelve inches. I would not assert that the interment
might not be made still lower down. For the most part, the burial is
effected in common, by more or less numerous clusters and at depths
which vary greatly, according to the nature of the soil.

A fortnight later, let us dig at the point where the descent
underground was made. Here we shall find the cocoons assembled in
bunches, cocoons of sorry appearance, soiled as they are with earthy
particles held by silken threads. When stripped of their rough
exterior, they are not without a certain elegance. They are narrow
ellipsoids, pointed at both ends, measuring twenty-five millimetres in
length and nine millimetres [21] in thickness. The silk of which they
are composed is very fine and of a dull white. The fragility of the
walls is remarkable when we have seen the enormous quantity of silk
expended on the construction of the nest.

A prodigious spinner where his winter habitation is concerned, the
caterpillar finds his glands exhausted and is reduced to the strictly
necessary amount when the time comes for making the cocoon. Too poor in
silk, he strengthens his flimsy cell with a facing of earth. With him
it is not the industry of the Bembex [22], who inserts grains of sand
in her silky web and makes a solid casket of the whole; it is a summary
sort of art, devoid of delicacy, which just casually sticks together
the surrounding earthy refuse.

Moreover, if circumstances demand it, the Pine Caterpillar can do
without earth. In the very midst of the nest I have sometimes—very
rarely, it is true—discovered cocoons which were perfectly clean. Not a
scrap of alien matter defiled their fine white silk. I have obtained
similar specimens by placing caterpillars under a bell-glass in a pan
provided only with a few pine-twigs. Better still: an entire
procession, a good-sized one too, gathered at the opportune moment and
enclosed in a large box containing no sand nor any material whatever,
spun its cocoons with no other support than the bare walls. These
exceptions, provoked by circumstances in which the caterpillar is not
free to act according to his wont, does not in any way invalidate the
rule. To prepare for the transformation, the Processionary buries
himself, to the depth of nine inches and more, if the soil permit.

Here a curious problem forces itself upon the observer’s mind. How does
the Moth contrive to ascend from the catacombs into which the
caterpillar has descended? Not in the finery of her perfect state—the
big wings with their delicate scales, the sweeping antenna-plumes—dare
she brave the asperities of the soil, or she would issue thence all
tattered, rumpled and unrecognizable. And this is not the case: far
from it. Moreover, what means can she employ, she so feeble, to break
the crust of earth into which the original dust will have turned after
the slightest of showers?

The Moth appears at the end of July or in August. The burial took place
in March. Rain must have fallen during this lapse of time, rain which
beats down the soil, cements it and leaves it to harden once
evaporation has set in. Never could a Moth, unless attired and equipped
with tools for the purpose, break her way through such an obstacle. She
would perforce require a boring-tool and a costume of extreme
simplicity. Guided by these considerations, I institute a few
experiments which will give me the key to the riddle.

In April I make a copious collection of cocoons. Of these I place ten
or twelve at the bottom of test-tubes of different diameters and, last
of all, I fill the apparatus with sandy soil, sifted and very slightly
moistened. The contents are pressed down, but in moderation, for fear
of injuring the cocoons below. When the month of August comes, the
column of earth, damp at the outset, has set so firmly, thanks to
evaporation, that, when I reverse the test-tube, nothing trickles out.
On the other hand, some cocoons have been kept naked under a metallic
cover. These will teach me what the buried cocoons would not be able to
show. They furnish me, in fact, with records of the greatest interest.
On issuing from the cocoon, the Pine Bombyx has her finery bundled up
and presents the appearance of a cylinder with rounded ends. The wings,
the principal obstacle to underground labour, are pressed against the
breast like narrow scarves; the antennæ, another serious embarrassment,
have not yet unfolded their plumes and are turned back along the Moth’s
sides. The hair, which later forms a dense fleece, is laid flat,
pointing backwards. The legs alone are free, fairly active and endowed
with a certain vigour. Thanks to this arrangement, which does away with
all awkward projections, the ascent through the soil is made possible.

True, every Moth, at the moment of quitting her shell, is this sort of
swathed mummy; but the Pine Bombyx has in addition an exceptional
aptitude rendered necessary by the fact that she hatches under the
ground. While the others, once out of the cocoon, hasten to spread
their wings and are powerless to defer their development, she, by
virtue of an indispensable privilege, remains in her compact and
wrapped-up condition as long as circumstances demand it. Under my
bell-glasses I see some who, though born upon the surface, for
twenty-four hours drag themselves over the sand or cling to the
pine-branches, before untying their sashes and unfurling them as wings.

This delay is evidently essential. To ascend from beneath the earth and
reach the open air, the Moth has to bore a long tunnel, which requires
time. She will take good care not to spread her finery before emerging,
for it would hamper her and would itself be rumpled and badly creased.
Therefore the cylindrical mummy persists until the deliverance is
effected; and, if liberty happen to be acquired before the appointed
moment, the final evolution does not take place until after a lapse of
time in conformity with usage.

We are acquainted with the equipment for emergence, the tight-fitting
jerkin indispensable in a narrow gallery. Now, where is the
boring-tool? The legs, though free, would here be insufficient: they
would scrape the earth laterally, enlarging the diameter of the shaft,
but could not prolong the exit vertically, above the insect’s head.
This tool must be in front.

Pass the tip of your finger over the Moth’s head. You will feel a few
very rough wrinkles. The magnifying-glass shows us more. We find,
between the eyes and higher up, four or five transversal scales, so set
as to overlap one another; they are hard and black and are trimmed
crescent-wise at the ends. The longest and strongest is the uppermost,
which is in the middle of the forehead. There you have the centre-bit
of your boring-tool.

To make our tunnels in granitic rocks we tip our drills with diamond
points. For a similar task the Bombyx, a living drill, wears implanted
on her forehead a row of crescents, hard and durable as steel, a
regular twist-bit. Without suspecting its use, Réaumur was perfectly
aware of this marvellous implement, which he called scaly stairs:

“What does it profit this Moth,” he asks, “that she should thus have
the front of her head formed like scaly stairs? That is just what I do
not know.”

My test-tubes, learned master, will tell us. By good fortune, of the
numerous Moths ascending from the bottom of my apparatus through a
column of sand solidified by the evaporation of the original moisture,
some are making their way upwards against the side of the tube,
enabling me to follow their manœuvres. I see them raising their
cylindrical bodies, butting with their heads, jerking now in one
direction, now in another. The nature of their task is obvious. The
centre-bits, with an alternating movement, are boring into the
agglutinated sand. The powdery wreckage trickles down from overhead and
is at once thrust backward by the legs. A little space forms at the top
of the vault; and the Moth moves so much nearer to the surface. By the
following day, the whole column, ten inches in height, will be
perforated with a straight, perpendicular shaft.

Shall we now form an idea of the total work performed? Let us turn the
test-tube upside down. The contents, as I have said, will not fall out,
for they have set into a block; but from the tunnels bored by the Moth
trickles all the sand crumbled by the crescents of the drill. The
result is a cylindrical gallery, of the width of a lead-pencil, very
cleanly cut and reaching to the bottom of the solid mass.

Are you satisfied, my master? Do you now perceive the great utility of
the scaly stairs? Would you not say that we have here a magnificent
example of an instrument superlatively fitted for a definite task? I
share this opinion, for I think, with you, that a sovereign Reason has
in all things coordinated the means and the end.

But let me tell you: we are called old-fashioned, you and I; with our
conception of a world ruled by an Intelligence, we are quite out of the
swim. Order, balance, harmony: that is all silly nonsense. The universe
is a fortuitous arrangement in the chaos of the possible. What is white
might as easily be black, what is round might be angular, what is
regular might be shapeless and harmony might just as well be discord.
Chance has decided all things.

Yes, we are a pair of prejudiced old fogeys when we linger with a
certain fondness over the marvels of perfection. Who troubles about
these futilities nowadays? So-called serious science, the science which
spells honour, profit and renown, consists in slicing your animal with
very costly instruments into tiny circular sections. My housekeeper
does as much with a bunch of carrots, with no higher pretension than to
concoct a modest dish, which is not an invariable success. In the
problem of life are we more successful when we have split a fibre into
four and cut a cell into shavings? It hardly seems so. The riddle is as
dark as ever. Ah, how much better is your method, my dear master; above
all, how much loftier your philosophy, how much more wholesome and
invigorating!

Here at last is the Moth at the surface. With the deliberate slowness
demanded by so delicate an operation, she spreads her bunched wings,
extends her antennæ and puffs out her fleece. Her costume is a modest
one: upper wings grey, striped with a few crinkly brown streaks;
under-wings white; thorax covered with thick grey fur; abdomen clad in
bright-russet velvet. The last segment has a pale-gold sheen. At first
sight it appears bare. It is not, however; but, in place of hairs like
those of the other segments, it has, on its dorsal surface, scales so
well assembled and so close together that the whole seems to form a
continuous block, like a nugget.

Let us touch this trinket with the point of a needle. However gently we
rub, a multitude of scales come off and flutter at the least breath,
shining like mica spangles. Their concave form, their shape, an
elongated oval, their colouring, white in the lower half but reddish
gold in the upper, give them, if we allow for the difference in size, a
certain resemblance to the scales surrounding the heads of some of the
centaury tribe. Such is the golden fleece of which the mother will
despoil herself in order to cover the cylinder of her eggs. The nugget
of her hind-quarters, exfoliated spangle by spangle, will form a roof
for the germs arranged like the grain in a corn-cob.

I was anxious to watch the actual placing of these pretty tiles, which
are fixed at the pale end with a speck of cement, leaving the coloured
end free. Circumstances did not favour me. Inactive all day, motionless
on some needle of the lower branches, the Moth, whose life is very
short, moves only in the darkness of the night. Both her mating and
egg-laying are nocturnal. On the morrow, all is finished: the Bombyx
has lived. Under these conditions, it was impossible, by the doubtful
beams of a lantern, to follow satisfactorily the labour of the mother
on the pine-trees in the garden.

I was no more fortunate with the captives in my bell-glasses. A few did
lay their eggs, but always at a very advanced hour of the night, an
hour which found my vigilance at fault. The light of a candle and eyes
heavy with sleep were of little avail when it came to analysing the
subtle operations of the mother as she puts her scales in place. We
will say nothing of the little that was imperfectly seen.

Let us close with a few words of sylvicultural practice. The Pine
Processionary is a voracious caterpillar who, while respecting the
terminal bud, protected by its scales and its resinous varnish,
completely denudes the bough and imperils the tree by leaving it bald.
The green pine-needles, that mane in which the vegetable vigour of the
tree resides, are shorn to the roots. How are we to remedy this?

When consulted on the subject, the forest-ranger of my parish told me
that the custom is to go from tree to tree with pruning-shears fitted
on a long pole and to cut down the nests, afterwards burning them. The
method is a troublesome one, for the silken purses are often at
considerable heights. Moreover, it is not without danger. Attacked by
the hairy dust, the destroyers soon experience intolerable discomfort,
a torture of irritation which makes them refuse to continue the work.
To my thinking it would be better to operate before the appearance of
the nests.

The Pine Bombyx is a very bad flyer. Incapable of soaring, almost like
the Silk-moth, she flutters about and blunders to earth again; and her
best efforts barely succeed in bringing her to the lower branches,
which almost drag along the ground. Here are deposited the cylinders of
eggs, at a height of six feet at most. It is the young caterpillars
who, from one provisional encampment to another, gradually ascend,
attaining, stage by stage, the summits upon which they weave their
final dwellings. Once we grasp this peculiarity, the rest is plain
sailing.

In August we inspect the lower foliage of the tree: an easy
examination, for it is carried on no higher than our heads. Towards the
far end of the twigs it is easy to espy the Bombyx’ eggs, packed into
cylinders that resemble scaly catkins. Their size and their whitish
colour make them show up amid the sombre green. Gathered with the
double pine-needle that bears them, these cylinders are crushed under
foot, a summary fashion of stamping out an evil before it spreads.

This I have done in the case of the few pine-trees in my enclosure. And
the same might be done in the wider forest expanses and more especially
in parks and gardens, where symmetrical foliation is one of the great
beauties of the tree. I will add that it is wise to prune every bough
that droops to earth and to keep the foot of the conifer bare to a
height of six feet or so. In the absence of these lower stairs, the
only ones that the Bombyx with her clumsy flight can reach, she will
not be able to populate the tree.



CHAPTER VI

THE PINE PROCESSIONARY: THE STINGING POWER


The Pine Processionary has three costumes: that of infancy, a scanty,
ragged fleece, a mixture of black and white; that of middle age, the
richest of the three, when the segments deck themselves on their dorsal
surface with golden tufts and a mosaic of bare patches, scarlet in
colour; and that of maturity, when the rings are cleft by slits which
one by one open and close their thick lips, champing and grinding their
bristling russet beards and chewing them into little pellets, which are
thrown out on the creature’s sides when the bottom of the pocket swells
up like a tumour.

When wearing this last costume, the caterpillar is very disagreeable to
handle, or even to observe at close quarters. I happened, quite
unexpectedly, to learn this more thoroughly than I wished.

After unsuspectingly passing a whole morning with my insects, stooping
over them, magnifying-glass in hand, to examine the working of their
slits, I found my forehead and eyelids suffering with redness for
twenty-four hours and afflicted with an itching even more painful and
persistent than that produced by the sting of a nettle. On seeing me
come down to dinner in this sad plight, with my eyes reddened and
swollen and my face unrecognizable, the family anxiously enquired what
had happened to me and were not reassured until I told them of my
mishap.

I unhesitatingly attribute my painful experience to the red hairs
ground to powder and collected into flakes. My breath sought them out
in the open pockets and carried them to my face, which was very near.
The unthinking intervention of my hands, which now and again sought to
ease the discomfort, merely aggravated the ill by spreading the
irritating dust.

No, the search for truth on the back of the Processionary is not all
sunshine. It was only after a night’s rest that I found myself pretty
well recovered, the incident having no further ill effects. Let us
continue, however. It is well to substitute premeditated experiments
for chance facts.

The little pockets of which the dorsal slits form the entrance are
encumbered, as I have said, with hairy refuse, either scattered or
gathered into flakes. With the point of a paint-brush I collect, when
they gape open, a little of their contents and rub it on my wrist or on
the inside of my fore-arm.

I have not long to wait for the result. Soon the skin turns red and is
covered with pale lenticular swellings, similar to those produced by a
nettle-sting. Without being very sharp, the pain was extremely
unpleasant. By the following day, itching, redness and lenticular
swellings had all disappeared. This is the usual sequence of events;
but let me not omit to say that the experiment does not always succeed.
The efficacy of the fluffy dust appears subject to great variations.

There have been occasions when I have rubbed myself with the whole
caterpillar, or with his cast skin, or with the broken hairs gathered
on a paint-brush, without producing any unpleasant results. The
irritant dust seems to vary in quality according to certain
circumstances which I have not been able to discover.

From my various tests it is evident that the discomfort is caused by
the delicate hairs which the lips of the dorsal mouths, gaping and
closing again, never cease grinding, to the detriment of their beards
and moustaches. The edges of these slits, as their bristles rub off,
furnish the stinging dust.

Having established this fact, let us proceed to more serious
experiments. In the middle of March, when the Processionaries for the
most part have migrated underground, I decide to open a few nests, as I
wish to collect their last inhabitants for the purpose of my
investigations. Without taking any precautions, my fingers tug at the
silken dwelling, which is made of solid stuff; they tear it into
shreds, search it through and through, turn it inside out and back
again.

Once more and this time in a more serious fashion, I am the victim of
my unthinking enthusiasm. Hardly is the operation completed, when the
tips of my fingers begin to hurt in good earnest, especially in the
more delicate part protected by the edge of the nail. The feeling is
like the sharp pain of a sore that is beginning to fester. All the rest
of the day and all through the night, the pain persists, troublesome
enough to rob me of my sleep. It does not quiet down until the
following day, after twenty-four hours of petty torment.

How did this new misadventure befall me? I had not handled the
caterpillars: indeed, there were very few of them in the nest at the
time. I had come upon no shed skins, for the moults do not take place
inside the silken purse. When the moment has come to doff the second
costume, that of the red mosaic, the caterpillars cluster outside, on
the dome of their dwelling, and there leave in a single heap their old
clothes entangled with bits of silk. What is left to explain the
unpleasant consequences to which the handling of the nest exposes us?

The broken red bristles are left, the fallen hairs forming a dust that
is invisible without a very careful examination. For a long time the
Processionaries crawl and swarm about the nest; they pass to and fro,
penetrating the thickness of the wall when they go to the pastures and
when they return to their dormitory. Whether motionless or on the move,
they are constantly opening and closing their apparatus of information,
the dorsal mouths. At the moment of closing, the lips of these slits,
rolling on each other like the cylinders of a flattening-mill, catch
hold of the fluff near them, tear it out and break it into fragments
which the bottom of the pocket, presently reascending, shoots outside.

Thus myriads of irritant particles are disseminated and subtly
introduced into every part of the nest. The shirt of Nessus burnt the
veins of whoso wore it; the silk of the Processionary, another poisoned
fabric, sets on fire the fingers that handle it.

The loathsome hairs long retain their virulence. I was once sorting out
some handfuls of cocoons, many of which were diseased. As the hardness
of the contents was usually an indication that something was wrong, I
tore open the doubtful cocoons with my fingers, in order to save the
non-contaminated chrysalids. My sorting was rewarded with the same kind
of pain, especially under the edges of the nails, as I had already
suffered when tearing the nests.

The cause of the irritation on this occasion was sometimes the dry skin
discarded by the Processionary on becoming a chrysalis and sometimes
the shrivelled caterpillar turned into a sort of chalky cylinder
through the invasion of the malignant fungus. Six months later, these
wretched cocoons were still capable of producing redness and
irritation.

Examined under the microscope, the russet hairs, the cause of the
itching, are stiff rods, very sharp at either end and armed with barbs
along the upper half. Their structure has absolutely nothing in common
with nettle-hairs, those tapering phials whose hard point snaps off,
pouring an irritant fluid into the tiny wound.

The plant from whose Latin name, Urtica, we derive the word urtication
borrowed the design of its weapon from the fangs of the venomous
serpents; it obtains its effect, not by the wound, but by the poison
introduced into the wound. The Processionary employs a different
method. The hairs, which have naught resembling the ampullary reservoir
of the nettle-hairs, must be poisoned on the surface, like the assegais
of the Kafirs and Zulus.

Do they really penetrate the epidermis? Are they like the savage’s
javelin, which cannot be extracted once it has gone in? With their
barbs, do they enter all the more deeply because of the quivering of
the outraged flesh? There is no ground for believing anything of the
kind. In vain do I scrutinize the injured spot through the
magnifying-glass; I can see no sign of the implanted dart. Neither
could Réaumur, when an encounter with the Oak Processionary set him
scratching himself. He had his suspicions, but could state nothing
definitely.

No; despite their sharp points and their barbs, which make them, under
the microscope, such formidable spears, the Processionary’s russet
hairs are not darts designed to imbed themselves in the skin and to
provoke irritation by pricking.

Many caterpillars, all most inoffensive, have a coat of bristles which,
under the microscope, resolve themselves into barbed javelins, quite
harmless in spite of their threatening aspect. Let me mention a couple
of these peaceable halberdiers.

Early in spring, we see, crossing the paths, a briskly-moving
caterpillar who inspires repugnance by his ferocious hairiness, which
ripples like ripe corn. The ancient naturalists, with their artless and
picturesque nomenclature, called him the Hedgehog. The term is worthy
of the creature, which, in the moment of danger, rolls itself up like a
Hedgehog, presenting its spiny armour on all sides to the enemy. On its
back is a dense mixture of black hairs and hairs of ashen-gray; while
on the sides and fore-part of the body is a stiff mane of bright
russet. Black, grey or russet, all this fierce-looking coat is heavily
barbed.

One hesitates to touch this horror with the finger-tips. Still,
encouraged by my example, seven-year-old Paul, with his tender child’s
skin, gathers handfuls of the repulsive insect with no more
apprehension than if he were picking a bunch of violets. He fills his
boxes with it; he rears it on elm-leaves and handles it daily, for he
knows that from this frightful creature he will one day obtain a superb
Moth (Chelonia caja, Linn.), clad in scarlet velvet, with the lower
wings red and the upper white, sprinkled with brown spots.

What resulted from the child’s familiarity with the shaggy creature?
Not even a trace of itching on his delicate skin. I do not speak of
mine, which is tanned by the years.

In the osier-beds of our local stream, the rushing Aygues, a thorny
shrub abounds which, at the advent of autumn, is covered with an
infinity of very sour red berries. Its crabbed boughs, which bear but
little verdure, are hidden under their clusters of vermilion balls. It
is the sallow thorn or sea buckthorn (Hippophaë rhamnoides).

In April, a very hairy but rather pretty caterpillar lives at the
expense of this shrub’s budding leaves. He has on his back five dense
tufts of hair, set side by side and arranged like the bristles of a
brush, tufts deep-black in the centre and white at the edges. He waves
two divergent plumes in front of him and sports a third on his crupper,
like a feathery tail. These three are black hair-pencils of extreme
delicacy.

His greyish Moth, flattened motionless on the bark, stretches his long
fore-legs, one against the other, in front of him. You would take them,
at a first glance, for antennae of exaggerated proportions. This pose
of the extended limbs has won the insect the scientific label of
Orgyia, arm’s length; and also the vulgar and more expressive
denomination of Patte étendue, or outstretched paw.

Little Paul has not failed, with my aid, to rear the pretty bearer of
the tufts and brushes. How many times, with his sensitive finger, has
he not stroked the creature’s furry costume? He found it softer than
velvet. And yet, enlarged under the microscope, the caterpillar’s hairs
are horrible barbed spears, no less menacing than those of the
Processionary. The resemblance goes no farther: handled without
precautions, the tufted caterpillar does not provoke even a simple
rash. Nothing could be more harmless than his coat.

It is evident, then, that the cause of the irritation lies elsewhere
than in the barbs. If the barbed bristles were enough to poison the
fingers, most hairy caterpillars would be dangerous, for nearly all
have spiny bristles. We find, on the contrary, that virulence is
bestowed upon a very small number, which are not distinguished from the
rest by any special structure of the hair.

That the barbs have a part to play, that of fixing the irritant atom
upon the epidermis, of keeping it anchored in its place, is, after all,
possible; but the shooting pains cannot by any means be caused by the
mere prick of so delicate a harpoon.

Much less slender, the hairs clustered into pads on the prickly pears
are ferociously barbed. Woe to the fingers that handle this kind of
velvet too confidently! At the least touch they are pierced with
harpoons whose extraction involves a severe tax upon our patience.
Other inconvenience there is little or none, for the action of the barb
is in this case purely mechanical. Supposing—a very doubtful thing—that
the Processionary’s hairs could penetrate our skin, they would act
likewise, only with less effect, if they had merely their sharp points
and their barbs. What then do they possess in addition?

They must have, not inside them, like the hairs of the nettle, but
outside, on the surface, an irritant agent; they must be coated with a
poisonous mixture, which makes them act by simple contact.

Let us remove this virus, by means of a solvent; and the
Processionary’s darts, reduced to their insignificant mechanical
action, will be harmless. The solvent, on the other hand, rid of all
hairs by filtration, will be charged with the irritant element, which
we shall be able to test without the agency of the hairs. Isolated and
concentrated, the stinging element, far from losing by this treatment,
ought to gain in virulence. So reflection tells us.

The solvents tried are confined to three: water, spirits of wine and
sulphuric ether. I employ the latter by preference, although the other
two, spirits of wine especially, have yielded satisfactory results. To
simplify the experiment, instead of submitting to the action of the
solvent the entire caterpillar, who would complicate the extract with
his fats and his nutritive juices, I prefer to employ the cast skin
alone.

I therefore collect, on the one hand, the heap of dry skins which the
moult of the second phase has left on the dome of the silken dwelling
and, on the other hand, the skins which the caterpillars have rejected
in their cocoons before becoming chrysalids; and I leave the two lots
to infuse, separately, in sulphuric ether for twenty-four hours. The
infusion is colourless. The liquid, carefully filtered, is exposed to
spontaneous evaporation; and the skins are rinsed with ether in the
filter, several times over.

There are now two tests to be made: one with the skins and one with the
product of maceration. The first is as conclusive as can be. Hairy as
in the normal state and perfectly dried, the skins of both lots,
drained by the ether, produce not the slightest effect, although I rub
myself with them, without the least caution, at the juncture of the
fingers, a spot very sensitive to stinging.

The hairs are the same as before the action of the solvent: they have
lost none of their barbs, of their javelin-points; and yet they are
ineffectual. They produce no pain or inconvenience whatever. Deprived
of their toxic smearing, these thousands of darts become so much
harmless velvet. The Hedgehog Caterpillar and the Brush Caterpillar are
not more inoffensive.

The second test is more positive and so conclusive in its painful
effects that one hardly likes to try it a second time. When the
ethereal infusion is reduced by spontaneous evaporation to a few drops,
I soak in it a slip of blotting-paper folded in four, so as to form a
square measuring something over an inch. Too unsuspecting of my
product, I do things on a lavish scale, both as regards the superficial
area of my poor epidermis and the quantity of the virus. To any one who
might wish to renew the investigation I should recommend a less
generous dose. Lastly, the square of paper, that novel sort of
mustard-plaster, is applied to the under surface of the fore-arm. A
thin waterproof sheeting covers it, to prevent it from drying too
rapidly; and a bandage holds it in place.

For the space of ten hours, I feel nothing; then I experience an
increasing itch and a burning sensation acute enough to keep me awake
for the greater part of the night. Next day, after twenty-four hours of
contact, the poultice is removed. A red mark, slightly swollen and very
clearly outlined, occupies the square which the poisoned paper covered.

The skin feels sore, as though it had been cauterized, and looks as
rough as shagreen. From each of its tiny pustules trickles a drop of
serous fluid, which hardens into a substance similar in colour to
gum-arabic. This oozing continues for a couple of days and more. Then
the inflammation abates; the pain, hitherto very trying, quiets down;
the skin dries and comes off in little flakes. All is over, except the
red mark, which remains for a long time, so tenacious in its effects is
this extract of Processionary. Three weeks after the experiment, the
little square on the fore-arm subjected to the poison is still
discoloured.

For thus branding one’s self, does one at least obtain some small
reward? Yes. A little truth is the balm spread upon the wound; and
indeed truth is a sovran balm. It will come presently to solace us for
much greater sufferings.

For the moment, this painful experiment shows us that the irritation
has not as its primary cause the hairiness of the Processionary. Here
is no hair, no barb, no dart. All of that has been retained by the
filter. We have nothing now but a poisonous agent extracted by the
solvent, the ether. This irritant element recalls, to a certain extent,
that of cantharides, which acts by simple contact. My square of
poisoned blotting-paper was a sort of plaster, which, instead of
raising the epidermis in great blisters, makes it bristle with tiny
pustules.

The part played by the barbed hairs, those atoms which the least
movement of the air disseminates in all directions, is confined to
conveying to our face and hands the irritant substance in which they
are impregnated. Their barbs hold them in place and thus permit the
virus to act. It is even probable that, by means of slight scratches
which would otherwise pass unnoticed, they assist the action of the
stinging fluid.

Shortly after handling the Processionaries, a delicate epidermis
becomes tumefied, red and painful. Without being immediate, the action
of the caterpillar is prompt. The extract made with ether, on the other
hand, causes pain and rubefaction only after a longish interval. What
does it need to produce more rapid ulceration? To all appearances, the
action of the hairs.

The direct stinging caused by the caterpillar is nothing like so
serious as that produced by the ethereal extract concentrated in a few
drops. Never before, in my most painful misadventures, whether with the
silken purses or their inhabitants, have I seen my skin covered with
serous pustules and peeling off in flakes. This time it is a veritable
sore, anything but pleasing to the eye.

The aggravation is easily explained. I soaked in the ether some fifty
discarded skins. The few drops which remained after the evaporation and
which were absorbed by the square of blotting-paper represented,
therefore, the virulence of a single insect fifty times increased. My
little blistering-plaster was equivalent to the contact of fifty
caterpillars at the same spot. There is no doubt that, if we left them
to steep in considerable numbers, we should obtain extracts of really
formidable strength. It is quite possible that medical science will one
day make good use of this powerful counter-irritant, which is utterly
different from cantharides.

Whether voluntary victims of our curiosity, which, while affording no
other satisfaction than that of knowledge, exposes us to an intolerable
itch, or sufferers through an accident, what can we do to give a little
relief to the irritation caused by the Processionary? It is good to
know the origin of the evil, but it would be better to apply a remedy.

One day, with both hands sore from the prolonged examination of a nest,
I try without success lotions of alcohol, glycerine, oil and soapsuds.
Nothing does any good. I then remember a palliative employed by Réaumur
against the sting of the Oak Processionary. Without telling us how he
came to know of the strange specific, the master rubbed himself with
parsley and felt a good deal the better for it. He adds that any other
leaf would probably assuage the irritation in the same way.

This is a fitting occasion for reopening the subject. Here, in a corner
of the garden, is parsley, green and abundant as one could wish. What
other plant can we compare with it? I choose the purslain, the
spontaneous guest of my vegetable-beds. Mucilaginous and fleshy as it
is, it readily crushes, yielding an emollient liniment. I rub one hand
with parsley and the other with purslain, pressing hard enough to
reduce the leaves to a paste. The result deserves attention.

With the parsley, the burning is a little less acute, it is true, but,
though relieved, it persists for a long time yet and continues
troublesome. With the purslain, the petty torture ceases almost at once
and so completely that I no longer notice it. My nostrum possesses
incontestable virtues. I recommend it quietly, without blatant
advertisement, to any one who may be persecuted by the Processionary.
Foresters, in their war upon caterpillars’ nests, should find great
relief from it.

I have also obtained good results with the leaves of the tomato and the
lettuce; and, without pursuing this botanical survey further, I remain
convinced, with Réaumur, that any tender juicy foliage would possess a
certain efficacy.

As for the mode of action of this specific, I admit that I do not
understand it, any more than I can perceive the mode of action of the
caterpillar’s virus. Molière’s medical student explained the soporific
properties of opium by saying:

“Quia est in eo virtus dormitava cujus est proprietas sensus
assoupire.”

Let us say likewise: the crushed herb calms the burning itch because it
possesses a calming virtue whose property is to assuage itching.

The quip is a good deal more philosophical than it looks. What do we
know of our remedies or of anything? We perceive effects, but we cannot
get back to their causes.

In my village and for some distance around it, there is a popular
belief that to relieve the pain of a Wasp’s or Bee’s sting all that we
need do is to rub the part stung with three sorts of herbs. Take, they
say, three kinds of herbs, the first that come to hand, make them into
a bunch and rub hard. The prescription, by all accounts, is infallible.

I thought at first that this was one of those therapeutic absurdities
which have their birth in rustic imaginations. After making a trial, I
admit that what sounds like a nonsensical remedy sometimes has
something genuine about it. Friction with three kinds of herbs does
actually deaden the sting of the Wasp or Bee.

I hasten to add that the same success is achieved with a single herb;
and so the result agrees with what the parsley and purslain have taught
us in respect of the irritation caused by the Processionary.

Why three herbs when one is enough? Three is the preeminently lucky
number; it smacks of witchcraft, which is far from detracting from the
virtues of the unguent. All rustic medicine has a touch of magic about
it; and there is merit in doing things by threes.

Perhaps the specific of the three herbs may even date back to the
materia medica of antiquity. Dioscorides recommends τρίφυλλον: it is,
he states, good for the bite of venomous serpents. To determine this
celebrated three-leaved plant exactly would not be easy. Is it a common
clover? The psoralea, with its pitchy odour? The menyanthes, or
uck-bean, that inmate of the chilly peat-bogs? The oxalis, the
wood-sorrel of the country-side? We cannot tell for certain. The botany
of those days was innocent of the descriptive conscientiousness of
ours. The plant which acted as a poison-antidote grouped its leaves by
threes. That is its essential characteristic.

Again the cabalistic number, essential to medical virtues as conceived
by the first healers. The peasant, a tenacious conservative, has
preserved the ancient remedy, but, by a happy inspiration, has changed
the three original leaves into three different herbs; he has elaborated
the τρίφυλλον into the threefold foliage which he crushes on the Bee’s
sting. I seem to perceive a certain relation between these artless ways
and the crushing of parsley as described by Réaumur.



CHAPTER VII

THE ARBUTUS CATERPILLAR


I have not found many species of urticating caterpillars in the small
corner of my investigations. I know of two only: the Pine Caterpillar
and the Arbutus Caterpillar. The latter belongs to the genus Liparis.
His Moth, who is a glorious snowy white, with the last rings of the
abdomen bright russet, is very like Liparis auriflua, Fab., from whom
she differs not only in size—she is smaller—but, above all, in the
field of operations selected by her caterpillar. Is the species
classified in our lists? I do not know; and really it is hardly worth
while to enquire. What does a Latin name matter, when one cannot
mistake the insect? I shall be sparing of detail concerning the Arbutus
Caterpillar, for he is far less interesting in his habits than the Pine
Processionary. Only his ravages and his poison deserve serious
attention.

On the Sérignan hills, sunny heights upon which the Mediterranean
vegetation comes to an end, the arbutus, or strawberry-tree, abounds: a
magnificent shrub, with lustrous evergreen foliage, vermilion fruit,
round and fleshy as strawberries, and hanging clusters of little white
bells resembling those of the lily of the valley. When the frosts come
at the approach of December, nothing could be more charming than the
arbutus, decking its gay verdure with both fruits and flowers, with
coral balls and plump little bells. Alone of our flora, it combines the
flowering of to-day with the ripening of yesterday.

Then the bright-red raspberries—the darbouses, as we call them
here—beloved by the Blackbird, grow soft and sweet to the palate. The
housewives pluck them and make them into preserves that are not without
merit. As for the shrub itself, when the season for cutting has come,
it is not, despite its beauty, respected by the woodman. It serves,
like any trivial brushwood, in the making of faggots for heating ovens.
Frequently, too, the showy arbutus is ravaged by a caterpillar yet more
to be dreaded than the woodcutter. After this glutton has been at it,
it could not look more desolate had it been scorched and blackened by
fire.

The Moth, a pretty little, snow-white Bombyx, with superb antennary
plumes and a cotton-wool tippet on her thorax, lays her eggs on a leaf
of the arbutus and, in so doing, starts the evil.

You see a little cushion with pointed ends, rather less than an inch in
length; a white eiderdown, tinged with russet, thick, very soft and
formed of hairs fixed with a little gum by the end that points towards
the upper extremity of the leaf. The eggs are sunk in the thickness of
this soft shelter. They possess a metallic sheen and look like so many
nickel granules.

Hatching takes place in September. The first meals are made at the
expense of the native leaf; the later ones at the expense of the leaves
all around. One surface only is nibbled, usually the upper; the other
remains intact, trellised by the network of veins, which are too horny
for the new-born grubs.

The consumption of leaves is effected with scrupulous economy. Instead
of grazing at hazard and using up the pasturage at the dictates of
individual caprice, the flock progresses gradually from the base to the
tip of the leaf, with all heads ranged in a frontal attack, almost in a
straight line. Not a bite is taken beyond this line, until all that
lies on this side of it is eaten up.

As it advances, the flock throws a few threads across the denuded
portion, where nothing remains but the veins and the epidermis of the
opposite surface. Thus is woven a gossamer veil serving as a shelter
from the fierce rays of the sun and as the parachute which is essential
to these weaklings, whom a puff of wind would carry away.

As the result of a more rapid desiccation on the ravaged surface, the
leaf soon begins to curl of its own accord, curving into a gondola
which is covered by a continuous awning stretched from end to end. The
herbage is then exhausted. The flock abandons it and begins again
elsewhere in the near neighbourhood.

After various temporary pastures of this kind, in November, when the
cold weather is at hand, the caterpillars settle permanently at the end
of a bough. Nibbled one by one on their upper surfaces, the leaves of
the terminal bunch draw close to their neighbours, which, excoriated in
their turn, do the same, until the whole forms a bundle, which looks as
if it had been scorched, lashed together with magnificent white silk.
This is the winter habitation, whence the family, still very feeble,
will not issue until the fine weather returns.

The assembling of this leafy framework is not due to any special
industry on the caterpillars’ part; they do not stretch their threads
from leaf to leaf and then, by pulling at these ropes, bring the
various pieces of the structure into contact. It is merely the result
of desiccation on the nibbled surfaces. Fixed cables, it is true,
solidly bind together the leaves brought close to one another by the
contraction due to their aridity; but they do not in any way play the
part of a motive mechanism in the work of the assemblage.

No hauling-ropes are here, no capstans to move the timbers. The feeble
creatures would be incapable of such effort. The thing happens of
itself. Sometimes a floating thread, the plaything of the air, enlaces
some adjacent leaf. This chance footbridge tempts the explorers, who
hasten to strip the accidental prize; and, without other labour, yet
one more leaf bends of its own accord and is added to the enclosure.
For the most part, the house is built by eating; a lodging is procured
by dint of banqueting.

A comfortable house, tightly closed and well-caulked, proof against
rain and snow. We, to guard ourselves against draughts, put sand-bags
against the cracks of our doors and windows; the extravagant little
Arbutus Caterpillar applies pipings of silk-velvet to his shutters.
Things should be cosy inside, however damp the fog. In bad weather, the
rain drips into my house. The leaf-dwelling knows nothing of such
troubles, so true is it that animals often enjoy advantages which
relegate human industry to the second rank.

In this shelter of silk and foliage, the worst three or four months of
the year are passed in a state of complete abstinence. No outings; not
a bite of food. In March, this torpor ceases; and the recluses, those
starving bellies, shift their quarters.

The community now splits up into squads, which spread themselves anyhow
over the adjacent verdure. This is the period of serious devastation.
The caterpillars no longer confine themselves to nibbling one surface
of the leaf; their keen appetites demand the whole of it, down to the
stalk. And now, stage by stage, halt by halt, the arbutus is shorn
bare.

The vagabonds do not return to their winter dwelling, which has become
too closely cramped. They reassemble in groups and weave, here, there
and everywhere, shapeless tents, temporary huts, abandoned for others
as the pasturage round about becomes exhausted. The denuded boughs, to
all seeming ravaged by fire, take on the look of squalid drying-grounds
hung with rags.

In June, having acquired their full growth, the caterpillars leave the
arbutus-tree, descend to earth and spin themselves, amid the dead
leaves, a niggardly cocoon, in which the insect’s hairs to some extent
supplement its silk. A month later, the Bombyx appears.

In his final dimensions, the caterpillar measures nearly an inch and a
quarter in length. His costume does not lack richness or originality: a
black skin with a double row of orange specks on the back; long grey
hairs arranged in bunches; short, snow-white tufts on the sides; and a
couple of brown-velvet protuberances on the first two rings of the
abdomen and also on the last ring but one.

The most remarkable feature, however, consists of two tiny craters,
always open wide; two cunningly fashioned goblets which might have been
wrought from a drop of red sealing-wax. The sixth and seventh segments
of the abdomen are the only ones that bear these vermilion goblets,
placed in the middle of the back. I do not know the function of these
little cups. Perhaps they should be regarded as organs of information,
similar to the Pine Processionary’s dorsal mouths.

The Arbutus Caterpillar is much dreaded in the village. Woodcutters,
faggot-binders, brushwood-gatherers, all are unanimous in reviling him.
They have such a painfully vivid memory of the irritation that, when I
listen to them, I can hardly repress a movement of the shoulders to
relieve the imaginary itching in the middle of my back. I seem to feel
the arbutus-faggot, laden with its glowing rags, rubbing my bare skin.

It is, it appears, a disagreeable job to cut down the shrub alive with
caterpillars during the hottest part of the day and to shake, under the
blows of the axe, that sort of upas-tree, shedding poison in its shade.
As for me, I have no complaint to make of my relations with the ravager
of the arbutus. I have very often handled him; I have applied his fur
to the tips of my fingers, my neck and even my face, for hours at a
time; I have ripped up the nests to extract their populations for the
purpose of my researches; but I have never been inconvenienced. Save in
exceptional circumstances, the approach of the moult perhaps, this
would need a skin less tough than mine.

The thin skin of a child does not enjoy the same immunity, as witness
little Paul, who, having helped me to empty some nests and to collect
the inhabitants with my forceps, was for hours scratching his neck,
which was dotted with red wheals. My ingenuous assistant was proud of
his sufferings in the cause of science, which resulted from
heedlessness and also perhaps from bravado. In twenty-four hours, the
trouble disappeared, without leaving any serious consequences.

All this hardly tallies with the painful experiences of which the
woodcutters talk. Do they exaggerate? That is hardly credible; they are
so unanimous. Then something must have been lacking in my experiments:
the propitious moment apparently, the proper degree of maturity in the
caterpillar, the high temperature which aggravates the poison.

To show itself in its full severity, the urtication demands the
cooperation of certain undefined circumstances; and this cooperation
was wanting. Chance perhaps will one day teach me more than I want to
know; I shall be attacked in the manner familiar to the woodcutters and
shall pass a night in torment, tossing and turning as though on a bed
of live coals.

What the direct contact of the caterpillar did not teach me the
artifices of chemistry will demonstrate with a violence which I was far
from expecting. I treat the caterpillar with ether, just as I treated
the slough of the Pine Processionary. The number of the creatures taken
for the infusion—they are pretty small as yet, are scarcely half the
size which they will attain when mature—is about a hundred. After a
couple of days’ maceration, I filter the liquid and leave it to
evaporate freely. With the few drops that remain I soak a square of
blotting-paper folded in four and apply it to the inner surface of my
fore-arm, with a thin rubber sheet and a bandage. It is an exact
repetition of what I did with the Pine Processionary.

Applied in the morning, the blister hardly takes effect until the
following night. Then by degrees the irritation becomes unendurable;
and the burning sensation is so acute that I am tormented every moment
with the desire to tear off the bandage. However, I hold out, but at
the cost of a sleepless, feverish night.

How well I now understand what the woodcutters tell me! I had less than
a square inch of skin subjected to the torture. What would it be if I
had my back, shoulders, neck, face and arms tormented in this fashion?
I pity you with all my heart, you labourers who are troubled by the
hateful creature.

On the morrow, the infernal paper is removed. The skin is red and
swollen, covered with tiny pimples whence ooze drops of serous fluid.
For five days the itching persists, with a sharp, burning pain, and the
running from the pimples continues. Then the dead skin dries and comes
off in scabs. All is over, save the redness, which is still perceptible
a month later.

The demonstration is accomplished; the Arbutus Caterpillar, capable as
he is of producing, under certain conditions, the same effects which I
obtain by artificial means, fully deserves his odious reputation.



CHAPTER VIII

AN INSECT VIRUS


One step forward has been taken, but only a very little one as yet, in
the problem of the stinging caterpillars. The drenching with ether
teaches us that hairiness plays a very secondary part in the matter.
With its dust of broken bristles, which the least breath wafts in all
directions, it bothers us by depositing and fixing its irritant coating
upon us; but this virus does not originate in the creature’s fleece; it
comes from elsewhere. What is the source of it?

I will enter into a few details. Perhaps, in so doing, I shall be of
service to the novice. The subject, which is very simple and sharply
defined, will show us how one question gives rise to another; how
experimental tests confirm or upset hypotheses, which are, as it were,
a temporary scaffolding; and, lastly, how logic, that severe examiner,
leads us by degrees to generalities which are far more important than
anything that we were led to anticipate at the outset.

And, first of all, does the Pine Processionary possess a special
glandular structure which elaborates the virus, as do, for instance,
the poison-glands of the Wasps and Bees? By no means. Anatomy shows
that the internal structure of the stinging caterpillar is similar to
that of the harmless one. There is nothing more and nothing less.

The poisonous product, of unlocalized origin, results, therefore, from
a general process in which the entire organism is brought into play. It
should, in consequence, be found in the blood, after the manner of urea
in higher animals. This is a suggestion of grave import, but after all
quite valueless without the conclusive verdict of actual experiment.

Five or six Processionaries, pricked with the point of a needle,
furnish me with a few drops of blood. I allow these to soak into a
small square of blotting-paper, which I then apply to my fore-arm with
a waterproof bandage. It is not without a certain anxiety that I await
the outcome of the experiment. The result will show whether the
conclusions already forming in my mind will receive a solid basis or
vanish into thin air.

At a late hour of the night, the pain wakes me, a pain which this time
is an intellectual joy. My anticipations were correct. The blood does
indeed contain the venomous substance. It causes itching, swelling, a
burning sensation, an exudation of serum and, lastly, a shedding of the
skin. I learn more than I had hoped to learn. The test is more valuable
than that of mere contact with the caterpillar could have been. Instead
of treating myself with the small quantity of poison with which the
hairs are smeared, I have gone to the source of the irritant substance
and I thereby gain an increase of discomfort.

Very happy in my suffering, which sets me on a safe path, I continue my
enquiry by arguing thus: the virus in the blood cannot be a living
substance, one that takes part in the working of the organism; it is
rather, like urea, a form of decay, an offthrow of the vital process, a
waste product which is expelled as and when it forms. If this be the
case, I ought to find it in the caterpillar’s droppings, which are made
up of both the digestive and the urinary residues.

Let us describe the new experiment, which is no less positive than the
last. I leave a few pinches of very dry droppings, such as are found in
abundance In the old nests, to soak for two days In sulphuric ether.
The liquid, coloured as it is with the chlorophyll of the caterpillar’s
food, turns a dirty green. Then I repeat precisely the process which I
mentioned when I wanted to prove the innocuousness of the hairs
deprived of their poisonous varnish. I refer to it a second time in
order thoroughly to explain the method pursued and to save repetition
in the various experiments undertaken.

The infusion is filtered, spontaneously evaporated and reduced to a few
drops, with which I soak my stinger. This consists of a small piece of
blotting-paper, folded in four to increase the thickness of the pad and
to give it a greater power of absorption. An area of a square inch or
less suffices; in some cases it is even too much. A novice in this kind
of research-work, I was too lavish with the liniment; and in return for
my generosity I had such a bad time that I make a point of warning any
reader desirous of repeating the experiment upon his own person.

Fully soaked, the square of paper is applied to the fore-arm, on the
inner surface, where the skin is more tender. A sheet of rubber covers
it and, being waterproof, guards against the loss of the poison.
Finally, a linen bandage keeps the whole in place.

On the afternoon of the 4th of June 1897, a memorable date for me, I
test, as I have just said, the etheric extract of the Processionary’s
droppings. All night long, I feel a violent itching, a burning
sensation and shooting pains. On the following day, after twenty hours
of contact, I remove the dressing.

The venomous liquid, too lavishly employed in my fear of failure, has
considerably overflowed the limits of the square of paper. The parts
which it has touched and still more the portion covered by the pad are
swollen and very red; moreover, in the latter case, the skin is ridged,
wrinkled and mortified. It smarts a little and itches; and that is all.

On the following day, the swelling becomes more pronounced and goes
deep into the muscles, which, when touched with the finger, throb like
an inflamed cheek. The colour is a bright carmine and extends all round
the spot which the paper covered. This is due to the escape of some of
the liquid. There is a plentiful discharge of serum, oozing from the
sore in tiny drops. The smarting and itching increase and become so
intense, especially during the night, that, to get a little sleep, I am
driven to employ a palliative, vaseline with borax and a lint dressing.

In five days’ time, it has developed into a hideous ulcer, which looks
more painful than it really is. The red, swollen flesh, quivering and
denuded of its epidermis, provokes commiseration. The person who night
and morning renews my dressing of lint and vaseline is almost sick at
the sight.

“One would think,” she says, “that the dogs had been gnawing your arm.
I do hope you won’t try any more of those horrible decoctions.”

I allow my sympathetic nurse to talk away and am already meditating
further experiments, some of which will be equally painful. O sacred
truth, what can rival thy power over us mortals! Thou turnest my petty
torment into contentment; thou makest me rejoice in my flayed arm! What
shall I gain by it all? I shall know why a wretched caterpillar sets us
scratching ourselves. Nothing more; and that is enough for me.

Three weeks later, new skin is forming, but is covered all over with
painful little pimples. The swelling diminishes; the redness persists
and is still very marked. The effect of the infernal paper lasts a long
time. At the end of a month, I still feel an itching, a burning
irritation, which is intensified by the warmth of the bed-clothes. At
last, a fortnight later, all has disappeared but the redness, of which
I shall retain the marks for a long time yet, though it grows gradually
fainter and fainter. It will take three months or more to vanish
altogether.

We now have some light on the problem: the Processionary’s virus is
certainly an offthrow of the organic factory, a waste product of the
living edifice. The caterpillar discards it with his excrement. But the
material of the droppings has a twofold origin: the greater part
represents the digestive residuum; the rest, in a much smaller
proportion, is composed of the urinary products. To which of the two
does the virus belong? Before going farther, let us permit ourselves a
digression which will assist us in our subsequent enquiries. Let us ask
what advantages the Processionary derives from his urticating product.

I already hear the answer:

“It is a means of protection, of defence. With his poisoned mane, he
repels the enemy.”

I do not clearly perceive the bearing of this explanation. I think of
the creature’s recognized enemies: of the larva of Calosoma sycophanta,
which lives in the nests of the Processionary of the Oak and gobbles up
the inhabitants with never a thought of their burning fleece; of the
Cuckoo, another mighty consumer, so we are told, of the same
caterpillars, who gorges on them to the point of implanting in his
gizzard a bristling coat of their hairs.

I am not aware if the Processionary of the Pine pays a like tribute. I
do know of at least one of his exploiters. This is a Dermestes, [23]
who establishes himself in the silken city and feeds upon the remains
of the defunct caterpillars. This ghoul assures us of the existence of
other consumers, all furnished with stomachs expressly fashioned for
such highly-seasoned fare. For every harvest of living creatures there
is always a harvester.

No, the theory of a special virus, expressly prepared to defend the
Processionary and his emulators in urtication, is not the last word on
the subject. I should find it difficult to believe in such a
prerogative. Why have these caterpillars, more than others, need of
protection? What reasons would make of them a caste apart, endowed with
an exceptional defensive venom? The part which they play in the
entomological world does not differ from that of other caterpillars,
hairy or smooth. It is the naked caterpillars who, in default of a mane
capable of striking awe into the assailant, ought, one would think, to
arm themselves against danger and impregnate themselves with
corrosives, instead of remaining a meek and easy prey. Is it likely
that the shaggy, bristling caterpillar should anoint his fleece with a
formidable cosmetic and his smooth-coated kinsman be unfamiliar with
the chemical properties of the poison beneath his satin skin! These
contradictions do not inspire confidence.

Have we not here, rather, a property common to all caterpillars,
smooth-skinned or hairy? Among the latter, there might be some, just a
few, who, under certain special conditions which will need to be
defined, would be quick to reveal by urtication the venomous nature of
their organic refuse; the others, the vast majority, living outside
these conditions, even though endowed with the necessary product, would
be inexpert at the stinging business and would not produce irritation
by contact. In all, the same virus is to be found, resulting from an
identical vital process. Sometimes it is brought into prominence by the
itching which it produces; sometimes, indeed most often, it remains
latent, unrecognized, if our artifices do not intervene.

What shall these artifices be? Something very simple. I address myself
to the Silkworm. If there be an inoffensive caterpillar in the world,
it is certainly he. Women and children take him up by the handful in
our Silkworm-nurseries; and their delicate fingers are none the worse
for it. The satin-skinned caterpillar is perfectly innocuous to a skin
almost as tender as his own.

But this lack of caustic venom is only apparent. I treat with ether the
excretions of the Silkworm; and the infusion, concentrated into a few
drops, is tested according to the usual method. The result is
wonderfully definite. A smarting sore on the arm, similar in its mode
of appearance and in its effects to that produced by the droppings of
the Processionary, assures me that logic was right.

Yes, the virus which makes one scratch so much, which blisters and eats
away the skin, is not a defensive product vested in only a few
caterpillars. I recognize it, with its invariable properties, even in a
caterpillar which at first sight appears as though it could not possess
anything of the kind.

The Silkworm’s virus, besides, is not unknown in my village. The casual
observation of the peasant-woman has outstripped the precise
observation of the man of science. The women and girls entrusted with
the rearing of the Silkworm—the magnanarelles as they are
called—complain of certain tribulations caused, they say, by lou verin
di magnan, the Silkworms’ poison. This trouble consists of a violent
itching of the eyelids, which become red and swollen. In the case of
the more susceptible, there is a rash and the skin peels off the
fore-arm, which the turned-up sleeves fail to protect during work.

I now know the cause of this little trouble, my plucky magnanarelles.
It is not contact with the worm that afflicts you; you need have no
fear of handling him. It is only the litter that you need distrust.
There, jumbled up with the remains of the mulberry-leaves, is a copious
mass of droppings, impregnated with the substance which has just so
painfully eaten into my skin; there and there only is lou verin, as you
call it.

It is a relief merely to know the cause of one’s trouble; but I will
provide you with another consolation. When you remove the litter and
renew the leaves, you should raise the irritant dust as little as
possible; you should avoid lifting your hands to your face, above all
to your eyes; and it is just as well to turn down your sleeves in order
to protect your arms. If you take these precautions, you will suffer no
unpleasantness.

The successful result obtained with the Silkworm caused me to foresee a
similar success with any caterpillar that I might come across. The
facts fully confirmed my expectations. I tested the stercoral pellets
of various caterpillars, not selected, but just as the hazard of
collecting provided them: the Great Tortoiseshell, the Heath
Fritillary, the Large Cabbage Butterfly, the Spurge Hawk-moth, the
Great Peacock Moth, the Death’s-head Moth, the Puss-moth, the
Tiger-moth and the Arbutus Liparis. All my tests, with not a single
exception, brought about stinging, of various degrees of violence, it
is true. I attribute these differences in the result to the greater or
lesser quantities of the virus employed, for it is impossible to
measure the dose.

So the urticating excretion is common to all the caterpillars. By a
very unexpected reversion of the usual order of things, the popular
repugnance is well-founded; prejudice becomes truth: all caterpillars
are venomous. We must draw a distinction, however: with the same
venomous properties, some are inoffensive and others, far less
numerous, are to be feared. Whence comes this difference?

I note that the caterpillars marked out as stinging live in communities
and weave themselves dwellings of silk, in which they stay for long
periods. Moreover, they are furry. Of this number are the Pine
Processionary, the Oak Processionary and the caterpillars of various
Lipares.

Let us consider the first-named in particular. His nest, a voluminous
bag spun at the tip of a branch, is magnificent in its silky whiteness,
on the outside; inside, it is a disgusting cesspit. The colony remains
in it all day and for the greater part of the night. It sallies forth
in procession only in the late hours of twilight, to browse upon the
adjacent foliage. This long internment leads to a considerable
accumulation of droppings in the heart of the dwelling.

From all the threads of this labyrinth hang chaplets of these
droppings; the walls are upholstered with them in all the corridors;
the little narrow chambers are encumbered with them. From a nest the
size of a man’s head I have obtained, with a sieve, over three-quarters
of a pint of stercoral pellets.

Now it is in the midst of this ordure that the caterpillars live and
have their being; in the midst of it they move, swarm and sleep. The
results of this utter contempt for the rules of cleanliness are
obvious. Certainly, the Processionary does not soil his coat by contact
with those dry pellets; he leaves his home with his costume neat and
glossy, suggesting not a suspicion of uncleanliness. No matter: by
constantly rubbing against the droppings, his bristles are inevitably
smeared with virus and their barbs poisoned. The caterpillar becomes
irritant, because his manner of life subjects him to prolonged contact
with his own ordure.

Now consider the Hedgehog Caterpillar. Why is he harmless, despite his
fierce and hirsute aspect? Because he lives in isolation and is always
on the move. His mane, apt though it be to collect and retain irritant
particles, will never give us the itch, for the simple reason that the
caterpillar does not lie on his excretions. Distributed all over the
fields and far from numerous, owing to the caterpillar’s solitary
habits, the droppings, though poisonous, cannot transfer their
properties to a fleece which does not come into contact with them. If
the Hedgehog lived in a community, in a nest serving as a cesspit, he
would be the foremost of our stinging caterpillars.

At first sight, the barrack-rooms of the Silkworm-nurseries seem to
fulfil the conditions necessary to the surface venom of the worms. Each
change of litter results in the removal of basketfuls of droppings from
the trays. Over this heaped-up ordure the Silkworms swarm. How is it
that they do not acquire the poisonous properties of their own
excrement?

I see two reasons. In the first place, they are hairless; and a
brushlike coat may well be indispensable to the collection of the
virus. In the second place, far from lying in the filth, they live
above the soiled stratum, being largely separated from it by the bed of
leaves, which is renewed several times a day. Despite crowding, the
population of a tray has nothing that can be compared with the ordinary
habits of the Processionary; and so it remains harmless, in spite of
its stercoral toxin.

These first enquiries lead us to conclusions which themselves are very
remarkable. All caterpillars excrete an urticating matter, which is
identical throughout the series. But, if the poison is to manifest
itself and to cause us that characteristic itching, it is indispensable
that the caterpillar shall dwell in a community, spending long periods
in the nest, a silken bag laden with droppings. These furnish the
virus; the caterpillar’s hairs collect it and transfer it to us.

The time has come to tackle the problem from another point of view. Is
this formidable matter which always accompanies the excretions a
digestive residuum? Is it not rather one of those waste substances
which the organism engenders while at work, waste substances designated
by the general appellation of urinary products?

To isolate these products, to collect them separately, would scarcely
be practicable, if we did not have recourse to what follows on the
metamorphosis. Every Moth, on emerging from her chrysalis, rejects a
copious mixture of uric acid and various humours of which very little
is as yet known. It may be compared with the broken plaster of a
building rebuilt on a new plan and represents the by-products of the
mighty labours accomplished in the transfigured insect. These remains
are essentially urinary products, with no admixture of digested
foodstuffs.

To what insect shall I apply for this residuum? Chance does many
things. I collect, from the old elm-tree in the garden, about a hundred
curious caterpillars. They have seven rows of prickles of an amber
yellow, a sort of bush with four or five branches. I shall learn from
the Butterfly that they belong to the Great Tortoiseshell (Vanessa
polychloros, Lin.).

Reared on elm-leaves under a wire-gauze cover, my caterpillars undergo
their transformation towards the end of May. Their chrysalids are
specked with brown on a whitish ground and display on the under surface
six radiant silvery spots, a sort of decorative tinsel, like so many
mirrors. Fixed by the tail with a silken pad, they hang from the top of
the dome, swinging at the least movement and emitting vivid flashes of
light from their reflectors. My children are amazed at this living
chandelier. It is a treat for them when I allow them to come and admire
it in my animal studio.

Another surprise awaits them, this time a tragic one, however. A
fortnight later, the Butterflies emerge. I have placed under the cover
a large sheet of white paper, which will receive the desired products.
I call the children. What do they see on the paper?

Large spots of blood. Under their very eyes, from up there, at the top
of the dome, a butterfly lets fall a great red drop: plop! No joy for
the children to-day; anxiety rather, almost fear.

I send them away, saying to them:

“Be sure and remember, kiddies, what you have just seen; and, if ever
any one talks to you about showers of blood, don’t be silly and
frightened. A pretty Butterfly is the cause of those blood-red stains,
which have been known to terrify country-folk. The moment she is born,
she casts out, in the form of a red liquid, the remains of her old
caterpillar body, a body remodelled and reborn in a beautiful shape.
That is the whole secret.”

When my artless visitors have departed, I resume my examination of the
rain of blood falling under the cover. Still clinging to the shell of
its chrysalis, each Tortoiseshell ejects and sheds upon the paper a
great red drop, which, if left standing, deposits a powdery pink
sediment, composed of urates. The liquid is now a deep crimson.

When the whole thing is perfectly dry, I cut out of the spotted paper
some of the richer stains and steep the bits in ether. The spots on the
paper remain as red as at the outset; and the liquid assumes a light
lemon tint. When reduced by evaporation to a few drops, this liquid
provides me with what I require to soak my square of blotting-paper.

What shall I say to avoid repeating myself? The effects of the new
caustic are precisely the same as those which I experienced when I used
the droppings of the Processionary. The same itching, the same burning,
the same swelling with the flesh throbbing and inflamed, the same
serous exudation, the same peeling of the skin, the same persistent
redness, which lingers for three or four months, long after the
ulceration itself has disappeared.

Without being very painful, the sore is so irksome and above all looks
so ugly that I swear never to let myself in for it again. Henceforth,
without waiting for the thing to eat into my flesh, I shall remove the
caterpillar plaster as soon as I feel a conclusive itching.

In the course of these painful experiences, friends upbraid me with not
having recourse to the assistance of some animal, such as the
Guinea-pig, that stock victim of the physiologists. I take no note of
their reproaches. The animal is a stoic. It says nothing of its
sufferings. If, the torture being a little too intense, it complains, I
am in no position to interpret its cries exactly or to attribute them
to a definite impression.

The Guinea-pig will not say:

“It smarts, it itches, it burns.”

He will simply say:

“That hurts.”

As I want to know the details of the sensations experienced, the best
thing is to resort to my own skin, the only witness on whose evidence I
can rely implicitly.

At the risk of provoking a smile, I will venture on another confession.
As I begin to see into the matter more clearly, I hesitate to torture
or destroy a single creature in God’s great community. The life of the
least of these is a thing to be respected. We can take it away, but we
cannot give it. Peace to those innocents, so little interested in our
investigations! What does our restless curiosity matter to their calm
and sacred ignorance? If we wish to know, let us pay the price
ourselves as far as possible. The acquisition of an idea is well worth
the sacrifice of a bit of skin.

The Elm Tortoiseshell, with her rain of blood, may leave us to a
certain extent in doubt. Might not this strange red substance, with its
unusual appearance, contain a poison which is likewise exceptional? I
address myself therefore to the Mulberry Bombyx, to the Pine Bombyx and
to the Great Peacock. I collect the uric excretions ejected by the
newly hatched Moths.

This time, the liquid is whitish, sullied here and there with uncertain
tints. There is no blood-red colouration; but the result is the same.
The virulent energy manifests itself in the most definite manner.
Therefore the Processionary’s virus exists equally in all caterpillars,
in all Butterflies and Moths emerging from the chrysalis; and this
virus is a by-product of the organism, a urinary product.

The curiosity of our minds is insatiable. The moment a reply is
obtained, a fresh question arises. Why should the Lepidoptera alone be
endowed in this manner? The organic labours accomplished within them
cannot differ greatly, as to the nature of the materials, from those
presiding over the maintenance of life in other insects. Therefore
these others also elaborate a by-product which has stinging powers.
This can be verified—and that forthwith—with the elements at my
disposal.

The first reply is furnished by Cetonia floricola, of which Beetle I
collect half a dozen chrysalids from a heap of leaves half-converted
into mould. A box receives my find, laid on a sheet of white paper, on
which the urinary fluid of the perfect insect will fall as soon as the
caskets are broken.

The weather is favourable and I have not long to wait. The thing is
done: the matter rejected is white, the usual colour of these residua,
in the great majority of insects, at the moment of the metamorphosis.
Though by no means abundant, it nevertheless provokes on my fore-arm a
violent itching, together with mortification of the skin, which comes
off in flakes. The reason why it does not display a more distinct sore
is that I judged it prudent to end the experiment. The burning and
itching tell me enough as to the results of a contact unduly prolonged.

Now to the Hymenoptera. I have not in my possession, I regret to say,
any of those with whom my rearing-chambers used formerly to provide me,
whether Honey-bee or Hunting Wasps. I have only a Green Saw-fly, whose
larva lives in numerous families on the leaves of the alder. Reared
under cover, this larva provides me with enough tiny black droppings to
fill a thimble. That is sufficient: the urtication is quite definite.

I take next the insects with incomplete transformations. My recent
rearings have given me quite a collection of excretions emanating from
the Orthoptera. I consult those of the Vine Ephippiger [24] and the
Great Grey Locust. Both sting to a degree which once more makes me
regret my lavish hand.

We will be satisfied with this; indeed my arms demand as much, for,
tattooed with red squares, they refuse to make room for fresh
brandings. The examples are sufficiently varied to impose the following
conclusion: the Processionary’s virus is found in a host of other
insects, apparently even in the entire series. It is a urinary product
inherent in the entomological organism.

The dejections of insects, especially those evacuated at the end of the
metamorphosis, contain or are even almost entirely composed of urates.
Can the stinging material be the inevitable associate of uric acid? It
should then form part of the excrement of the bird and the reptile,
which in both cases is very rich in urates. Here again is a suspicion
worthy of verification by experiment.

For the moment it is impossible for me to question the reptile; it is
easy, on the other hand, to interrogate the bird, whose reply will
suffice. I accept what is offered by chance: an insectivorous bird, the
Swallow, and a graminivorous bird, the Goldfinch. Well, their urinary
dejections, when carefully separated from the digestive residua, have
not the slightest stinging effect. The virus that causes itching is
independent therefore of uric acid. It accompanies it in the insect
class, without being its invariable concomitant every elsewhere.

A last step remains for us to take, namely, to isolate the stinging
element and to obtain it in quantities permitting of precise enquiries
into its nature and properties. It seems to me that medical science
might turn to account a material whose energy rivals that of
cantharides, if it does not exceed it. The question appeals to me. I
would gladly return to my beloved chemistry; but I should want
reagents, apparatus, a laboratory, a whole costly arsenal of which I
must not dream, afflicted as I am with a terrible ailment:
impecuniosity, the searcher’s habitual lot.



CHAPTER IX

THE PSYCHES: THE LAYING


In the springtime, old walls and dusty roads harbour a surprise for
whoso has eyes to see. Tiny faggots, for no apparent reason, set
themselves in motion and make their way along by sudden jerks. The
inanimate comes to life, the immovable stirs. How does this come about?
Look closer and the motive power will stand revealed.

Enclosed within the moving bundle is a fairly well-developed
caterpillar, prettily striped in black and white. Seeking for food or
perhaps for a spot where the transformation can be effected, he hurries
along timidly, attired in a queer rig-out of twigs from which nothing
emerges except the head and the front part of the body, which is
furnished with six short legs. At the least alarm he goes right in and
does not budge again. This is the whole secret of the little roaming
bundle of sticks.

The faggot caterpillar belongs to the Psyche group, whose name conveys
an allusion to the classic Psyche, symbolical of the soul. We must not
allow this phrase to carry our thoughts to loftier heights than is
fitting. The nomenclator, with his rather circumscribed view of the
world, did not trouble about the soul when inventing his descriptive
label. He simply wanted a pretty name; and certainly he could have hit
on nothing better.

To protect himself from the weather, our chilly, bare-skinned Psyche
builds himself a portable shelter, a travelling cottage which the owner
never leaves until he becomes a Moth. It is something better than a hut
on wheels with a thatched roof to it: it is a hermit’s frock, made of
an unusual sort of frieze. In the valley of the Danube the peasant
wears a goatskin cloak fastened with a belt of rushes. The Psyche dons
an even more rustic apparel. He makes himself a suit of clothes out of
hop-poles. It is true that, beneath this rude conglomeration, which
would be a regular hair-shirt to a skin as delicate as his, he puts a
thick lining of silk. The Clythra Beetle garbs himself in pottery; this
one dresses himself in a faggot.

In April, on the walls of my chief observatory, that famous pebbly acre
with its wealth of insect life, I find the Psyche who is to furnish me
with my most circumstantial and detailed records. [25] He is at this
period in the torpor of the approaching metamorphosis. As we can ask
him nothing else for the moment, let us look into the construction and
composition of his faggot.

It is a not irregular structure, spindle-shaped and about an inch and a
half long. The pieces that compose it are fixed in front and free at
the back, are arranged anyhow and would form a rather ineffective
shelter against the sun and rain if the recluse had no other protection
than his thatched roof.

The word thatch is suggested to my mind by a summary inspection of what
I see, but it is not an exact expression in this case. On the contrary,
graminaceous straws are rare, to the great advantage of the future
family, which, as we shall learn presently, would find nothing to suit
them in jointed planks. What predominates is remnants of very small
stalks, light, soft and rich in pith, such as are possessed by various
Chicoriaceæ. I recognize in particular the floral stems of the
mouse-ear hawkweed and the Nimes pterotheca. Next come bits of
grass-leaves, scaly twigs provided by the cypress-tree and all sorts of
little sticks, coarse materials adopted for the lack of anything
better. Lastly, if the favourite cylindrical pieces fall short, the
mantle is sometimes finished off with an ample flounced tippet, that is
to say, with fragments of dry leaves of any kind.

Incomplete as it is, this list shows us that the caterpillar apart from
his preference for pithy morsels, has no very exclusive tastes. He
employs indifferently anything that he comes upon, provided that it be
light, very dry, softened by long exposure to the air and of suitable
dimensions. All his finds, if they come anywhere near his estimates,
are used just as they are, without any alterations or sawing to reduce
them to the proper length. The Psyche does not trim the laths that go
to form his roof; he gathers them as he finds them. His work is limited
to imbricating them one after the other by fixing them at the fore-end.

In order to lend itself to the movements of the journeying caterpillar
and in particular to facilitate the action of the head and legs when a
new piece is to be placed in position, the front part of the sheath
requires a special structure. Here a casing of beams is no longer
allowable, for their length and stiffness would hamper the artisan and
even make his work impossible; what is essential here is a flexible
neck, able to bend in all directions. The assemblage of stakes does, in
fact, end suddenly at some distance from the fore-part and is there
replaced by a collar in which the silken woof is merely hardened with
very tiny ligneous particles, tending to strengthen the material
without impairing its flexibility. This collar, which gives free
movement, is so important that all the Psyches make equal use of it,
however much the rest of the work may differ. All carry, in front of
the faggot of sticks, a yielding neck, soft to the touch, formed inside
of a web of pure silk and velveted outside with a fine sawdust which
the caterpillar obtains by crushing with his mandibles any sort of dry
straw.

A similar velvet, but lustreless and faded, apparently through age,
finishes the sheath at the back, in the form of a rather long, bare
appendix, open at the end.

Let us now remove the outside of the straw envelope, shredding it
piecemeal. The demolition gives us a varying number of joists: I have
counted as many as eighty and more. The ruin that remains is a
cylindrical sheath wherein we discover, from one end to the other, the
structure which we perceived at the front and rear, the two parts which
are naturally bare. The tissue everywhere is of very stout silk, which
resists without breaking when pulled by the fingers, a smooth tissue,
beautifully white inside, drab and wrinkled outside, where it bristles
with encrusted woody particles.

There will be an opportunity later to discover by what means the
caterpillar makes himself so complicated a garment, in which are laid
one upon the other, in a definite order, first, the extremely fine
satin which is in direct contact with the skin; next, the mixed stuff,
a sort of frieze dusted with ligneous matter, which saves the silk and
gives consistency to the work; lastly, the surtout of overlapping
laths.

While retaining this general threefold arrangement, the scabbard offers
notable variations of structural detail in the different species. Here,
for instance, is a second Psyche, [26] the most belated of the three
which I have chanced to come upon. I meet him towards the end of June,
hurrying across some dusty path near the houses. His cases surpass
those of the previous species both in size and in regularity of
arrangement. They form a thick coverlet, of many pieces, in which I
recognize here fragments of hollow stalks, there bits of fine straw,
with perhaps straps formed of blades of grass. In front there is never
any mantilla of dead leaves, a troublesome piece of finery which,
without being in regular use, is pretty frequent in the costume of the
first-named species. At the back, no long, denuded vestibule. Save for
the indispensable collar at the aperture, all the rest is cased in
logs. There is not much variety about the thing, but, when all is said,
there is a certain elegance in its stern faultlessness.

The smallest in size and simplest in dress is the third, [27] who is
very common at the end of winter on the walls, as well as in the
furrows of the barks of gnarled old trees, be they olive-trees,
holm-oaks, elms or almost any other. His case, a modest little bundle,
is hardly more than two-fifths of an inch in length. A dozen rotten
straws, gleaned at random and fixed close to one another in a parallel
direction, represent, with the silk sheath, his whole outlay on dress.
It would be difficult to clothe one’s self more economically.

This pigmy, apparently so uninteresting, shall supply us with our first
records of the curious life-story of the Psyches. I gather him in
profusion in April and instal him in a wire bell-jar. What he eats I
know not. My ignorance would be grievous under other conditions; but at
present I need not trouble about provisions. Taken from their walls and
trees, where they had suspended themselves for their transformation,
most of my little Psyches are in the chrysalis state. A few of them are
still active. They hasten to clamber to the top of the trellis-work;
they fix themselves there perpendicularly by means of a little silk
cushion; then everything is still.

June comes to an end; and the male Moths are hatched, leaving the
chrysalid wrapper half caught in the case, which remains fixed where it
is and will remain there indefinitely until dismantled by the weather.
The emergence is effected through the hinder end of the bundle of
sticks, the only way by which it can be effected. Having permanently
closed the top opening, the real door of the house, by fastening it to
the support which he has chosen, the caterpillar therefore has turned
the other way round and undergone his transformation in a reversed
position, which enables the adult insect to emerge through the outlet
made at the back, the only one now free.

For that matter, this is the method followed by all the Psyches. The
case has two apertures. The front one, which is more regular and more
carefully constructed, is at the caterpillar’s service so long as
larval activity lasts. It is closed and firmly fastened to its support
at the time of the nymphosis. The hinder one, which is faulty and even
hidden by the sagging of the sides, is at the Moth’s service. It does
not really open until right at the end, when pushed by the chrysalis or
the adult insect.

In their modest pearl-grey dress, with their insignificant
wing-equipment, hardly exceeding that of a Common Fly, our little Moths
are still not without elegance. They have handsome feathery plumes for
antennæ; their wings are edged with delicate fringes. They whirl very
fussily inside the bell-jar; they skim the ground, fluttering their
wings; they crowd eagerly around certain sheaths which nothing on the
outside distinguishes from the others. They alight upon them and sound
them with their plumes.

This feverish agitation marks them as lovers in search of their brides.
This one here, that one there, each of them finds his mate. But the coy
one does not leave her home. Things happen very discreetly through the
wicket left open at the free end of the case. The male stands on the
threshold of this back-door for a little while; and then it is over:
the wedding is finished. There is no need for us to linger over these
nuptials in which the parties concerned do not know, do not see each
other.

I hasten to place in a glass tube the few cases in which the mysterious
events have happened. Some days later, the recluse comes out of the
sheath and shows herself in all her wretchedness. Call that little
fright a Moth! One cannot easily get used to the idea of such poverty.
The caterpillar of the start was no humbler-looking. There are no
wings, none at all; no silky fur either. At the tip of the abdomen, a
round, tufty pad, a crown of dirty-white velvet; on each segment, in
the middle of the back, a large rectangular dark patch: these are the
sole attempts at ornament. The mother Psyche renounces all the beauty
which her name of Moth promised.

From the centre of the hairy coronet a long ovipositor stands out,
consisting of two parts, one stiff, forming the base of the implement,
the other soft and flexible, sheathed in the first just as a telescope
fits in its tube. The laying mother bends herself into a hook, grips
the lower end of her case with her six feet and drives her probe into
the back-window, a window which serves manifold purposes, allowing of
the consummation of the clandestine marriage, the emergence of the
fertilized bride, the installation of the eggs and, lastly, the exodus
of the young family.

There, at the free end of her case, the mother remains for a long time,
bowed and motionless. What can she be doing in this contemplative
attitude? She is lodging her eggs in the house which she has just left;
she is bequeathing the maternal cottage to her heirs. Some thirty hours
pass and the ovipositor is at last withdrawn. The laying is finished.

A little wadding, supplied by the coronet on the hind-quarters, closes
the door and allays the dangers of invasion. The fond mother makes a
barricade for her brood of the sole ornament which, in her extreme
indigence, she possesses. Better still, she makes a rampart of her
body. Bracing herself convulsively on the threshold of her home, she
dies there, dries up there, devoted to her family even after death. It
needs an accident, a breath of air, to make her fall from her post.

Let us now open the case. It contains the chrysalid wrapper, intact
except for the front breach through which the Psyche emerged. The male,
because of his wings and his plumes, very cumbersome articles when he
is about to make his way through the narrow pass, takes advantage of
his chrysalis state to make a start for the door and come out half-way.
Then, bursting his amber tunic, the delicate Moth finds an open space,
where flight is possible, right in front of him. The mother, unprovided
with wings and plumes, is not compelled to observe any such
precautions. Her cylindrical form, bare and differing but little from
that of the caterpillar, allows her to crawl, to slip into the narrow
passage and to come forth without obstacle. Her cast chrysalid skin is,
therefore, left right at the back of the case, well covered by the
thatched roof.

And this is an act of prudence marked by exquisite tenderness. The
eggs, in fact, are packed in the barrel, in the parchmentlike wallet
formed by the slough. The mother has thrust her telescopic ovipositor
to the bottom of that receptacle and has methodically gone on laying
until it is full. Not satisfied with bequeathing her home and her
velvet coronet to her offspring, as a last sacrifice she leaves them
her skin.

With a view to observing at my ease the events which are soon to
happen, I extract one of these chrysalid bags, stuffed with eggs, from
its faggot and place it by itself, beside its case, in a glass tube. I
have not long to wait. In the first week of July, I find myself all of
a sudden in possession of a large family. The quickness of the hatching
balked my watchfulness. The new-born caterpillars, about forty in
number, have already had time to garb themselves.

They wear a Persian head-dress, a mage’s tiara in dazzling white plush.
Or, to abandon high-flown language, let us say a cotton night-cap
without a tassel; only the cap does not stand up from the head: it
covers the hind-quarters. Great animation reigns in the tube, which is
a spacious residence for such vermin. They roam about gaily, with their
caps sticking up almost perpendicular to the floor. With a tiara like
that and things to eat, life must be sweet indeed.

But what do they eat? I try a little of everything that grows on the
bare stone and the gnarled old trees. Nothing is welcomed. More eager
to dress than to feed themselves, the Psyches scorn what I set before
them. My ignorance as an insect-breeder will not matter, provided that
I succeed in seeing with what materials and in what manner the first
outlines of the cap are woven.

I may fairly hope to achieve this ambition, as the chrysalid bag is far
from having exhausted its contents. I find in it, teeming amid the
rumpled wrapper of the eggs, an additional family as numerous as the
swarm that is already out. The total laying must therefore amount to
five or six dozen. I transfer to another receptacle the precocious band
which is already dressed and keep only the naked laggards in the tube.
They have bright red heads, with the rest of their bodies dirty white;
and they measure hardly a twenty-fifth of an inch in length.

My patience is not long put to the test. Next day, little by little,
singly or in groups, the belated grubs quit the chrysalid bag. They
come out without breaking the frail wallet, through the front breach
made by the liberation of the mother. Not one of them utilizes it as a
dress-material, though it has the delicacy and amber colouring of an
onion-skin; nor do any of them make use of a fine quilting which lines
the inside of the bag and forms an exquisitely soft bed for the eggs.
This down, whose origin we shall have to investigate presently, ought,
one would say, to make an excellent blanket for these chilly ones,
impatient to cover themselves up. Not a single one uses it; there would
not be enough to go round.

All go straight to the coarse faggot, which I left in contact with the
wallet that was the chrysalis. Time presses. Before making your
entrance into the world and going agrazing, you must first be clad. All
therefore, with equal fury, attack the old sheath and hastily dress
themselves in the mother’s cast clothes. Some turn their attention to
bits that happen to be open lengthwise and scrape the soft, white inner
layer; others, greatly daring, penetrate into the tunnel of a hollow
stalk and go and collect their cotton goods in the dark. At such times
the materials are first-class; and the garment woven is of a dazzling
white. Others bite deep into the piece which they select and make
themselves a motley garment, in which dark-coloured particles mar the
snowy whiteness of the rest.

The tool which they use for their gleaning consists of the mandibles,
shaped like wide shears with five strong teeth apiece. The two planes
fit into each other and form an implement capable of seizing and
slicing any fibre, however small. Seen under the microscope, it is a
wonderful specimen of mechanical precision and power. Were the Sheep
similarly equipped in proportion to her size, she would browse upon the
bottom of the trees instead of cropping the grass.

A very instructive workshop is that of the Psyche-vermin toiling to
make themselves a cotton night-cap. There are numbers of things to
remark in both the finish of the work and the ingenuity of the methods
employed. To avoid repeating ourselves, we will say nothing about these
yet, but wait for a little and return to the subject when setting forth
the talents of a second Psyche, of larger stature and easier to
observe. The two weavers observe exactly the same procedure.

Nevertheless let us take a glance at the bottom of the egg-cup, a
general workyard in which I instal my dwarfs as the cases turn them
out. There are some hundreds of them, with the sheaths from which they
came and an assortment of clipped stalks, chosen from among the driest
and richest in pith. What a whirl! What bewildering animation!

In order to see man, Micromégas cut himself a lens out of a diamond of
his necklace; he held his breath lest the storm from his nostrils
should blow the mite away. I in my turn will be the good giant, newly
arriving from Sirius; I screw a magnifying-glass into my eye and am
careful not to breathe for fear of overturning and sweeping out of
existence my cotton-workers. If I need one of them, to focus him under
a stronger glass, I lime him as it were, seizing him with the fine
point of a needle which I have passed over my lips. Taken away from his
work, the tiny caterpillar struggles at the end of the needle, shrivels
up, makes himself, small as he is, still smaller; he strives to
withdraw as far as possible into his clothing, which as yet is
incomplete, the merest flannel vest or even a narrow scarf, covering
nothing but the top of his shoulders. Let us leave him to complete his
coat. I give a puff; and the creature is swallowed up in the crater of
the egg-cup.

And this speck is alive. It is industrious; it is versed in the art of
blanket-making. An orphan, born that moment, it knows how to cut itself
out of its dead mother’s old clothes the wherewithal to clothe itself
in its turn. Soon it will become a carpenter, an assembler of timber,
to make a defensive covering for its delicate fabric. What must
instinct be, to be capable of awakening such industries in an atom!

It is at the end of June also that I obtain, in his adult shape, the
Psyche whose scabbard is continued underneath by a long, naked
vestibule. Most of the cases are fastened by a silk pad to the
trelliswork of the cage and hang vertically, like stalactites. Some few
of them have never left the ground. Half immersed in the sand, they
stand erect, with their rear in the air and their fore-part buried and
firmly anchored to the side of the pan by means of a silky paste.

This inverted position excludes any idea of weight as a guide in the
caterpillar’s preparations. An adept at turning round in his cabin, he
is careful, before he sinks into the immobility of pupadom, to turn his
head now upwards, now downwards, towards the opening, so that the adult
insect, which is much less free than the larva in its movements, may
reach the outside without obstacle.

Moreover, it is the pupa itself, the unbending chrysalis, incapable of
turning and obliged to move all in one piece, which, stubbornly
crawling, carries the male to the threshold of the case. It emerges
half way at the end of the uncovered silky vestibule and there breaks,
obstructing the opening with its slough as it does so. For a time the
Moth stands still on the roof of the cottage, allowing his humours to
evaporate, his wings to spread and gather strength; then at last the
gallant takes flight, in search of her for whose sake he has made
himself so spruce.

He wears a costume of deepest black, all except the edges of the wings,
which, having no scales, remain diaphanous. His antennæ, likewise
black, are wide and graceful plumes. Were they on a larger scale, they
would throw the feathered beauty of the Marabou and Ostrich into the
shade. The bravely beplumed one visits case after case in his tortuous
flight, prying into the secrets of those alcoves. If things go as he
wishes, he settles, with a quick flutter of his wings, on the extremity
of the denuded vestibule. Comes the wedding, as discreet as that of the
smaller Psyche. Here is yet another who does not see or at most catches
a fleeting glimpse of her for whose sake he has donned Marabou-feathers
and a black-velvet cloak.

The recluse on her side is equally impatient. The lovers are
short-lived; they die in my cages within three or four days, so that,
for long intervals, until the hatching of some late-comer, the female
population is short of suitors. So, when the morning sun, already hot,
strikes the cage, a very singular spectacle is repeated many times
before my eyes. The entrance to the vestibule swells imperceptibly,
opens and emits a mass of infinitely delicate down. A Spider’s web,
carded and made into wadding, would give nothing of such gossamer
fineness. It is a vaporous cloud. Then, from out of this incomparable
eiderdown, appear the head and fore-part of a very different sort of
caterpillar from the original collector of straws.

It is the mistress of the house, the marriageable Moth, who, feeling
her hour about to come and failing to receive the expected visit,
herself makes the advances and goes, as far as she can, to meet her
plumed swain. He does not come hastening up and for good reason: there
is not a male left in the establishment. For two or three hours the
poor forsaken one leans, without moving, from her window. Then, tired
of waiting, very gently she goes indoors again, backwards, and returns
to her cell.

Next day, the day after and later still, as long as her strength
permits, she reappears on her balcony, always in the morning, in the
soft rays of a warm sun and always on a sofa of that incomparable down,
which disperses and turns to vapour if I merely fan it with my hand.
Again no one comes. For the last time the disappointed Moth goes back
to her boudoir, never to leave it again. She dies in it, dries up, a
useless thing. I hold my bell-jars responsible for this crime against
motherhood. In the open fields, without a doubt, sooner or later wooers
would have appeared, coming from the four winds.

The said bell-jars have an even more pitiful catastrophe on their
conscience. Sometimes, leaning too far from her window, miscalculating
the balance between the front of the body, which is at liberty, and the
back, which remains sheathed in its case, the Moth allows herself to
drop to the ground. It is all up now with the fallen one and her
lineage. Still, there is one good thing about it. Accidents such as
this lay bare the mother Psyche, without our having to break into her
house.

What a miserable creature she is, a great deal uglier than the original
caterpillar! Here transfiguration spells disfigurement, progress means
retrogression. What we have before our eyes is a wrinkled satchel, an
earthy-yellow sausage; and this horror, worse than a maggot, is a Moth
in the full bloom of life, a genuine adult Moth. She is the betrothed
of the elegant black Bombyx, all plumed with Marabou-feathers, and
represents to him the last word in beauty. As the proverb says, beauty
lies in lovers’ eyes: a profound truth which the Psyche confirms in
striking fashion.

Let us describe the ugly little sausage. A very small head, a paltry
globule, disappearing almost entirely in the folds of the first
segment. What need is there of cranium and brains for a germ-bag! And
so the tiny creature almost does without them, reduces them to the
simplest expression. Nevertheless, there are two black ocular specks.
Do these vestigial eyes see their way about? Not very clearly, we may
be sure. The pleasures of light must be very small for this
stay-at-home, who appears at her window only on rare occasions, when
the male Moth is late in arriving.

The legs are well-shaped, but so short and weak that they are of no use
at all for locomotion. The whole body is a pale yellow, semitransparent
in front, opaque and stuffed with eggs behind. Underneath the first
segments is a sort of neck-band, that is to say, a dark stain, the
vestige of a crop showing through the skin. A pad of short down ends
the oviferous part at the back. It is all that remains of a fleece, of
a thin velvet which the insect rubs off as it moves backwards and
forwards in its narrow lodging. This forms the flaky mass which whitens
the trysting-window at the wedding-time and also lines the inside of
the sheath with down. In short, the creature is little more than a bag
swollen with eggs for the best part of its length. I know nothing lower
in the scale of wretchedness.

The germ-bag moves, but not, of course, with those vestiges of legs
which form too short and feeble supports; it gets about in a way that
allows it to progress on its back, belly or side indifferently. A
groove is hollowed out at the hinder end of the bag, a deep, dividing
groove which cuts the insect into two. It runs to the front part,
spreading like a wave, and gently and slowly reaches the head. This
undulation constitutes a step. When it is done, the animal has advanced
about a twenty-fifth part of an inch.

To go from one end to the other of a box two inches long and filled
with fine sand, the living sausage takes nearly an hour. It is by
crawling like this that it moves about in its case, when it comes to
the threshold to meet its visitor and goes in again.

For three or four days, exposed to the roughness of the soil, the
oviferous bag leads a wretched life, creeping about at random, or, more
often, standing still. No Moth pays attention to the poor thing, who
possesses no attractions outside her home; the lovers pass by with an
indifferent air. This coolness is logical enough. Why should she become
a mother, if her family is to be abandoned to the inclemencies of the
public way? And so, after falling by accident from her case, which
would have been the cradle of the youngsters, the wanderer withers in a
few days and dies childless.

The fertilized ones—and these are the more numerous—the prudent ones
who have saved themselves from a fall by being less lavish with their
appearances at the window, reenter the sheath and do not show
themselves again once the Moth’s visit to the threshold is over. Let us
wait a fortnight and then open the case lengthwise with our scissors.
At the end, in the widest part, opposite the vestibule, is the slough
of the chrysalis, a long, fragile, amber-coloured sack, open at the end
that contains the head, the end facing the exit-passage. In this sack,
which she fills like a mould, lies the mother, the egg-bladder, now
giving no sign of life.

From this amber sheath, which presents all the usual characteristics of
a chrysalis, the adult Psyche emerged, in the guise of a shapeless
Moth, looking like a big maggot; at the present time, she has slipped
back into her old jacket, moulding herself into it in such a way that
it becomes difficult to separate the container from the contents. One
would take the whole thing for a single body.

It seems very likely that this cast skin, which occupies the best place
in the home, formed the Psyche’s refuge when, weary of waiting on the
threshold of her hall, she retired to the back room. She has therefore
gone in and out repeatedly. This constant going and coming, this
continual rubbing against the sides of a narrow corridor, just wide
enough for her to pass through, ended by stripping her of her down. She
had a fleece to start with, a very light and scanty fleece, it is true,
but still a vestige of the costume which Moths are wont to wear. This
fluff she has lost. What has she done with it?

The Eider robs herself of her down to make a luxurious bed for her
brood; the new-born Rabbits lie on a mattress which their mother cards
for them with the softest part of her fur, shorn from the belly and
neck, wherever the shears of her front teeth can reach it. This fond
tenderness is shared by the Psyche, as you will see.

In front of the chrysalid bag is an abundant mass of extra-fine
wadding, similar to that of which a few flocks used to fall outside on
the occasions when the recluse went to her window. Is it silk? Is it
spun muslin? No; but it is something of incomparable delicacy. The
microscope recognizes it as the scaly dust, the impalpable down in
which every Moth is clad. To give a snug shelter to the little
caterpillars who will soon be swarming in the case, to provide them
with a refuge in which they can play about and gather strength before
entering the wide world, the Psyche has stripped herself of her fur
like the mother Rabbit.

This denudation may be a mere mechanical result, an unintentional
effect of repeated rubbing against the low-roofed walls; but there is
nothing to tell us so. Maternity has its foresight, even among the
humblest. I therefore picture the hairy Moth twisting about, going to
and fro in the narrow passage in order to get rid of the fleece and
prepare bedding for her offspring. It is even possible that she manages
to use her lips, that vestige of a mouth, in order to pull out the down
that refuses to come away of itself.

No matter what the method of shearing may be, a mound of scales and
hairs fills up the case in front of the chrysalid bag. For the moment,
it is a barricade preventing access to the house, which is open at the
hinder end; soon, it will be a downy couch on which the little
caterpillars will rest for a while after leaving the egg. Here, warmly
ensconced in a rug of extreme softness, they call a halt as a
preparation for the emergence and the work that follows it.

Not that silk is lacking: on the contrary, it abounds. The caterpillar
lavished it during his time as a spinner and a picker-up of straws. The
whole interior of the case is padded with thick white satin. But how
greatly preferable to this too-compact and luxurious upholstery is the
delightful eiderdown bedding of the new-born youngsters!

We know the preparations made for the coming family. Now, where are the
eggs? At what spot are they laid? The smallest of my three Psyches, who
is less misshapen than the others and freer in her movements, leaves
her case altogether. She possesses a long ovipositor and inserts it,
through the exit-hole, right into the chrysalid slough, which is left
where it was in the form of a bag. This slough receives the laying.
When the operation is finished and the bag of eggs is full, the mother
dies outside, hanging on to the case.

The two other Psyches, who do not carry telescopic ovipositors and
whose only method of changing their position is a dubious sort of
crawling, have more singular customs to show us. One might quote with
regard to them what used to be said of the Roman matrons, those model
mothers:

“Domi mansit, lanam fecit.”

Yes, lanam fecit. The Psyche does not really work the wool on the
distaff; but at least she bequeathes to her sons her own fleece
converted into a heap of wadding. Yes, domi mansit. She never leaves
her house, not even for her wedding, not even for the purpose of laying
her eggs.

We have seen how, after receiving the visit of the male, the shapeless
Moth, that uncouth sausage, retreats to the back of her case and
withdraws into her chrysalid slough, which she fills exactly, just as
though she had never left it. The eggs are in their place then and
there; they occupy the regulation sack favoured by the various Psyches.
Of what use would a laying be now? Strictly speaking, there is none, in
fact; that is to say, the eggs do not leave the mother’s womb. The
living pouch which has engendered them keeps them within itself.

Soon this bag loses its moisture by evaporation; it dries up and at the
same time remains sticking to the chrysalid wrapper, that firm support.
Let us open the thing. What does the magnifying-glass show us? A few
trachean threads, lean bundles of muscles, nervous ramifications, in
short, the relics of a form of vitality reduced to its simplest
expression. Taken all around, very nearly nothing. The rest of the
contents is a mass of eggs, an agglomeration of germs numbering close
upon three hundred. In a word, the insect is one enormous ovary,
assisted by just so much as enables it to perform its functions.



CHAPTER X

THE PSYCHES: THE CASES


The hatching of the eggs takes place in the first fortnight of July.
The little grubs measure about one twenty-fifth of an inch. Their head
and the upper part of the first thoracic segment are a glossy black,
the next two segments brownish and the rest of the body a pale amber.
Sharp, lively little creatures, who run about with short, quick steps,
they swarm all over the spongy, hairy tissue resulting from the
cast-off clothing of the eggs.

The books tell me that the little Psyches begin by eating up their
mother: a loathsome banquet for which the said books must accept
responsibility. I see nothing of the sort; and I do not even understand
how the idea arose. The mother bequeaths to her sons her case, whose
straws are searched for wadding, the material of the first coat; out of
her chrysalid slough and her skin she makes them a two-fold shelter for
the hatching-time; with her down she prepares a defensive barricade for
them and a place wherein to wait before emerging. Thus all is given,
all spent with a view to the future. Save for some thin, dry strips
which my lens can only with difficulty distinguish, there is nothing
left that could provide a cannibal feast for so numerous a family.

No, my little Psyches, you do not eat your mother. In vain do I watch
you: never, either to clothe or to feed himself, does any one of you
lay a tooth upon the remains of the deceased. The maternal skin is left
untouched, as are those other insignificant relics, the layer of
muscular tissue and the network of air-ducts. The sack left behind by
the chrysalis also remains intact.

The time comes to quit the natal wallet. An outlet has been contrived
long beforehand, saving the youngsters from committing any act of
violence against what was once their mother. There is no sacrilegious
cutting to be done with the shears; the door opens of itself.

When she was a wriggling speck of sausage, the mother’s front segments
were remarkably translucent, forming a contrast with the rest of the
body. This was very probably a sign of a less dense and less tough
texture than elsewhere. The sign is not misleading. The dry gourd to
which the mother is now reduced has for a neck those diaphanous rings,
which, as they withered, became extremely fragile. Does this neck, this
operculum fall of its own accord, or is it pushed off by the pigmies
impatient to get away? I do not know for certain. This, however, I can
say, that blowing on it is enough to make it drop off.

In anticipation therefore of the emergence, an exceedingly easy and
perhaps even spontaneous method of decapitation is prepared in the
mother’s lifetime. To manufacture a delicate neck for yourself so that
you may be easily beheaded at the proper time and thus leave the way
free to the youngsters is an act of devotion in which the most
unconscious maternal affection stands sublimely revealed. That
miserable maggot, that sausage Moth, scarce able to crawl and yet so
clear-sighted where the future is concerned, staggers the mind of any
one who knows how to think.

The brood emerge from the natal wallet through the window just opened
by the fall of the head. The chrysalid sack, the second wrapper,
presents no obstacle; it has remained open since the adult Psyche left
it. Next comes the mass of eiderdown, the heap of fluff of which the
mother stripped herself. Here the little caterpillars stop. Much more
spaciously and comfortably lodged than in the bag whence they have
come, some take a rest, others bustle about, exercise themselves in
walking. All pick up strength in preparation for their exodus into the
daylight.

They do not stay long amid this luxury. Gradually, as they gain vigour,
they come out and spread over the surface of the case. Work begins at
once, a very urgent work, that of the wardrobe. The first mouthfuls
will come afterwards, when we are dressed.

Montaigne, when putting on the cloak which his father had worn before
him, used a touching expression. He said:

“I dress myself in my father.”

The young Psyches in the same way dress themselves in their mother:
they cover themselves with the clothes left behind by the deceased,
they scrape from it the wherewithal to make themselves a cotton frock.
The material employed is the pith of the little stalks, especially of
the pieces which, split lengthwise, are more easily stripped of their
contents. The grub first finds a spot to suit it. Having done so, it
gleans, it planes with its mandibles. Thus a superbly white wadding is
extracted from old logs.

The manner of beginning the garment is worth noting. The tiny creature
employs as judicious a method as any which our own industry could hope
to discover. The wadding is collected in infinitesimal pellets. How are
these little particles to be fixed as and when they are detached by the
shears of the mandibles? The manufacturer needs a support, a base; and
this support cannot be obtained on the caterpillar’s own body, for any
adherence would be seriously embarrassing and would hamper freedom of
movement. The difficulty is overcome very cleverly. Scraps of plush are
gathered and by degrees fastened to one another with threads of silk.
This forms a sort of rectilinear garland in which the particles
collected swing from a common rope. When these preparations are deemed
sufficient, the little creature passes the garland round its waist, at
about the third segment of the thorax, so as to leave its six legs
free; then it ties the two ends with a bit of silk. The result is a
girdle, generally incomplete, but soon completed with other scraps
fastened to the silk ribbon that carries everything.

This girdle is the base of the work, the support. Henceforth, to
lengthen the piece, to enlarge it into the perfect garment, the grub
has only to fix, always at the fore-edge, with the aid of its
spinnerets, now at the top, now at the bottom or side, the scraps of
pith which the mandibles never cease extracting. Nothing could be
better thought out than this initial garland laid out flat and then
buckled like a belt around the loins.

Once this base is laid, the weaving-loom is in full swing. The piece
woven is first a tiny string around the waist; next, by the addition of
fresh pellets, always at the fore-edge, it grows into a scarf, a
waistcoat, a short jacket and lastly a sack, which gradually makes its
way backwards, not of itself, but through the action of the weaver, who
slips forward in the part of the case already made. In a few hours, the
garment is completed. It is by that time a conical hood, a cloak of
magnificent whiteness and finish.

We now know all about it. On leaving the maternal hut, without
searching, without distant expeditions which would be so dangerous at
that age, the little Psyche finds in the tender beams of the roof the
wherewithal to clothe himself. He is spared the perils of roaming in a
state of nudity. When he leaves the house, he will be quite warm,
thanks to the mother, who takes care to instal her family in the old
case and gives it choice materials to work with.

If the grub-worm were to drop out of the hovel, if some gust of wind
swept him to a distance, most often the poor mite would be lost.
Ligneous straws, rich in pith, dry and retted to a turn, are not to be
found everywhere. It would mean the impossibility of any clothing and,
in that dire poverty, an early death. But, if suitable materials are
encountered, equal in quality to those bequeathed by the mother, how is
it that the exile is unable to make use of them? Let us look into this.

I segregate a few new-born grubs in a glass tube and give them for
their materials some split pieces of straw, picked from among the old
stalks of a sort of dandelion, Pterotheca nemausensis. Though robbed of
the inheritance of the maternal manor, the grubs seem very well
satisfied with my bits. Without the least hesitation, they scrape out
of them a superb white pith and make it into a delicious cloak, much
handsomer than that which they would have obtained with the ruins of
the native house, this latter cloak being always more or less flawed
with darker materials, whose colour has been impaired by long exposure
to the air. On the other hand, the Nîmes dandelion, a relic of last
spring, has its central part, which I myself lay bare, a spotless
white; and the cotton nightcap achieves the very perfection of
whiteness.

I obtain an even better result with rounds of sorghum-pith taken from
the kitchen-broom. This time, the work has glittering crystalline
points and looks like a thing built of grains of sugar. It is my
manufacturers’ masterpiece.

These two successes authorize me to vary the raw material still
further. In the absence of new-born caterpillars, who are not always at
my disposal, I employ grubs which I have undressed, that is to say,
which I have taken out of their caps. To these divested ones I give, as
the only thing to work upon, a strip of paper free from paste and easy
to pick to pieces, in short, a piece of blotting-paper.

Here again there is no hesitation. The grubs lustily scrape this
surface, new to them though it be, and make themselves a paper coat of
it. Cadet Roussel, [28] of famous memory, had a coat of similar stuff,
but much less fine and silky. My paper-clad charges are so well-pleased
with their materials that they scorn their native case, when it is
afterwards placed at their disposal, and continue to scrape lint from
the industrial product.

Others are given nothing in their tube, but are able to get at the cork
that closes the glass dwelling-house. This is enough. The undraped ones
hasten to scrape the cork, to break it into atoms and out of these to
make themselves a granulated frock, as faultlessly elegant as though
their race had always made use of this material. The novelty of the
stuff, employed perhaps for the first time, has made no change in the
cut of the coat.

To sum up, they accept any vegetable matter that is dry, light and not
too resistant. Would they behave likewise towards animal materials and
especially mineral materials, on condition that these are of a suitable
thinness? I take a Great Peacock’s wing, left over from my experiments
in the nuptial telegraphy of this Moth, [29] and cut from it a strip on
which I place, at the bottom of a tube, two little caterpillars
stripped of their clothing. The two prisoners have nothing else at
their disposal. Any drapery that they want must be got out of this
scaly expanse.

They hesitate for a long time in the presence of that strange carpet.
In twenty-four hours’ time, one of the caterpillars has started no work
and seems resolved to let himself die, naked as he is. The other,
stouter-hearted, or perhaps less injured by the brutal
stripping-process, explores the slip for a little while and at last
resolves to make use of it. Before the day is over, he has clothed
himself in grey velvet out of the Great Peacock’s scales. Considering
the delicacy of the materials, the work is exquisitely correct.

Let us go a step farther in our explorations. For the soft, yielding
wadding collected from a plant, or the down gleaned from the wing of a
Moth, we will substitute rough stone. In their final state, I know, the
Psyches’ cases are often laden with grains of sand and earthy
particles; but these are accidental bricks, which have been
inadvertently touched by the spinneret and incorporated unintentionally
in the thatch. The delicate creatures know too well the drawbacks of a
pebbly pillow to seek the support of stone. Mineral matter is
distasteful to them; and it is mineral matter that now has to be worked
like wool.

True, I select such stones in my collection as are least out of keeping
with the feeble powers of my grubs. I possess a specimen of flaky
hematite. At the merest touch of a hair-pencil it breaks into atoms
almost as minute as the dust which a Butterfly’s wing leaves on our
fingers. On a bed of this material, which glitters like a steel filing,
I establish four young caterpillars extracted from their clothing. I
foresee a check in this experiment and consequently increase the number
of my subjects.

It is as I thought. The day passes and the four caterpillars remain
bare. Next day, however, one, one alone, decides to clothe himself. His
work is a tiara with metallic facets, in which the light plays with
flashes of every colour of the rainbow. It is very rich, very
sumptuous, but mightily heavy and cumbrous. Walking becomes laborious
under that load of metal. Even so must a Byzantine emperor have
progressed at ceremonies of state, after donning his gold-worked
dalmatic.

Poor little creature! More sensible than man, you did not select that
ridiculous magnificence of your own free will; it was I who forced it
on you. Here, to make amends, is a disk of sorghum-pith. Fling off your
proud tiara, thrust it from you quickly and place in its stead a cotton
night-cap, which is much healthier. This is done on the second day.

The Psyche has his favourite materials when starting as a manufacturer:
a vegetable lint collected from any ligneous scrap well softened by the
air, a lint usually supplied by the old roof of the maternal hut. In
the absence of the regulation fabric, he is able to make use of animal
velvet, in particular of the scaly fluff of a Moth. In case of
necessity, he does not shrink from acts of sheer madness: he weaves
mineral matter, so urgent is his need to clothe himself.

This need outweighs that of nourishment. I take a young caterpillar
from his grazing-ground, a leaf of very hairy hawkweed which, after
many attempts, I have found to suit him as food because of its green
blade and as wool because of its white fleece. I take him, I say, from
his refectory and leave him to fast for a couple of days. Then I strip
him and put him back on his leaf. And I see him, unmindful of eating,
in spite of his long fast, first labouring to make himself a new coat
by collecting the hairs of the hawkweed. His appetite will be satisfied
afterwards.

Is he then so susceptible to cold? We are in the midst of the dog-days.
The sun shoots down a fiery torrent that brings the wild concert of the
Cicadæ up to fever-pitch. In the baking heat of the study where I am
questioning my animals, I have flung off hat and necktie and am working
in my shirt-sleeves; and, in this oven, what the Psyche clamours for
is, above all things, a warm covering. Well, little shiverer, I will
satisfy you!

I expose him to the direct rays of the sun, on the window-ledge. This
time, it is too much of a good thing; I have gone beyond all bounds.
The sun-scorched one wriggles about, flourishes his abdomen, always a
sign of discomfort. But the making of the hawkweed cassock is not
suspended on this account; on the contrary, it is pursued more
hurriedly than ever. Could this be because of the excessive light? Is
not the cotton-wool bag a retreat wherein the caterpillar isolates
himself, sheltering from the importunities of broad daylight, and
gently digests and sleeps? Let us get rid of the light, while retaining
a warm temperature.

After a preliminary stripping, the little caterpillars are now lodged
in a cardboard box, which I place in the sunniest corner of my window.
The temperature here is well over 100° F. No matter: the swan’s-down
sack is remade at a sitting of a few hours. Tropical heat and the quiet
that goes with darkness have made no difference in the insect’s habits.

Neither the degree of heat nor the degree of light explains the
pressing need of raiment. Where are we to seek the reason for that
hurry to get clad? I can see none save a presentiment of the future.
The Psyche caterpillar has the winter before him. He knows nothing of a
common shelter in a silken purse, of cabins among close-touching
leaves, of underground cells, of retreats under old cracked bark, of
hairy roofs, of cocoons, in short of the different methods employed by
other caterpillars to protect themselves against the severity of the
weather. He has to spend the winter exposed to the inclemencies of the
air. This peril causes his particular talent.

He builds himself a roof whose imbricated and diverging stalks will
allow cold dews and drops of melted snow to trickle away at a distance,
when the case is fixed and hanging vertically. Under this covering, he
weaves a thick silk lining, which will make a soft mattress and a
rampart against the effects of the cold. Once these precautions are
taken, the winter may come and the north wind rage: the Psyche is
sleeping peacefully in his hut.

But all this is not improvised as the stormy season approaches. It is a
delicate work which takes time to carry out. All his life-long the
caterpillar labours at it, improving it, adding to it, strengthening it
incessantly. And, in order to acquire greater skill, he begins his
apprenticeship at the moment when he leaves the egg. As preliminary
practice for the thick overcoat of full-grown age, he tries his hand on
cotton capes. Even so does the Pine Processionary, as soon as hatched,
weave first delicate tents, then gauzy cupolas, as harbingers of the
mighty wallet in which the community will make its home. Both alike are
harassed from the day of their birth by the presentiment of the future;
they start life by binding themselves apprentices to the trade that is
to safeguard them one day.

No, the Psyche is not more sensitive to cold than any other
smooth-skinned caterpillar; he is a creature of foresight. Deprived in
winter of the shelters granted to the others, he prepares himself, from
his birth, for the building of a home that will be his salvation and
practises for it by making fripperies of wadding suited to his
strength. He foresees the rigours of winter during the blazing
dog-days.

They are now all clad, my young caterpillars, numbering nearly a
thousand. They wander restlessly in large glass receptacles, closed
with a sheet of glass. What do you seek, little ones, swinging your
pretty, snow-white cloaks as you go? Food, of course. After all that
fatigue, you need refreshment. Despite your numbers, you will not be
too heavy a burden on my resources: you can manage with so little! But
what do you ask for? You certainly do not count on me for your
supplies. In the open fields you would have found victuals to your
liking much more easily than I can hope to find them for you. Since my
wish to know all about you places you in my charge, I have a duty which
I must observe: that of feeding you. What do you want?

The part of Providence is a very difficult one to play. The purveyor of
foodstuffs, thinking of the morrow, taking his precautions so that the
home may be always more or less supplied, performs the most deserving
but also the most laborious of functions. The little ones wait
trustingly, persuaded that things happen of themselves, while he
anxiously resorts to every kind of ingenuity and trouble, wondering
whether the right thing will come. Ah, how well long practice has
taught me to know the trade, with all its worries and all its joys!

Behold me to-day the Providence of a thousand nurselings thrust upon me
by my studies. I try a little of everything. The tender leaves of the
elm appear to suit. If I serve them up one day, I find them next
morning nibbled on the surface, in small patches. Tiny grains of
impalpable black dust, scattered here and there, tell me that the
intestines have been at work. This gives me a moment of satisfaction
which will be readily understood by any breeder of a herd whose diet is
unknown. The hope of success gains strength: I know how to feed my
vermin. Have I discovered the best method at the first attempt? I dare
not think so.

I continue therefore to vary the fare, but the results hardly come up
to my wishes. The flock refuses my assorted green stuff and even ends
by taking a dislike to the elm-leaves. I am beginning to believe that I
have failed utterly, when a happy inspiration occurs to me. I have
recognized among the bits that go to form the case a few fragments of
the mouse-ear hawkweed (Hieracium pilosella). So the Psyche frequents
that plant. Why should he not browse it? Let us try.

The mouse-ear displays its little round flowers in profusion in a stony
field just beside my house, at the foot of the wall where I have so
often found Psyche-cases hanging. I gather a handful and distribute it
among my different folds. This time the food-problem is solved. The
Psyches forthwith settle in solid masses on the hairy leaves and nibble
at them greedily in small patches, in which the epidermis of the other
surface remains untouched.

We will leave them to their grazing, with which they seem quite
satisfied, and ask ourselves a certain question relating to
cleanliness. How does the little Psyche get rid of his digestive
refuse? Remember that he is enclosed in a sack. One dare not entertain
the thought of ordure ejected and accumulating at the far end of the
dazzling white plush cap. Filth cannot dwell under so elegant a
covering. How is the sordid evacuation managed?

Despite the fact that it ends in a conical point, in which the lens
reveals no break of continuity, the sack is not closed at the hinder
end. Its method of manufacture, by means of a waistband whose fore-edge
increases in dimensions in proportion as the rear-edge is pushed
farther back, proves this sufficiently. The hinder end becomes pointed
simply owing to the shrinking of the material, which contracts of
itself at the part where the caterpillar’s decreasing diameter no
longer distends it. There is thus at the point a permanent hole whose
lips remain closed. The caterpillar has only to go a little way back
and the stuff expands, the hole widens, the road is open and the
excretions fall to the ground. On the other hand, so soon as the
caterpillar takes a step forward into his case, the rubbish-shoot
closes of itself. It is a very simple and very ingenious mechanism, as
good as anything contrived by our seamstresses to cope with the
shortcomings of a boy’s first pair of breeches.

Meanwhile the grub grows and its tunic continues to fit it, is neither
too large nor too small, but just the right size. How is this done? If
the text-books were to be credited, I might expect to see the
caterpillar split his sheath lengthwise when it became too tight and
afterwards enlarge it by means of a piece woven between the edges of
the rent. That is what our tailors do; but it is not the Psyches’
method at all. They know something much better. They keep on working at
their coat, which is old at the back, new in front and always a perfect
fit for the growing body.

Nothing is easier than to watch the daily progress in size. A few
caterpillars have just made themselves a hood of sorghum-pith. The work
is perfectly beautiful; it might have been woven out of snow-flakes. I
isolate these smartly-dressed ones and give them as weaving-materials
some brown scales chosen from the softest parts that I can find in old
bark. Between morning and evening, the hood assumes a new appearance:
the tip of the cone is still a spotless white, but all the front part
is coarse drapery, very different in colouring from the original plush.
Next day, the sorghum felt has wholly disappeared and is replaced, from
one end of the cone to the other, by a frieze of bark.

I then take away the brown materials and put sorghum-pith in their
stead. This time the coarse, dark stuff retreats gradually towards the
top of the hood, while the soft, white stuff gains in width, starting
from the mouth. Before the day is over, the original elegant mitre will
be reconstructed entirely.

This alternation can be repeated as often as we please. Indeed, by
shortening each period of work, we can easily obtain, with the two
sorts of material, composite products, showing alternate light and dark
belts.

The Psyche, as you see, in no way follows the methods of our tailors,
with their piece taken out and another piece let in. In order to have a
coat always to his size, he never ceases working at it. The particles
collected are constantly being fixed just at the edge of the sack, so
that the new drapery increases progressively in dimensions, keeping
pace with the caterpillar’s growth. At the same time the old stuff
recedes, is driven back towards the tip of the cone. Here, through its
own springiness, it contracts and closes the muff. Any surplus matter
disintegrates, falls into shreds and gradually disappears as the insect
roams about and knocks against the things which it meets. The case, new
at the front and old at the back, is never too tight because it is
always being renewed.

After the very hot period of the year, there comes a moment when light
wraps are no longer seasonable. Autumnal rains threaten, followed by
winter frosts. It is time to make ourselves a thick great-coat with a
cape of thatch arranged in a series of waterproof tippets. It begins
with a great lack of accuracy. Straws of uneven length and bits of dry
leaves are fastened, with no attempt at order, behind the neck of the
sack, which must still retain its flexibility so as to allow the
caterpillar to bend freely in every direction.

Few as yet, rather short and placed anyhow, sometimes lengthways and
sometimes across, these untidy first logs of the roof will not
interfere with the final regularity of the building: they are destined
to disappear and will be pushed back and be driven out at last as the
sack grows in front.

Later on, when the pieces are longer and better-chosen, they are all
carefully laid longitudinally. The placing of a straw is done with
surprising quickness and dexterity. If the log which he has found suits
him, the caterpillar takes it between his legs and turns it round and
round. Gripping it with his mandibles by one end, as a rule he removes
a few morsels from this part and immediately fixes them to the neck of
the sack. His object in laying bare the raw and rough surfaces, to
which the silk will stick better, may be to obtain a firmer hold. Even
so the plumber gives a touch of the file at the point that is to be
soldered.

Then, by sheer strength of jaw, the caterpillar lifts his beam,
brandishes it in the air and, with a quick movement of his rump, lays
it on his back. The spinneret at once sets to work on the end caught.
And the thing is done: without any groping about or correcting, the log
is added to the others, in the direction required.

The fine days of autumn are spent in toil of this kind, performed
leisurely and intermittently, when the stomach is full. By the time
that the cold weather arrives, the house is ready. When the air is once
more warm, the Psyche resumes his walks abroad: he roams along the
paths, strolls over the friendly greensward, takes a few mouthfuls and
then, when the hour has come, prepares for his transformation by
hanging from the wall.

These springtime wanderings, long after the case is completely
finished, made me want to know if the caterpillar would be capable of
repeating his sack-weaving and roof-building operations. I take him out
of his case and place him, stark naked, on a bed of fine, dry sand. I
give him as materials to work with some old stalks of Nîmes dandelion,
cut up into sticks of the same length as the pieces that make the case.

The evicted insect disappears under the heap of ligneous straws and
hurriedly starts spinning, taking as pegs for its cords anything that
its lips encounter: the bed of sand underfoot, the canopy of twigs
overhead. So doing, it binds together, in extricable confusion, all the
pieces touched by the spinneret, long and short, light and heavy, at
random. In the centre of this tangled scaffolding, a work is pursued of
a quite different nature from that of hut-building. The caterpillar
weaves and does nothing else, not even attempting to assemble into a
proper roofing the materials of which he is able to dispose.

The Psyche owning a perfect case, when he resumes his activity with the
fine weather, scorns his old trade as an assembler of logs, a trade
practised so zealously during the previous summer. Now that his stomach
is satisfied and his silk-glands distended, he devotes his spare time
solely to improving the quilting of his case. The silky felt of the
interior is never thick or soft enough to please him. The thicker and
softer it is, the better for his own comfort during the process of
transformation and for the safety of his family afterwards.

Well, my knavish tricks have now robbed him of everything. Does he
perceive the disaster? Though the silk and timber at his disposal
permit, does he dream of rebuilding the shelter, so essential first to
his chilly back and secondly to his family, who will cut it up to make
their first home? Not a bit of it. He slips under the mass of twigs
where I let it fall and there begins to work exactly as he would have
done under normal conditions.

This shapeless roof and this sand on which the jumble of rafters are
lying now represent to the Psyche the walls of the regulation home;
and, without in any way modifying his labours to meet the exigencies of
the moment, the caterpillar upholsters the surfaces within his reach
with the same zest that he would have displayed in adding new layers to
the quilted lining which has disappeared. Instead of being pasted on
the proper wall, the present hangings come in contact with the rough
surface of the sand and the hopeless tangle of the straws; and the
spinner takes no notice.

The house is worse than ruined: it no longer exists. No matter: the
caterpillar continues his actual work; he loses sight of the real and
upholsters the imaginary. [30] And yet everything ought to apprise him
of the absence of any roofing. The sack with which he has managed to
cover himself, very skilfully for that matter, is lamentably flabby. It
sags and rumples at every movement of the insect’s body. Moreover, it
is made heavy with sand and bristles with spikes in every direction,
which catch in the dust of the road and make all progress impossible.
Thus anchored to the ground, the caterpillar wastes his strength in
efforts to shift his position. It takes him hours to make a start and
to move his cumbrous dwelling a fraction of an inch.

With his normal case, in which all the beams are imbricated from front
to back with scientific precision, he gets along very nimbly. His
collection of logs, all fixed in front and all free at the back, forms
a boat-shaped sledge which slips and glides through obstacles without
difficulty. But, though progress be easy, retreat is impracticable, for
each piece of the framework causes the thing to stop, owing to its free
end.

Well, the sack of my victim is covered with laths pointing this way and
that, just in the position in which they happened to be caught by the
spinneret, as it fastened its threads here and there, indiscriminately.
The bits in front are so many spurs which dig into the sand and
neutralize all efforts to advance; the bits at the side are rakes whose
resistance cannot be overcome. In such conditions, the insect is bound
to be stranded and to perish on the spot.

If I were advising the caterpillar, I should say:

“Go back to the art in which you excel; arrange your bundle neatly;
point the cumbrous pieces lengthwise, in an orderly fashion; do
something to your sack, which hangs too loosely; give it the necessary
stiffness with a few props to act as a busk; do now, in your distress,
what you knew so well how to do before; summon up your old
carpentering-talents and you will be saved.”

Useless advice! The time for carpentry is over. The hour has come for
upholstering; and he upholsters obstinately, padding a house which no
longer exists. He will perish miserably, cut up by the Ants, as the
result of his too-rigid instinct.

Many other instances have already told us as much. Like running water
which does not climb slopes and which does not flow back to its source,
the insect never retraces its actions. What is done is done and cannot
be recommenced. The Psyche, but now a clever carpenter, will die for
want of knowing how to fix a beam.



CHAPTER XI

THE GREAT PEACOCK


It was a memorable evening. I shall call it the Great Peacock evening.
Who does not know the magnificent Moth, the largest in Europe, clad in
maroon velvet with a necktie of white fur? The wings, with their
sprinkling of grey and brown, crossed by a faint zig-zag and edged with
smoky white, have in the centre a round patch, a great eye with a black
pupil and a variegated iris containing successive black, white,
chestnut and purple arcs.

No less remarkable is the caterpillar, in colour an undecided yellow.
On the top of thinly-scattered tubercles, crowned with a palisade of
black hairs, are set beads of turquoise blue. His stout brown cocoon,
so curious with its exit-shaft shaped like an eel-trap, is usually
fastened to the bark at the base of old almond-trees. The caterpillar
feeds on the leaves of the same tree.

Well, on the morning of the 6th of May, a female emerges from her
cocoon in my presence, on the table of my insect-laboratory. I
forthwith cloister her, still damp with the humours of the hatching,
under a wire-gauze bell-jar. For the rest, I cherish no particular
plans. I incarcerate her from mere habit, the habit of the observer
always on the look-out for what may happen.

It was a lucky thought. At nine o’clock in the evening, just as the
household is going to bed, there is a great stir in the room next to
mine. Little Paul, half-undressed, is rushing about, jumping and
stamping, knocking the chairs over like a mad thing. I hear him call
me:

“Come quick!” he screams. “Come and see these Moths, big as birds! The
room is full of them!”

I hurry in. There is enough to justify the child’s enthusiastic and
hyperbolical exclamations, an invasion as yet unprecedented in our
house, a raid of giant Moths. Four are already caught and lodged in a
bird-cage. Others, more numerous, are fluttering on the ceiling.

At this sight, the prisoner of the morning is recalled to my mind.

“Put on your things, laddie,” I say to my son. “Leave your cage and
come with me. We shall see something interesting.”

We run downstairs to go to my study, which occupies the right wing of
the house. In the kitchen I find the servant, who is also bewildered by
what is happening and stands flicking her apron at great Moths whom she
took at first for Bats.

The Great Peacock, it would seem, has taken possession of pretty well
every part of the house. What will it be around my prisoner, the cause
of this incursion? Luckily, one of the two windows of the study had
been left open. The approach is not blocked.

We enter the room, candle in hand. What we see is unforgetable. With a
soft flick-flack the great Moths fly around the bell-jar, alight, set
off again, come back, fly up to the ceiling and down. They rush at the
candle, putting it out with a stroke of their wings; they descend on
our shoulders, clinging to our clothes, grazing our faces. The scene
suggests a wizard’s cave, with its whirl of Bats. Little Paul holds my
hand tighter than usual, to keep up his courage.

How many of them are there? About a score. Add to these the number that
have strayed into the kitchen, the nursery and the other rooms of the
house; and the total of those who have arrived from the outside cannot
fall far short of forty. As I said, it was a memorable evening, this
Great Peacock evening. Coming from every direction and apprised I know
not how, here are forty lovers eager to pay their respects to the
marriageable bride born that morning amid the mysteries of my study.

For the moment let us disturb the swarm of wooers no further. The flame
of the candle is a danger to the visitors, who fling themselves into it
madly and singe their wings. We will resume the observation tomorrow
with an experimental interrogatory thought out beforehand.

But first let us clear the ground and speak of what happens every night
during the week that my observation lasts. Each time it is pitch dark,
between eight and ten o’clock, when the Moths arrive one by one. It is
stormy weather, the sky is very much overcast and the darkness is so
profound that even in the open air, in the garden, far from the shadow
of the trees, it is hardly possible to see one’s hand before one’s
face.

In addition to this darkness there is the difficulty of access. The
house is hidden by tall plane-trees; it is approached by a walk thickly
bordered with lilac- and rose-trees, forming a sort of outer vestibule;
it is protected against the mistral by clumps of pines and screens of
cypresses. Clusters of bushy shrubs make a rampart a few steps away
from the door. It is through this tangle of branches, in complete
darkness, that the Great Peacock has to tack about to reach the object
of his pilgrimage.

Under such conditions, the Brown Owl would not dare leave the hole in
his olive-tree. The Moth, better-endowed with his faceted optical
organs than the night-bird with its great eyes, goes forward without
hesitating and passes through without knocking against things. He
directs his tortuous flight so skilfully that, despite the obstacles
overcome, he arrives in a state of perfect freshness, with his big
wings intact, with not a scratch upon him. The darkness is light enough
for him.

Even if we grant that it perceives certain rays unknown to common
retinæ, this extraordinary power of sight cannot be what warns the Moth
from afar and brings him hurrying to the spot. The distance and the
screens interposed make this quite impossible.

Besides, apart from deceptive refractions, of which there is no
question in this case, the indications provided by light are so precise
that we go straight to the thing seen. Now the Moth sometimes blunders,
not as to the general direction which he is to take, but as to the
exact spot where the interesting events are happening. I have said that
the children’s nursery, which is at the side of the house opposite my
study, the real goal of my visitors at the present moment, was occupied
by the Moths before I went there with a light in my hand. These
certainly were ill-informed. There was the same throng of hesitating
visitors in the kitchen; but here the light of a lamp, that
irresistible lure to nocturnal insects, may have beguiled the eager
ones.

Let us consider only the places that were in the dark. In these there
are several stray Moths. I find them more or less everywhere around the
actual spot aimed at. For instance, when the captive is in my study,
the visitors do not all enter by the open window, the safe and direct
road, only two or three yards away from the caged prisoner. Several of
them come in downstairs, wander about the hall and at most reach the
staircase, a blind alley barred at the top by a closed door.

These data tell us that the guests at this nuptial feast do not make
straight for their object, as they would if they derived their
information from some kind of luminous radiation, whether known or
unknown to our physical science. It is something else that apprises
them from afar, leads them to the proximity of the exact spot and then
leaves the final discovery to the airy uncertainty of random searching.
It is very much like the way in which we ourselves are informed by
hearing and smell, guides which are far from accurate when we want to
decide the precise point of origin of the sound or the smell.

What are the organs of information that direct the rutting Moth on his
nightly pilgrimage? One suspects the antennæ, which, in the males, do
in fact seem to be questioning space with their spreading tufts of
feathers. Are those glorious plumes mere ornaments, or do they at the
same time play a part in the perception of the effluvia that guide the
enamoured swain? A conclusive experiment seems to present no
difficulty. Let us try it.

On the day after the invasion, I find in the study eight of my visitors
of the day before. They are perched motionless on the transoms of the
second window, which is kept closed. The others, when their dance was
over, about ten o’clock in the evening, went out as they came in, that
is to say, through the first window, which is left open day and night.
Those eight persevering ones are just what I want for my schemes.

With a sharp pair of scissors, without otherwise touching the Moths, I
cut off their antennæ, near the base. The patients take hardly any
notice of the operation. Not one moves; there is scarcely a flutter of
the wings. These are excellent conditions: the wound does not seem at
all serious. Undistraught by pain, the Moths bereft of their horns will
adapt themselves all the better to my plans. The rest of the day is
spent in placid immobility on the cross-bars of the window.

There are still a few arrangements to be made. It is important in
particular to shift the scene of operations and not to leave the female
before the eyes of the maimed ones at the moment when they resume their
nocturnal flight, else the merit of their quest would disappear. I
therefore move the bell-jar with its captives and place it under a
porch at the other end of the house, some fifty yards from my study.

When night comes, I go to make a last inspection of my eight victims.
Six have flown out through the open window; two remain behind, but
these have dropped to the floor and no longer have the strength to turn
over if I lay them on their backs. They are exhausted, dying. Pray do
not blame my surgical work. This quick decreptitude occurs invariably,
even without the intervention of my scissors.

Six, in better condition, have gone off. Will they return to the bait
that attracted them yesterday? Though deprived of their antennæ, will
they be able to find the cage, now put in another place, at a
considerable distance from its original position?

The cage is standing in the dark, almost in the open air. From time to
time, I go out with a lantern and a Butterfly-net. Each visitor is
captured, examined, catalogued and forthwith let loose in an adjoining
room, of which I close the door. This gradual elimination will enable
me to tell the exact number, with no risk of counting the same Moth
more than once. Moreover, the temporary gaol, which is spacious and
bare, will in no way endanger the prisoners, who will find a quiet
retreat there and plenty of room. I shall take similar precautions
during my subsequent investigations.

At half past ten no more arrive. The sitting is over. In all,
twenty-five males have been caught, of whom only one was without
antennæ. Therefore, of the six on whom I operated yesterday and who
were hale enough to leave my study and go back to the fields, one alone
has returned to the bell-jar. It is a poor result, on which I dare not
rely when it comes to asserting or denying that the antennæ play a
guiding part. We must begin all over again, on a larger scale.

Next morning I pay a visit to the prisoners of the day before. What I
see is not encouraging. Many are spread out on the floor, almost
lifeless. Several of them give hardly a sign of life when I take them
in my fingers. What can I hope from these cripples? Still, let us try.
Perhaps they will recover their vigour when the time comes to dance the
lovers’ round.

The twenty-four new ones undergo amputation of the antennæ. The old,
hornless one is left out of count, as dying or close to it. Lastly, the
prison-door is left open for the remainder of the day. He who will may
leave the room, he who can shall join in the evening festival. In order
to put such as go out to the test of searching for the bride, the cage,
which they would be sure to notice on the threshold, is once more
removed. I shift it to a room in the opposite wing, on the
ground-floor. The access to this room is of course left free.

Of the twenty-four deprived of their antennæ, only sixteen go outside.
Eight remain, powerless to move. They will soon die where they are. Out
of the sixteen who have left, how many are there that return to the
cage in the evening? Not one! I sit up to capture just seven, all
newcomers, all sporting feathers. This result would seem to show that
the amputation of the antennæ is a rather serious matter. Let us not
draw conclusions yet: a doubt remains and an important one.

“A nice state I’m in!” said Mouflard, the Bull-pup, when his pitiless
breeder had docked his ears. “How dare I show my face before the other
Dogs?”

Can it be that my Moths entertain Master Mouflard’s apprehensions? Once
deprived of their fine plumes, dare they no longer appear amidst their
rivals and a-wooing go? Is it bashfulness on their part or lack of
guidance? Or might it not rather be exhaustion after a wait that
exceeds the duration of an ephemeral flame? Experiment shall tell us.

On the fourth evening, I take fourteen Moths, all new ones, and
imprison them, as they arrive, in a room where I intend them to pass
the night. Next morning, taking advantage of their daytime immobility,
I remove a little of the fur from the centre of their corselet. The
silky fleece comes off so easily that this slight tonsure does not
inconvenience the insects at all; it deprives them of no organ which
may be necessary to them later, when the time comes to find the cage.
It means nothing to the shorn ones; to me it means the unmistakable
sign that the callers have repeated their visit.

This time there are no weaklings incapable of flight. At night, the
fourteen shaven Moths escape into the open. Of course the place of the
cage is once more changed. In two hours, I capture twenty Moths,
including two tonsured ones, no more. Of those who lost their antennæ
two days ago, not one puts in an appearance. Their nuptial time is over
for good and all.

Only two return out of the fourteen marked with a bald patch. Why do
the twelve others hang back, although supplied with what we have
assumed to be their guides, their antennary plumes? Why again that
formidable list of defaulters, which we find nearly always after a
night of sequestration? I perceive but one reply: the Great Peacock is
quickly worn out by the ardours of pairing-time.

With a view to his wedding, the one and only object of his life, the
Moth is gifted with a wonderful prerogative. He is able to discover the
object of his desire in spite of distance, obstacles and darkness. For
two or three evenings, he is allowed a few hours wherein to indulge his
search and his amorous exploits. If he cannot avail himself of them,
all is over: the most exact of compasses fails, the brightest of lamps
expires. What is the use of living after that? Stoically we withdraw
into a corner and sleep our last sleep, which is the end of our
illusions and of our woes alike.

The Great Peacock becomes a Moth only in order to perpetuate his
species. He knows nothing of eating. While so many others, jolly
companions one and all, flit from flower to flower, unrolling the
spiral of their proboscis and dipping it into the honeyed cups, he, the
incomparable faster, wholly freed from the bondage of the belly, has no
thought of refreshment. His mouth-parts are mere rudiments, vain
simulacra, not real organs capable of performing their functions. Not a
sup enters his stomach: a glorious privilege, save that it involves a
brief existence. The lamp needs its drop of oil, if it is not to be
extinguished. The Great Peacock renounces that drop, but at the same
time he renounces long life. Two or three evenings, just time enough to
allow the couple to meet, and that is all: the big Moth has lived.

Then what is the meaning of the staying away of those who have lost
their antennæ? Does it show that the absence of these organs has made
them incapable of finding the wire bell in which the prisoner awaits
them? Not at all. Like the shorn ones, whose operation has left them
uninjured, they prove only that their time is up. Whether maimed or
intact, they are unfit for duty because of their age; and their
non-return is valueless as evidence. For lack of the time necessary for
experimenting, the part played by the antennæ escapes us. Doubtful it
was and doubtful it remains.

My caged prisoner lives for eight days. Every evening she draws for my
benefit a swarm of visitors, in varying numbers, now to one part of the
house, now to another, as I please. I catch them, as they come, with
the net and transfer them, the moment they are captured, to a closed
room, in which they spend the night. Next morning, I mark them with a
tonsure on the thorax.

The aggregate of the visitors during those eight evenings amounts to a
hundred and fifty, an astounding number when I consider how hard I had
to seek during the following two years to collect the materials
necessary for continuing these observations. Though not impossible to
find in my near neighbourhood, the cocoons of the Great Peacock are at
least very rare, for old almond-trees, on which the caterpillars live,
are scarce in these parts. For two winters I visited every one of those
decayed trees at the lower part of the trunk, under the tangle of hard
grasses in which they are clad, and time after time I returned
empty-handed. Therefore my hundred and fifty Moths came from afar, from
very far, within a radius of perhaps a mile and a half or more. How did
they know of what was happening in my study?

The perceptive faculties can receive information from a distance by
means of three agents: light, sound and smell. Is it permissible to
speak of vision in this instance? I will readily admit that sight
guides the visitors once they have passed through the open window. But
before that, in the mystery out of doors! It would not be enough to
grant them the fabulous eye of the Lynx, which was supposed to see
through walls; we should have to admit a keenness of sight which could
be exercised miles away. It is useless to discuss anything so
outrageous; let us pass on.

Sound is likewise out of the question. The great fat Moth, capable of
sending a summons to such a distance, is mute even to the most acute
hearing. It is just possible that she possesses delicate vibrations,
passionate quivers, which might perhaps be perceptible with the aid of
an extremely sensitive microphone; but remember that the visitors have
to be informed at considerable distances, thousands of yards away.
Under these conditions, we cannot waste time thinking of acoustics.
That would be to set silence the task of waking the surrounding air.

There remains the sense of smell. In the domain of our senses, scent,
better than anything else, would more or less explain the onrush of the
Moths, even though they do not find the bait that allures them until
after a certain amount of hesitation. Are there, in point of fact,
effluvia similar to what we call odour, effluvia of extreme subtlety,
absolutely imperceptible to ourselves and yet capable of impressing a
sense of smell better-endowed than ours? There is a very simple
experiment to be made. It is a question of masking those effluvia, of
stifling them under a powerful and persistent odour, which masters the
olfactory sense entirely. The too-strong scent will neutralize the very
faint one.

I begin by sprinkling naphthaline in the room where the males will be
received this evening. Also, in the bell-jar, beside the female, I lay
a big capsule full of the same stuff. When the visiting-hour comes, I
have only to stand in the doorway of the room to get a distinct smell
of gas-works. My artifice fails. The Moths arrive as usual, they enter
the room, pass through its tarry atmosphere and make for the cage with
as much certainty of direction as though in unscented surroundings.

My confidence in the olfactory explanation is shaken. Besides, I am now
unable to go on. Worn out by her sterile wait, my prisoner dies on the
ninth day, after laying her unfertilized eggs on the wirework of the
cage. In the absence of a subject of experiment, there is no more to be
done until next year.

This time I shall take my precautions, I shall lay in a stock so as to
be able to repeat as often as I wish the experiments which I have
already tried and those which I am contemplating. To work, then; and
that without delay.

In the summer, I proclaim myself a buyer of caterpillars at a sou
apiece. The offer appeals to some urchins in the neighbourhood, my
usual purveyors. On Thursdays, emancipated from the horrors of parsing,
[31] they scour the fields, find the fat caterpillar from time to time
and bring him to me clinging to the end of a stick. They dare not touch
him, poor mites; they are staggered at my audacity when I take him in
my fingers as they might take the familiar Silk-worm.

Reared on almond-tree branches, my menagerie in a few days supplies me
with magnificent cocoons. In the winter, assiduous searches at the foot
of the fostering tree complete my collection. Friends interested in my
enquiries come to my assistance. In short, by dint of trouble, much
running about, commercial bargains and not a few scratches from
brambles, I am the possessor of an assortment of cocoons, of which
twelve, bulkier and heavier than the others, tell me that they belong
to females.

A disappointment awaits me, for May arrives, a fickle month which
brings to naught my preparations, the cause of so much anxiety. We have
winter back again. The mistral howls, tears the budding leaves from the
plane-trees and strews the ground with them. It is as cold as in
December. We have to light the fires again at night and resume the
thick clothes which we were beginning to leave off.

My Moths are sorely tried. They hatch late and are torpid. Around my
wire cages, in which the females wait, one to-day, another to-morrow,
according to the order of their birth, few males or none come from the
outside. And yet there are some close at hand, for the plumed gallants
resulting from my harvest were placed out in the garden as soon as they
were hatched and recognized. Whether near neighbours or strangers from
afar, very few arrive; and these are only half-hearted. They enter for
a moment, then disappear and do not return. The lovers have grown cold.

It is also possible that the low temperature is unfavourable to the
tell-tale effluvia, which might well be enhanced by the warmth and
decreased by the cold, as happens with scents. My year is lost. Oh,
what laborious work is this experimenting at the mercy of the sudden
changes and deceptions of a short season!

I begin all over again, for the third time. I rear caterpillars, I
scour the country in search of cocoons. When May returns, I am suitably
provided. The weather is fine and responds to my hopes. I once more see
the incursions which had struck me so powerfully at the beginning, at
the time of the historic invasion which first led to my researches.

Nightly the visitors turn up, in squads of twelve, twenty or more. The
female, a lusty, big-bellied matron, clings firmly to the trellis-work
of the cage. She makes no movement, gives not so much as a flutter of
the wings, seems indifferent to what is going on. Nor is there any
odour, so far as the most sensitive nostrils in the household can
judge, nor any rustle perceptible to the most delicate hearing among my
family, all of whom are called in to bear evidence. In motionless
contemplation she waits.

The others, in twos or threes or more, flop down upon the dome of the
cage, run about it briskly in every direction, lash it with the tips of
their wings in continual movement. There are no affrays between rivals.
With not a sign of jealousy in regard to the other suitors, each does
his utmost to enter the enclosure. Tiring of their vain attempts, they
fly away and join the whirling throng of dancers. Some, giving up all
hope, escape through the open window; fresh arrivals take their places;
and, on the top of the cage, until ten o’clock in the evening, attempts
to approach are incessantly renewed, soon to be abandoned and as soon
resumed.

Every evening the cage is moved to a different place. I put it on the
north side and the south, on the ground-floor and the first floor, in
the right wing and fifty yards away in the left, in the open air or
hidden in a distant room. All these sudden displacements, contrived if
possible to put the seekers off the scent, do not trouble the Moths in
the least. I waste my time and ingenuity in trying to deceive them.

Recollection of places plays no part here. Yesterday, for instance, the
female was installed in a certain room. The feathered males came
fluttering thither for a couple of hours; several even spent the night
there. Next day, at sunset, when I move the cage, all are out of doors.
Ephemeral though they be, the newest comers are ready to repeat their
nocturnal expeditions a second time and a third. Where will they go
first, these veterans of a day?

They know all about the meeting-place of yesterday. One is inclined to
think that they will go back to it, guided by memory, and that, finding
nothing left, they will proceed elsewhither to continue their
investigations. But no: contrary to my expectations, they do nothing of
the sort. Not one reappears in the place which was so thickly crowded
last night; not one pays even a short visit. The room is recognized as
deserted, without the preliminary enquiry which recollection would seem
to demand. A more positive guide than memory summons them elsewhere.

Until now the female has been left exposed, under the meshes of a wire
gauze. The visitors, whose eyes are used to piercing the blackest
gloom, can see her by the vague light of what to us is darkness. What
will happen if I imprison her under an opaque cover? According to its
nature, will not this cover either set free or arrest the tell-tale
effluvia?

Physical science is to-day preparing to give us wireless telegraphy, by
means of the Hertzian waves. Can the Great Peacock have anticipated our
efforts in this direction? In order to set the surrounding air in
motion and to inform pretenders miles away, can the newly-hatched bride
have at her disposal electric or magnetic waves, which one sort of
screen would arrest and another let through? In a word, does she, in
her own manner, employ a kind of wireless telegraphy? I see nothing
impossible in this: insects are accustomed to invent things quite as
wonderful.

I therefore lodge the female in boxes of various characters. Some are
made of tin, some of cardboard, some of wood. All are hermetically
closed, are even sealed with stout putty. I also use a glass bell-jar
standing on the insulating support of a pane of glass.

Well, under these conditions of strict closing, never a male arrives,
not one, however favourable the mildness and quiet of the evening. No
matter its nature, whether of metal or glass, of wood or cardboard, the
closed receptacle forms an insuperable obstacle to the effluvia that
betray the captive’s whereabouts.

A layer of cotton two fingers thick gives the same result. I place the
female in a large jar, tying a sheet of wadding over the mouth by way
of a lid. This is enough to keep the neighbourhood in ignorance of the
secrets of my laboratory. No male puts in an appearance.

On the other hand, make use of ill-closed, cracked boxes, or even hide
them in a drawer, in a cupboard; and, notwithstanding this added
mystery, the Moths will arrive in numbers as great as when they come
thronging to the trellised cage standing in full view on a table. I
have retained a vivid recollection of an evening when the recluse was
waiting in a hat-box at the bottom of a closed wall-cupboard. The Moths
arrived, went to the door, struck it with their wings, knocked at it to
express their wish to enter. Passing wayfarers, coming no one knows
whence across the fields, they well knew what was inside there, behind
those boards.

We must therefore reject the idea of any means of information similar
to that of wireless telegraphy, for the first screen set up, whether a
good conductor or a bad, stops the female’s signals completely. To give
these a free passage and carry them to a distance, one condition is
indispensable: the receptacle in which the female is contained must be
imperfectly closed, so as to establish a communication between the
inner and the outer air. This brings us back to the probability of an
odour, though that was contradicted by my experiment with naphthaline.

My stock of cocoons is exhausted and the problem is still obscure.
Shall I try again another year, the fourth? I abandon the thought for
the fallowing reasons: Moths that mate at night are difficult to
observe if I want to watch their intimate actions. The gallant
certainly needs no illuminant to attain his ends; but my feeble human
powers of vision cannot dispense with one at night. I must have at
least a candle, which is often extinguished by the whirling swarm. A
lantern saves us from these sudden eclipses; but its dim light,
streaked with broad shadows, does not suit a conscientious observer
like myself, who wants to see and to see clearly.

Nor is this all. The light of a lamp diverts the Moths from their
object, distracts them from their business and, if persistent, gravely
compromises the success of the evening. The visitors no sooner enter
the room than they make a wild rush for the flame, singe their fluff in
it and thenceforth, frightened by the scorching received, cease to be
trustworthy witnesses. When they are not burnt, when they are kept at a
distance by a glass chimney, they perch as close as they can to the
light and there stay, hypnotized.

One evening, the female was in the dining-room, on a table facing the
open window. A lighted paraffin-lamp, with a large white-enamel shade,
was hanging from the ceiling. Two of the arrivals alighted on the dome
of the cage and fussed around the prisoner; seven others, after
greeting her as they passed, made for the lamp, circled about it a
little and then, fascinated by the radiant glory of the opal cone,
perched on it, motionless, under the shade. Already the children’s
hands were raised to seize them.

“Don’t,” I said. “Leave them alone. Let us be hospitable and not
disturb these pilgrims to the tabernacle of light.”

All that evening, not one of the seven budged. Next morning, they were
still there. The intoxication of light had made them forget the
intoxication of love.

With creatures so madly enamoured of the radiant flame, precise and
prolonged experiment becomes unfeasible the moment the observer
requires an artificial illuminant. I give up the Great Peacock and his
nocturnal nuptials. I want a Moth with different habits, equally
skilled in keeping conjugal appointments, but performing in the
day-time.

Before continuing with a subject that fulfils these conditions, let us
drop chronological order for a moment and say a few words about a
late-comer who arrived after I had completed my enquiries, I mean the
Lesser Peacock (Attacus pavonia minor, Lin.). Somebody brought me, I
don’t know where from, a magnificent cocoon loosely wrapped in an ample
white-silk envelope. Out of this covering, with its thick, irregular
folds, it was easy to extract a case similar in shape to the Great
Peacock’s, but a good deal smaller. The fore-end, worked into the
fashion of an eel-trap by means of free and converging fibres, which
prevent access to the dwelling while permitting egress without a breach
of the walls, indicated a kinswoman of the big nocturnal Moth; the silk
bore the spinner’s mark.

And, in point of fact, towards the end of March, on the morning of Palm
Sunday, the cocoon with the eel-trap formation provides me with a
female of the Lesser Peacock, whom I at once seclude under a wire-gauze
bell in my study. I open the window to allow the event to be made known
all over the district; I want the visitors, if any come, to find free
entrance. The captive grips the wires and does not move for a week.

A gorgeous creature is my prisoner, in her brown velvet streaked with
wavy lines. She has white fur around her neck; a speck of carmine at
the tip of the upper wings; and four large, eye-shaped spots, in which
black, white, red and yellow-ochre are grouped in concentric crescents.
The dress is very like that of the Great Peacock, but less dark in
colouring. I have seen this Moth, so remarkable for size and costume,
three or four times in my life. It was only the other day that I first
saw the cocoon. The male I have never seen. I only know that, according
to the books, he is half the size of the female and of a brighter and
more florid colour, with orange-yellow on the lower wings.

Will he come, the unknown spark, the plume-wearer on whom I have never
set eyes, so rare does he appear to be in my part of the country? In
his distant hedges will he receive news of the bride that awaits him on
my study table? I venture to feel sure of it; and I am right. Here he
comes, even sooner than I expected.

On the stroke of noon, as we were sitting down to table, little Paul
who is late owing to his eager interest in what is likely to happen,
suddenly runs up to us, his cheeks aglow. In his fingers flutters a
pretty Moth, a Moth caught that moment hovering in front of my study.
Paul shows me his prize; his eyes ask an unspoken question.

“Hullo!” I say. “This is the very pilgrim we were expecting. Let’s fold
up our napkins and go and see what’s happening. We can dine later.”

Dinner is forgotten in the presence of the wonders that are taking
place. With inconceivable punctuality, the plume-wearers hasten to
answer the captive’s magic call. They arrive one by one, with a
tortuous flight. All of them come from the north. This detail has its
significance. As a matter of fact, during the past week we have
experienced a fierce return of winter. The north wind has been blowing
a gale, killing the imprudent almond-blossoms. It was one of those
ferocious storms which, as a rule, usher in the spring in our part of
the world. To-day the temperature has suddenly grown milder, but the
wind is still blowing from the north.

Now at this first visit all the Moths hurrying to the prisoner enter
the enclosure from the north; they follow the movement of the air; not
one beats against it. If their compass were a sense of smell similar to
our own, if they were guided by odoriferous particles dissolved in the
air, they ought to arrive from the opposite direction. If they came
from the south, we might believe them to be informed by effluvia
carried by the wind; coming as they do from the north, through the
mistral, that mighty sweeper of the atmosphere, how can we suppose them
to have perceived, at a great distance, what we call a smell? This
reflux of scented atoms in a direction contrary to the aerial current
seems to me inadmissible.

For a couple of hours, in radiant sunshine, the visitors come and go
outside the front of the study. Most of them search for a long while,
exploring the wall, flitting along the ground. To see their hesitation,
one would think that they were at a loss to discover the exact place of
the bait that attracts them. Though they have come from very far
without mistake, they seem uncertain of their bearings once they are on
the spot. Nevertheless, sooner or later they enter the room and pay
their respects to the captive, without much importunity. At two o’clock
all is over. Ten Moths have been here.

All through the week, each time at noon-day, when the light is at its
brightest, Moths arrive, but in decreasing numbers. The total is nearly
forty. I see no reason to repeat experiments which could add nothing to
what I already know; and I confine myself to stating two facts. In the
first place, the Lesser Peacock is a day insect, that is to say, he
celebrates his wedding in the brilliant light of the middle of the day.
He needs radiant sunshine. The Great Peacock, on the contrary, whom he
so closely resembles in his adult form and in the work which he does as
a caterpillar, requires the dusk of the early hours of the night. Let
him who can explain this strange contrast of habits.

In the second place, a powerful air-current, sweeping the other way any
particles capable of instructing the sense of smell, does not prevent
the Moths’ arriving from a direction opposite to that of the
odoriferous flux, as our physics imagine it.

If I am to go on with my observations, I want a day Moth; not the
Lesser Peacock, who made his appearance too late, at a time when I had
nothing to ask him, but another, no matter whom, provided that he be
quick at discovering nuptial feasts. Shall I find this Moth?



CHAPTER XII

THE BANDED MONK


Yes, I shall find him; indeed I have him already. A little chap of
seven, with a wideawake face that doesn’t get washed every day, bare
feet and a pair of tattered breeches held up by a bit of string, a boy
who comes regularly to supply the house with turnips and tomatoes,
arrives one morning carrying his basket of vegetables. After the few
sous due to his mother for the greens have been counted one by one into
his hand, he produces from his pocket something which he found the day
before, beside a hedge, while picking grass for the Rabbits:

“And what about this?” he asks, holding the thing out to me. “What
about this? Will you have it?”

“Yes, certainly I’ll have it. Try and find me some more, as many as you
can, and I’ll promise you plenty of rides on the roundabout on Sunday.
Meanwhile, my lad, here’s a penny for you. Don’t make a mistake when
you give in your accounts; put it somewhere where you won’t mix it up
with the turnip-money.”

Dazzled with delight at the sight of so much wealth, my little
ragamuffin promises to search with a will, already seeing visions of a
fortune to be his.

When he has gone, I examine the thing. It is worth while. It is a
handsome cocoon, blunt-shaped, not at all unlike the product of our
Silk-worm nurseries, of a firm consistency and a tawny colour. The
cursory information which I have picked up from books of reference
makes me almost certain that it is the Bombyx of the Oak, the Oak
Eggar. If this is so, what luck! I shall be able to continue my
observations and perhaps complete what the Great Peacock began to show
me.

The Oak Eggar is, in fact, a classic; there is not an entomological
treatise but speaks of his exploits in the wedding-season. They tell us
how a mother hatches in captivity, inside a room and even hidden in a
box. She is far away from the country, amid the tumult of a big town.
The event is nevertheless divulged to those whom it concerns in the
woods and the meadows. Guided by some inconceivable compass, the males
arrive, hastening from the distant fields; they go to the box, tap at
it, fly round and round it.

I had read of these marvels; but seeing, seeing with one’s own eyes,
and at the same time experimenting a little is quite another matter.
What does my penny purchase hold in store for me? Will the famous
Bombyx emerge from it?

Let us call her by her other name: the Banded Monk. This unusual name
of Monk is suggested by the male’s dress: a monk’s frock of a modest
rusty brown. But in this case the stuff is a delicious velvet, with a
pale transversal band and a little white, eye-shaped dot on the front
wings.

The Banded Monk is not, in my region, a common Moth whom we are likely
to catch if the fancy takes us to go out with a net at the proper
season. I have never seen it about the village, especially not in my
lonely enclosure, during all the twenty years that I have spent here. I
am not a fervent hunter, I admit; the collector’s dead insect interests
me very little; I want it alive, in the full exercise of its faculties.
But I make up for the absence of the collector’s zeal by an attentive
eye for all that enlivens the fields. A Moth so remarkable in size and
costume would certainly not have escaped me had I met him.

The little seeker whom I had caught so nicely with a promise of the
roundabout never made a second find. For three years I requisitioned
friends and neighbours, especially the youngsters, those sharp-eyed
scrapers of the brushwood; I myself scraped a great deal under masses
of dead leaves, inspected stone-heaps, examined hollow tree-trunks. My
trouble was in vain: the precious cocoon was nowhere to be found.
Suffice it to say that the Banded Monk is very scarce in my
neighbourhood. The importance of this detail will be seen when the time
comes.

As I suspected, my solitary cocoon did belong to the famous Moth. On
the 20th of August there emerges a female, corpulent and big-bellied,
attired like the male, but in a lighter frock, more in the nankeen
style. I establish her in a wire-gauze bell-jar in the middle of my
study, on the big laboratory-table, littered with books, pots, trays,
boxes, test-tubes and other engines of science. I have described the
setting before: it is the same as in the case of the Great Peacock. The
room is lighted by two windows looking out on the garden. One is
closed, the other is kept open day and night. The Moth is placed
between the two, in the shadow, some four or five yards away.

The rest of the day and the following day pass without anything worth
mentioning. Hanging by her claws to the front of the trellis-work, on
the side nearest the light, the prisoner is motionless, inert. There is
no waving of the wings, no quivering of the antennæ. Even so did the
female Great Peacock behave.

The mother Bombyx matures; her tender flesh hardens. By some process of
which our science has not the remotest idea, she elaborates an
irresistible bait which will bring callers flocking to her from the
four corners of the heavens. What takes place in that fat body, what
transformations are performed that shall presently revolutionize
everything around? Were they known to us, the Moth’s nostrums would add
a cubit to our stature.

On the third day the bride is ready. The festivities burst into full
swing. I was in the garden, already despairing of success, so long were
things delayed, when, at about three o’clock in the afternoon, in very
hot weather and brilliant sunshine, I saw a host of Moths gyrating in
the embrasure of the open window.

It is the lovers coming to call upon their sweetheart. Some are just
leaving the room, others going in, others again are perched upon the
wall, resting as though jaded after a long journey. I see some
approaching in the distance, over the walls, over the curtain of
cypress-trees. They are hurrying up from all directions, but becoming
more and more rare. I missed the beginning of the reception; and the
guests are nearly all here.

Let us go upstairs. This time, in broad daylight, without losing a
single detail, I once more witness the bewildering spectacle into which
the great night Moth initiated me. My study is filled with a swarm of
males, whom I estimate at a glance to number about sixty, as far as it
is possible to make a count in this seething mass. After circling a few
times round the cage, several go to the open window, but return again
forthwith and resume their evolutions. The most eager perch on the
cage, hustle and trample on one another, fighting for the good places.
Inside the barrier, the captive waits impassively, with her great
paunch hanging against the wires. She gives not a sign of emotion in
the presence of the turbulent throng.

Going in or going out, fussing round the cage or flitting through the
room, for more than three hours they keep up their frenzied saraband.
But the sun is sinking, the temperature becomes a little cooler.
Chilled likewise is the ardour of the Moths. Many go out and do not
come in again. Others take up their positions in readiness for the
morrow; they settle on the transoms of the closed window, as the Great
Peacocks did. The celebration is over for to-day. It will certainly be
renewed to-morrow, for it is still without result, because of the
wires.

But alas, to my great dismay, it is not renewed; and this through my
own fault! Late in the day, some one brings me a Praying Mantis, worthy
of attention because of her exceptionally small size. Preoccupied with
the events of the afternoon, without thinking what I am doing, I
hastily place the carnivorous insect in the cage that holds my Bombyx.
Not for a moment do I dream that this co-habitation can turn out ill.
The Mantis is such a little, slender thing; the other is so obese! And
thus I entertained no apprehensions.

Ah, little did I know the bloodthirsty fury of which the grapnelled
insect is capable! Next morning, to my bitter astonishment, I find the
tiny Mantis devouring the huge Moth. The head and the front part of the
breast have already disappeared. Horrible creature! What a
disappointment I owe to you! Farewell to my researches, which I had
cherished in my imagination all night long; not for three years shall I
be able to resume them, for lack of a subject.

Bad luck must not, however, make us forget the little that we have
learnt. At one sitting, some sixty males came. Considering the rarity
of the Monk and remembering the years of fruitless searches conducted
by my assistants and myself, we stand astounded at this number. With a
female for a bait, the undiscoverable has suddenly become a multitude.

Now where did they come from? From every quarter and from very far,
beyond a doubt. During my years of exploration of my neighbourhood, I
have got to know every bush in it and every heap of stones; and I am in
a position to declare that there are no Oak Eggars there. To make the
swarm that filled my study, the whole of the surrounding district must
have contributed, from this side and from that, within a radius which I
dare not determine.

Three years pass; and fortune persistently entreated at last grants me
two Monk-cocoons. Towards the middle of August, both of them, within a
few days of each other, give me a female. This is a piece of luck which
will allow me to vary and renew my tests.

I quickly repeat the experiments which have already procured me a most
positive reply from the Great Peacock. The pilgrim of the day is no
less clever than the pilgrim of the night. He baffles all my tricks. He
hastens infallibly to the prisoner, in her wire-gauze cage, in whatever
part of the house the apparatus be installed; he is able to discover
her hidden in a cupboard; he guesses her secret presence in a box of
any kind, provided that it be not tightly closed. He ceases to come,
for lack of information, when the casket is hermetically sealed. Thus
far we see merely a repetition of the feats of the Great Peacock.

A well-closed box, the air contained in which does not communicate with
the outer atmosphere, leaves the Monk in complete ignorance of the
prisoner’s whereabouts. Not one arrives, even when the box is exposed
for every eye to see in the window. This brings back, more urgently
than ever, the idea of odoriferous effluvia, intransmissible through a
wall of metal, cardboard, wood or glass, no matter which.

When put to the test, the great night Moth was not baffled by the
naphthaline, whose powerful smell ought, to my thinking, to mask
ultrasubtle emanations, imperceptible to any human nostrils. I repeat
the experiment with the Monk. This time I lavish all the resources in
the way of scents and stenches that my store of drugs permits.

I place the saucers, partly inside the wire-gauze cage, the female’s
prison, and partly all round it, in a continuous circle. Some contain
naphthaline, others oil of lavender, others paraffin, others, lastly,
alkaline sulphurs smelling of rotten eggs. Short of asphyxiating the
prisoner, I can do no more. These arrangements are made in the morning,
so that the room may be thoroughly saturated when the trysting-hour
arrives.

In the afternoon, the study has become an odious laboratory in which
the penetrating aroma of lavender-oil and the foul stench of
sulphuretted hydrogen predominate. Remember that I smoke in this room
and plentifully at that. Will the concentrated odours of a gas-works, a
smoker’s divan, a scent-shop, an oil-well and a chemical factory
succeed in putting off the Monk?

Not at all. A little before three, the Moths arrive, as numerous as
ever. They go to the cage, which I have taken pains to cover with a
thick kitchen-cloth, so as to increase the difficulty. Though they see
nothing after they have entered, though they are steeped in a foreign
atmosphere in which any subtle fragrance should have been annihilated,
they fly towards the prisoner and try to get at her by slipping under
the folds of the cloth. My artifices are fruitless.

After this reverse, so definite in its results, which repeats what my
naphthaline experiment with the Great Peacock taught me, I ought,
logically speaking, to give up the theory that odorous effluvia serve
as a guide to the Moths invited to the nuptial feast. That I did not do
so was due to a casual observation. The unexpected, the fortuitous,
often provides us with one of those surprises which show us the road to
the truth, hitherto sought in vain.

One afternoon, trying to discover whether sight plays any part in the
search, once that the Moths have entered the room, I place the female
in a glass bell-jar and give her a little oak-branch, with withered
leaves, as a perch. The apparatus is put on a table, opposite the open
window. On entering, the Moths cannot fail to see the prisoner,
standing as she does where they are bound to pass. The pan with its
layer of sand, in which the female spent the previous night and the
morning under a wire-gauze cover, is in my way. I put it, without
premeditation, on the floor at the other end of the room, in a corner
which is only dimly lighted. It is seven yards from the window.

The result of these preparations upsets all my ideas. Of the Moths
arriving, none stops at the glass bell, where the female is plainly
visible, in the full light. They pass by with utter indifference. Not a
glance in her direction, not an enquiry. They all fly right to the far
end of the room, to the dusky corner where I placed the tray and the
cage. They alight on the trellised top and explore it at length,
flapping their wings and hustling one another a little. All the
afternoon, until sunset, they dance around the deserted dome the same
saraband to which the actual presence of the female would give rise. At
last they fly away, but not all of them. There are persistent ones who
refuse to go, rooted to the spot by some magic attraction.

A strange result indeed: my Moths hasten to where there is nothing,
take their stand there and will not be dissuaded by the repeated
warnings of their eyes; they pass without stopping for a moment by the
bell-glass in which the female cannot fail to be perceived by one or
other of those coming and going. Befooled by a lure, they pay no
attention to the real thing.

What is it that deceives them? The whole of the night before and all
this morning, the female has sojourned under the wire-gauze cover,
either hanging to the trellis-work, or resting on the sand in the pan.
Whatever she touched, above all with her fat belly apparently, has
become impregnated, as the result of long contact, with certain
emanations. There you have her bait, her love-philtre; there you have
what revolutionizes the world of Monks. The sand retains it for a time
and spreads its effluvia around.

It is smell therefore that guides the Moths, that gives them
information at a distance. Dominated by the sense of smell, they take
no notice of what their eyes tell them; they pass by the glass prison
in which their lady-love is now interned; they go to the wires, to the
sand, on which the magic cruets have shed their contents; they race to
the wilderness where naught remains of the witch but the scented
evidence of her sojourn.

The irresistible philtre takes a certain time to elaborate. I picture
it as an exhalation which is gradually given off and saturates
everything that touches the fat, motionless creature. When the glass
bell stands directly on the table or, better still, on a square of
glass, the communication between the interior and the outer air is
insufficient; and the males, perceiving nothing by the sense of smell,
keep away, however long the experiment be continued. At the actual
moment, I cannot substantiate this non-transmission through a screen,
for, even if I establish ample communication, if I separate the bell
from its support by means of three wedges, the Moths do not come at
first, however many there may be in the room. But wait for half an
hour, more or less: the alembic of feminine flavours begins its
distilling and the rush of visitors takes place as usual.

Now that I possess these data, this unexpected light on the subject, I
am at liberty to vary my experiments, all of which lead to the same
conclusion. In the morning, I establish the female under a wire-gauze
cover. Her perch is a little oak-twig similar to the last. Here,
motionless, as though dead, she remains for long hours, buried in the
tuft of leaves that is to be impregnated with her emanations. When
visiting-time approaches, I withdraw the twig, perfectly saturated, and
lay it on a chair, near the open window. On the other hand, I leave the
female under her cover, well in view on the table, in the middle of the
room.

The Moths arrive, first one, then two and three, soon five and six.
They come in, go out, come in again, fly up and down, go to and fro,
keeping all the time to the neighbourhood of the chair with its
oak-branch. Not one makes for the big table, a few paces farther into
the room, where the female is waiting for them under the trellised
dome. They are hesitating, that is clear; they are seeking.

At last they find. And what do they find? The very twig which in the
morning had served the pot-bellied matron as a bed. With wings swiftly
fluttering, they alight upon the branch; they explore it above and
below, probe it, lift it and move it, until at last the little bit of
foliage drops on the floor. The probing between the leaves continues
none the less. Under the buffeting of the wings and the clawing of the
feet, the stick is now running along the ground, like a scrap of paper
pawed by a kitten.

While the twig is moving away with its band of explorers, two new
arrivals come upon the scene. On their way, they have to pass the
chair, which for a brief spell bore the leafy stick. They stop at it
and eagerly investigate the very spot which but now was covered by the
branch. And yet, in their case as in that of the others, the real
object of their desires is close by them, under a wire gauze which I
have omitted to veil. No one notices it. On the floor, the Monks
continue to hustle the mattress on which the female lay in the morning;
on the chair, they still fumble at the spot where this bedding was
first placed. The sun goes down; the time comes to depart. Besides, the
effluvia of passion are growing fainter, are dispersing. The visitors
go away without more ado. Good-bye till to-morrow.

The following tests tell me that any material, no matter what, can take
the place of the leafy branch, that chance inspiration of mine. Some
time in advance, I place the female on a couch of cloth or flannel, of
wadding or paper. I even subject her to the hardship of a camp-bed of
wood, glass, marble or metal. All these objects, after a contact of
sufficient length, have the same powerful attraction for the males as
the mother Monk herself. They retain this property to a varying extent,
according to their nature. The best are wadding, flannel, dust, sand,
in short, porous objects. Metals, marble and glass, on the contrary,
soon lose their efficacy. Lastly, anything on which the female has
rested communicates its virtue to other places by simple contact, as
witness the Moths crowding to the seat of the cane-bottomed chair after
the oak-branch had fallen from it.

Let us use one of the best beds, flannel, for instance, and we shall
see a curious thing. I place at the bottom of a long test-tube or of a
narrow-necked bottle, just wide enough to allow of the Moth’s passage,
a piece of flannel on which the mother has been lying all the morning.
The callers go into the vessels, flounder about, do not know how to get
out again. I have invented a mouse-trap for them by means of which I
could do terrific execution. Let us release the poor things, remove the
piece of stuff and put it away in an hermetically closed box. The
infatuated Moths go back to the test-tube, headlong reenter the trap.
They are attracted by the effluvia which the saturated flannel has
imparted to the glass.

I am fully convinced. To summon the Moths of the district to the
wedding, to apprise them at a distance of her presence and to guide
them, the bride emits an extremely subtle scent, imperceptible to our
own organs of smell. With the mother Monk held to their nostrils, those
around me perceive not the least odour, not even the youngest, whose
senses are not yet vitiated.

This quintessence easily impregnates every object on which the female
rests for any length of time; and thenceforth the actual object becomes
as potent a centre of attraction as the mother herself, until the
emanations are dispelled.

Nothing visible betrays the bait. On a piece of paper, a recent
resting-place around which the visitors crowd, there is not an
appreciable trace, no moisture of any kind; the surface is just as
clean as before the impregnation.

The product is slowly elaborated and has to accumulate a little while
before manifesting its full strength. When taken from her couch and
placed elsewhere, the female loses her attractions for the time and
becomes an object of indifference; it is the resting-place, saturated
by long contact, that draws the newcomers. But the batteries are
recharged and the deserted one recovers her power.

The appearance of the warning effluvium is delayed for a longer or
shorter period according to the species. The newly-hatched Moth has to
mature for a time and to put her distillery in order. A female Great
Peacock, born in the morning, sometimes has visitors that same evening,
but oftener on the second day, after preparations lasting some forty
hours. The female Banded Monk adjourns her summons longer than that:
her banns of marriage are not published until after two or three days’
waiting.

Let us return for a moment to the problematical functions of the
antennæ. The male Monk sports a sumptuous pair, similar to those of the
Great Peacock, who vies with him in his matrimonial expeditions. Are we
to look upon these hairy feelers as a guiding compass? I repeat,
without laying much stress on the matter, my former amputations. None
of the patients comes back. We must be chary of drawing inferences,
however. The Great Peacock has shown us that the failure to return is
due to more serious reasons than amputation of the horns.

Moreover, a second Monk, the Clover Bombyx, nearly akin to the first
and, like him, superbly plumed, sets us an exceedingly perplexing
problem. He is fairly plentiful around my place; even in the enclosure
I find his cocoon, which might easily be confused with that of the Oak
Bombyx. I am deceived at first by the resemblance. Out of six cocoons,
from which I expected to obtain Banded Monks, six females of the other
species hatch at the end of August. Well, around those six females,
born in my house, never a male appears, though there is no doubt that
the tufted ones are present in the neighbourhood.

If spreading feathered antennæ are really organs for receiving
information at a distance, why are not my richly-horned neighbours
informed of what is happening in my study? Why do their fine plumes
leave them indifferent to events that would bring the Banded Monk
hastening up in crowds? Once more, the organ does not determine the
aptitude. This one is gifted and that one is not, despite organic
similarity.



CHAPTER XIII

THE SENSE OF SMELL


In physics we hear of nothing nowadays but the Röntgen rays, which
penetrate dense bodies and photograph the invisible for us. A fine
discovery, but how insignificant in face of the surprises which the
future reserves for us when, better-informed of the why and wherefore
of things, we supplement with art the feebleness of our senses and
succeed in rivalling, be it ever so little, the keenness of perception
revealed by the brute creation.

How enviable, in many cases, is this animal superiority! It teaches us
the poverty of our attainments; it declares the mediocrity of our
sensory apparatus; it gives us evidence of impressions foreign to our
nature; it proclaims realities so far in excess of our attributes that
they astound us.

A wretched caterpillar, the Pine Processionary, splits his back into
meteorological air-holes which snuff the coming weather and foretell
the squall; the bird of prey, with its incomparably long sight, sees
from high in the clouds the Field-mouse squatting on the ground; the
blinded Bats guide their flight without injury to themselves amid
Spallanzani’s [32] inextricable maze of threads; the Carrier-pigeon,
though moved a hundred leagues from home, infallibly regains his cote
across immensities which he has never traversed unaided; within the
limits of her humbler flight, a Bee, the Chalicodoma, [33] also spans
the unknown, accomplishes a long journey and returns to her mass of
cells.

The man who has never seen a Dog hunting for truffles does not know one
of the finest achievements of the sense of smell. Absorbed in its
functions, the animal trots along, with its nose to the wind, at a
moderate pace. It stops, questions the ground with its nostrils,
scratches for a few seconds, without undue excitement, and looks up at
its master:

“Here we are,” it seems to say, “here we are! On my word of honour as a
Dog, there’s a truffle here.”

And it speaks the truth. The master digs at the point indicated. If the
trowel goes astray, the Dog shows the man how to put it right by
sniffing at the bottom of the hole. Do not be afraid of the stones and
roots in between: despite the depth and intervening obstacles, the
tuber will come. A Dog’s nose cannot lie.

“Subtlety of smell,” you say.

I have no objection, if by that you mean that the animal’s nasal
passages are the organ of perception; but is the thing perceived always
a mere smell, in the ordinary acceptation of the word, an effluvium
such as our own senses understand it? I have some reason to doubt this.
Let us set the matter forth.

I have had the good fortune on several occasions to accompany a Dog who
was a great expert at his trade. Certainly he was nothing to look at,
this artist whom I was so anxious to see at work: just a Dog, placid
and deliberate in his ways, ugly, unkempt; the sort of Dog that you
would never admit to your fireside. Talent and poverty often go hand in
hand.

His master, a celebrated rabassier [34] in the village, convinced that
I had no intention of stealing his secrets and one day setting up in
competition, allowed me to join him in his expeditions, a favour which
he did not often grant. The worthy man was quite willing to fall in
with my views, once he saw that I was not an apprentice but merely an
enquirer who made drawings [35] and wrote down lists of underground
vegetable things, instead of marketing my bagful of treasure-trove, the
glory of the Christmas Turkey.

It was agreed between us that the Dog should act as he pleased and
receive a bit of bread as his reward after each discovery,
indiscriminately. Every spot scratched up by his paws was to be dug and
the object indicated extracted without our troubling about its
commercial value. In no case was the master’s experience to intervene
and divert the dog from a spot where practice told him that nothing
saleable was to be found, for, in drawing up my botanical lists, I
preferred wretched and unmarketable products to the choicest morsels,
though these of course were welcomed when they appeared.

Thus conducted, the underground botanizing was very fruitful. With his
perspicacious nose, the Dog made me gather indifferently the large and
the small, the fresh and the putrid, the scented and the unscented, the
fragrant and the stinking. I was amazed at my collection, which
comprised the greater part of the hypogean fungi in my neighbourhood.

What a variety of structure and above all of odour, the primary quality
in this question of scent! There are some that have nothing more
noticeable than a vague fungous mustiness, which is more or less
evident in all. Some smell of turnips, of rotten cabbage; some are
fetid enough to fill the collector’s house with their stench. The real
truffle alone possesses the aroma dear to the epicure.

If smell, as we understand it, is the Dog’s only guide, how does he
manage to find his way through all these incongruous odours? Is he
apprised of the contents of the soil by a general emanation, the
fungous effluvium common to the different species? In that case an
extremely embarrassing question arises.

I paid some attention to the ordinary mushrooms, many of which, as yet
invisible, announced their coming as imminent by cracking the surface
of the ground. Now I never saw the Dog stop at any of those points
where my eyes divined the cryptogam pushing back the earth with the
thrust of its cap, points where the ordinary fungous smell was
certainly most pronounced. He passed them by scornfully, with not a
sniff, with not a stroke of his paw. And yet the thing was underground;
and its reek was similar to others which he sometimes pointed out to
us.

I came back from the Dog’s school with the conviction that the
truffle-detecting nose has a better guide than smell, in the sense in
which our olfactory powers realize it. It must perceive, in addition,
effluvia of a different order, full of mystery to us, who are not
equipped accordingly. Light has its dark rays, which are without effect
upon our retinæ, but not apparently upon all. Why should not the domain
of smell have its secret emanations, unknown to our senses but
perceptible to a differently constructed organ of smell?

If the scent of the Dog leaves us perplexed to this extent, that it is
impossible for us to say exactly or even to suspect what it perceives,
it at least tells us plainly that we should be greatly mistaken to
compare everything by human standards. The world of sensations is far
larger than the limits of our sensibility admit. What a number of facts
in the working of the forces of nature escape us for want of organs
delicate enough to perceive them!

The unknown, that inexhaustible field which the future will cultivate,
holds harvests in store for us beside which our present knowledge is
but a pitiful gleaning. Under the sickle of science sheaves will one
day fall whose grain to-day would seem a senseless paradox. Scientific
illusions? Not so, if you please, but undeniable and positive
realities, affirmed by the animal world, which in certain respects has
a great advantage over the world of man.

In spite of his long professional practice, in spite of the aroma of
the tuber which he is seeking, the rabassier cannot guess the presence
of the truffle, which ripens in winter underground, at a depth of
eighteen inches or so; he needs the aid of the Dog or the Pig, whose
scent pries into the secrets of the soil. Well, these secrets are known
to different insects even better than to our two helpers. In order to
discover the tuber on which their family of grubs is to be fed, they
possess a scent of exceptional perfection.

Long ago, from truffles dug up spoilt and teeming with vermin and
placed in this condition in a glass jar with a layer of fresh sand, I
obtained first a small red Beetle (Anisotoma cinnamomea, Panz.) and
then various Diptera, including a Sapromyzon, who, with her sluggish
flight and feeble frame, reminds me of a Fly, clad in yellow velvet,
known as Scatophaga scybalaria, that placid frequenter of human
excrement in autumn.

The latter finds her truffle on the surface of the ground, at the foot
of a wall or hedge, man’s usual hasty refuge in the country; but how
does the other know at what point underground lies hers, or rather her
grubs’ truffle? To go down and hunt about in the depths is beyond her
power. Her frail limbs, which the moving of a grain of sand would warp;
her wings, which, if extended, would block her way through a gorge; her
dress of stiff silk, militating against a smooth passage: these are all
against her. The Sapromyzon is obliged to lay her eggs on the surface
of the soil, but she must do so at the very spot beneath which the
truffle lies, for the tiny grubs would die if they had to roam at
random until they came upon their provender, which is always sparsely
distributed.

The truffle-hunting Fly is therefore informed by her sense of smell of
the spots favourable to her maternal plans; she possesses the scent of
the rabassier Dog, indeed probably a better one, for she knows things
by nature, having never been taught, whereas her rival has only
received an artificial education.

It would be interesting to follow the Sapromyzon’s manœuvres, but the
idea strikes me as impracticable. The insect is rare, flies away
quickly and is soon out of sight. To observe it closely, to watch it at
work would involve a great loss of time and a degree of assiduity of
which I do not feel capable. Another discoverer of underground fungi
shall reveal what the Fly could hardly be expected to show us.

This is a pretty little black Beetle, with a pale and velvety belly,
round as a cherry-stone and much the same size. The insect’s official
title is Bolboceras gallicus, Muls. By rubbing the tip of its abdomen
against the edge of its wing-cases it emits a soft chirrup similar to
that of the little birds when their mother comes home with their food.
The male wears a graceful horn on his head, copied on a smaller scale
from that of the Spanish Copris. [36]

Deceived by this armour, I at first took the insect for a member of the
Dung-beetles’ corporation and brought it up as such in captivity. I
served it with these stercoral dainties which are most appreciated by
its presumed colleagues. But never, no, never did it consent to touch
them. Fie, for shame! Dung to a Bolboceras! Well! What on earth did I
take him for? The epicure expects something very different. He wants
not exactly the truffle of our banquets, but its equivalent.

This characteristic was not displayed to me without patient
investigation on my part. At the southern foot of the Sérignan hills,
not far from the village, stands a thicket of maritime pines,
alternating with rows of cypress-trees. Here, at the season of All
Saints, after the autumnal rains, the mushrooms abound that frequent
the Coniferæ, in particular the delicious milk-mushroom, which turns
green at any part that is bruised and sheds tears of blood when you
break it. [37] In the mild days of autumn this is the favourite walk of
my household, being far enough to exercise young legs and near enough
not to tire them.

They find everything there: old Magpies’ nests, formed of bundles of
twigs; Jays squabbling with one another, after filling their crops with
acorns on the oaks hard by; Rabbits suddenly starting out of a
rosemary-bush, showing their little white upturned scuts; Geotrupes
[38] hoarding away food for the winter and heaping up their rubbish on
the threshold of the burrow. And then lovely sand, soft to the touch,
easy to dig into tunnels, easy to build into rows of huts which we
thatch with moss and surmount with a bit of reed by way of a chimney;
and the delicious lunch off an apple to the sound of the Æolian harps
softly sighing through the pine-needles!

Yes, for the children it is a real paradise, where one goes as a reward
for well-learnt lessons. The grown-ups also have their share of
enjoyment. As far as I am concerned, I have for many years been
watching two insects here, without succeeding in discovering their
family secrets. One of them is Minotaurus typhœus, [39] whose male
carries on his corselet three spikes pointing in front of him. The old
writers used to call him the Phalangist, because of his armour, which
may be compared with the three lines of spears of the Macedonian
phalanx.

He is a robust fellow, who cares nothing for the winter. All through
the cold season, whenever the weather turns a trifle milder, he leaves
his house discreetly, at nightfall, and gathers, in the immediate
neighbourhood of his burrow, a few Sheep-droppings, ancient,
olive-shaped remains dried by the summer sun. He heaps them in a stack
at the bottom of his larder, shuts the door and eats. When the
provisions are all crumbed and drained of their niggardly juices, he
climbs back to the surface and renews his stores. Thus does he spend
the winter, never resting from his work, except when the weather is too
severe.

The second object of my observations in the pine-wood is the
Bolboceras. His burrows, distributed here and there, among those of the
Minotaur, are easily distinguished. The Phalangist’s are surmounted by
a bulky mound the materials of which are heaped into a cylinder as long
as one’s finger. Each of these rolls is a load of rubbish pushed
outside by the digger, thrusting with his back from below. The orifice
moreover is closed whenever the Beetle is at home, either enlarging the
shaft or peacefully enjoying his possessions.

The Bolboceras’ lodging is open and surrounded merely by a padding of
sand. Its depth is slight, nine inches, hardly more. It goes straight
down in very loose soil. It is easily inspected, therefore, if we take
care first to dig a trench in front of it, which will enable us later
to cut away the perpendicular wall, slice by slice, with the blade of a
knife. The burrow then appears at full length, from top to bottom, in a
semicylindrical shape.

Often the violated dwelling-house is empty. The insect has left during
the night, having finished its business there and gone to settle
elsewhere. The Bolboceras is a nomad, a night-walker, who leaves his
home without regret and easily acquires a new one. Sometimes also the
insect is found at the bottom of the pit: at one time a male, at
another a female, but never the two at a time. The sexes, both equally
zealous in digging burrows, work separately, not together. This is not,
in fact, a family residence, containing the nursery of the young; it is
a temporary abode, dug by each occupant for his own comfort.

Sometimes we find nothing there but the well-sinker, surprised during
his work of excavation; sometimes, lastly—and the case is not
uncommon—the hermit of the crypt embraces with his legs a small
hypogean fungus, either intact or partly consumed. He clutches it
convulsively, refuses to be parted from it. It is his booty, his
fortune, his worldly goods. Scattered crumbs tell us that we have
caught him feasting.

Let us take his prize away from him. We shall see a sort of irregular,
rugged purse, closed on every side and varying in size between a pea
and a cherry. Outside it is reddish, rough with little warts; inside it
is smooth and white. The spores, which are ovoid and diaphanous, are
contained, in rows of eight, in long satchels. By these characteristics
we recognize an underground cryptogamous product, nearly related to the
truffles and known to botanists as Hydnocystis arenaria, Tul.

This throws a light upon the habits of the Bolboceras and upon the
reason why his burrows are so frequently renewed. In the calm of the
twilight, the little gadabout takes to the fields, chirruping softly as
he goes, cheering himself with song. He explores the soil, questions it
as to its contents, just as the Dog does when hunting for truffles. His
sense of smell warns him when the coveted morsel is underneath, covered
by a few inches of sand. Certain of the exact spot where the thing
lies, he digs straight down and never fails to reach it. As long as the
provisions last, he does not go out again. Blissfully he feeds at the
bottom of the well, heedless of the door left open or hardly barred.

When no more food remains, he moves, looking for another loaf, which
will become the excuse for a fresh burrow, to be abandoned in its turn.
Each fungus consumed represents a new house, which is a mere refectory,
a traveller’s refreshment-room. Thus are the autumn and spring, the
seasons of the hydnocystis, spent in the pleasures of the table, from
one home to the next.

To study the rabassier insect more closely, in my own house, I should
need a little store of its favourite fare. It would be waste of time to
seek for it myself, by digging at random: the little cryptogam is not
so plentiful that I can hope to strike it with my trowel without a
guide. The truffle-hunter needs his Dog; my informer shall be the
Bolboceras himself. Behold me turned into a rabassier of a new kind. I
reveal my secret, which can only raise a smile from my original
instructor in underground botany, if he should ever hear of my singular
form of competition.

The subterranean fungi occur only at certain points, often in groups.
Now the Beetle has been this way; with his delicate scent he has
recognized the site as good, for the burrows are numerous hereabouts.
We will therefore dig near the holes. The clue is accurate. In a few
hours, thanks to the tracks left by the Bolboceras, I possess a handful
of hydnocystes. It is the first time that I have gathered this
particular fungus. Let us now catch the insect. That presents no
difficulties: we have only to dig up the burrows.

I make my experiments the same evening, filling a large earthen pan
with fresh, sifted sand. With a stick as thick as my finger, I make six
vertical tunnels in the sand, two decimetres [40] deep and placed at a
suitable distance apart. A hydnocystis is lowered to the bottom of
each; and I insert a fine straw, to show me the exact position later.
Lastly, I fill up the six cavities with caked sand. When this surface
has been carefully smoothed, so that the level is everywhere the same,
except for the six straws, landmarks that mean nothing to the
Bolboceras, I let loose my captives, covering them with a wire-gauze
cage. There are eight of them.

At first there is nothing to see save the inevitable uneasiness due to
the incidents of their exhumation, transport and confinement in an
unknown place. My exiles from home try to escape, climb up the wire,
burrow right at the edge of the enclosure. Night falls and things grow
calmer. Two hours later, I come to take a last look at them. Three are
still buried under a thin layer of sand. The five others have each dug
a perpendicular shaft at the very foot of the straws which tell me
where the fungi lie. Next morning, the sixth straw has its well like
the others.

This is the moment to see what is happening underground. I remove the
sand methodically in vertical slices. At the bottom of each burrow is a
Bolboceras eating his truffle, the hydnocystis.

Let us repeat the experiment with the partly-consumed victuals. The
result is the same. At one brief, nocturnal spell of work, the dainty
is discovered underground and reached by means of a gallery which runs
plumb to the spot where the morsel lies. There is no hesitation, no
trial excavation guided by guesswork. This is proved by the surface of
the soil, which everywhere is just as I left it when I smoothed it
down. The insect could not have made straighter for the coveted object
had it been guided by sight; it always digs at the foot of the straws,
my sign-posts. The Dog, nosing the ground for truffles, hardly achieves
this degree of precision.

Has the hydnocystis then a very pungent smell, able to give such
positive information to its consumer’s scent? Not at all. To our
nostrils it is a neutral object, devoid of any appreciable olfactory
character. A tiny pebble taken out of the ground would impress us just
as much with its faint aroma of fresh earth. As a revealer of
underground fungous products, the Bolboceras here rivals the Dog. He
would even rise superior to the Dog, were he able to generalize. But he
is a rigorous specialist: he knows only the hydnocystis. Nothing else,
so far as I am aware, tempts him to dig. [41]

Both of them search the subsoil very closely, at the level of the
ground; and the object which they seek is not far down. Were they
farther away, neither the Dog nor the insect would notice effluvia so
subtle, not even the smell of a truffle. To make an impression at a
great distance, powerful odours are needed, capable of perception by
our olfactory sense. Then the exploiters of the odorous thing come
hastening up on all sides from afar.

When, for the purpose of my studies, I require insects that dissect
corpses, I expose a dead Mole in the sun, in a distant corner of the
enclosure. As soon as the animal swells, distended by the gases of
putrefaction, and the skin begins to turn green and the fur to fall
from it, up come numbers of Silphæ [42] and Dermestes, [43] Necrophori
[44] and other Burying-beetles, of whom one would find not a single
specimen in the garden, or even in the neighbourhood, without this
bait.

They have been informed by their sense of smell, at a great distance
all around, whereas I myself can avoid the stench by taking a few steps
back. Compared with their scent, mine is contemptible; but still, in
their case as well as mine, there is really here what our language
calls a smell.

I can do better still with the flower of the dragon arum (Arum
dracunculus), so remarkable for its shape and for its unequalled
stench. Imagine a wide, lanceolate blade, of a clarety purple, half a
yard long and rolled below into an ovoid pouch the size of a hen’s egg.
Through the opening of this wallet rises a central column springing
from the bottom, a long, bright-green club, encircled at its base by
two bracelets, one of ovaries, the other of stamens. Such, briefly
described, is the flower, or rather the inflorescence, of the dragon
arum.

For two days it exhales a frightful stench of carrion, worse than the
proximity of a dead Dog would yield. During the hottest part of the
day, with a wind blowing, it is loathsome, unbearable. Let us brave the
infected atmosphere and go up to it; we shall behold a curious sight.

Informed by the foul odour, which spreads far and wide, various insects
come flying along, such insects as make sausage-meat of small
corpses—Toads, Adders, Lizards, Hedgehogs, Moles, Field-mice—which the
husbandman hits with his spade and flings away disembowelled on the
foot-path. They swoop down upon the great leaf, which, with its livid
purple, looks like a strip of meat gone bad; they caper about,
intoxicated by the smell of corpse which they love; they roll down the
slope and are swallowed up in the purse. After a few hours of bright
sunshine, the receptacle is full.

Let us look inside, through the narrow opening. No elsewhere could you
see such a crowd. It is a mad whirl of backs and bellies, of wing-cases
and legs, swarming, rolling over and over, amid the snap of interlocked
joints, rising and falling, floating and sinking, seething and bubbling
without end. It is a drunken revel, an epidemic of delirium tremens.

Some, few as yet, emerging from the mass, climb to the opening by means
of the central pole or the walls of the enclosure. Will they take wing
and make their escape? Not they! Standing on the brink of the chasm,
almost free, they drop back into the whirlpool, in a fresh bout of
intoxication. The bait is irresistible. Not one of them will quit the
assembly until the evening, or perhaps next morning, when the heady
fumes have evaporated. Then the mass becomes disentangled; and the
insects extricate themselves from one another’s embraces and slowly, as
it were regretfully, leave the place and fly away. At the bottom of
this devil’s purse remains a heap of dead and dying, of severed limbs
and disjointed wing-cases, the inevitable result of the frenzied orgy.
Soon, Wood-lice, Earwigs and Ants will arrive and devour the deceased.

What were they doing there? Were they the prisoners of the flower? Had
it converted itself into a trap which allowed them to enter, but
prevented them from escaping, by means of a fence of converging hairs?
No, they were not prisoners; they had full liberty to go away, as is
shown by the final exodus, which is effected without impediment.
Deceived by a false odour, were they doing their best to instal their
eggs, as they would have done under a corpse? Not that either. There is
no trace of an attempt at egg-laying in the dragon’s purse. They came,
enticed by the smell of a dead body, their supreme delight; they were
drunk with corpse; and they spun round frantically in an undertakers’
carnival.

When the bacchanal dance is at its height, I try to count the number of
the arrivals. I rip up the floral pouch and pour its contents into a
flask. Absolutely tipsy though they be, many would escape during the
census, which I wish to take accurately. A few drops of carbon
bisulphide deprive the crowd of motion. The counting then shows that
there were over four hundred. Such was the living billow which I saw
surging just now in the dragon’s purse.

The throng consists entirely of two families, Dermestes and Saprini,
[45] both of whom are very busy in spring turning derelict corpses to
account. Here is a complete list of the visitors to a single flower,
with the number of representatives of each species: Dermestes Frischii,
Kugel., 120; D. undulatus, Brahm, 90; D. pardalis, Schoenh., 1;
Saprinus subnitidus, De Mars., 160; S. maculatus, Ross., 4; S.
detersus, Illig., 15; S. semipunctatus, De Mars., 12; S. œneus, Fabr.,
2; S. speculifer, Latr., 2. Total: 406.

Another detail deserves attention just as much as this enormous figure;
and that is the complete absence of a number of other genera which are
as passionately fond of small corpses as are the Dermestes and Saprini.
My charnel-houses of Moles never fail to be visited by the Silphæ and
Necrophori: Silpha sinuata, Fabr.; S. rugosa, Lin.; S. obscura, Lin.;
Necrophorus vestigator, Hersch. The reek of the dragon arum leaves them
all indifferent. None of them is represented in the ten flowers which I
examine.

Nor are any Diptera, those other devotees of corruption. Several Flies,
some grey or bluey, others a metallic green, come up, it is true,
settle on the edge of the flower and even find their way into the fetid
wallet; but they are almost immediately undeceived and fly away. Only
the Dermestes and Saprini stay behind. Why?

My friend Bull, as decent a Dog as ever lived, had this among many
other eccentricities: if he found in the dust of the road the dried up
corpse of a Mole flattened under the heels of the passers-by, mummified
by the heat of the sun, he would revel in rolling himself over it from
the tip of his nose to the end of his tail; he would rub himself in it
over and over again, shaken with nervous spasms, turning first on one
side, then on the other. It was his sachet of musk, his flask of
eau-de-Cologne. When scented to his liking, he would get up, shake
himself and trot off, pleased as Punch with his pomade. Let us not
abuse him and, above all, let us not discuss the matter. There are
tastes of all kinds in this world.

Why should not some of the insects that dote on the smell of the dead
have similar habits? Dermestes and Saprini come to the dragon arum; all
day long they swarm in throngs, although free to go away; many of them
die in the riot of the orgy. It is no rich provender that keeps them,
for the flower gives them nothing to eat; it is not a question of
laying eggs, for they take good care not to settle their grubs in that
famine-stricken spot. What are they doing here, the frenzied ones?
Apparently intoxicating themselves with fetidness, just as Bull did on
the carcass of a Mole.

And this intoxication of smell attracts them from every part around,
from very far perhaps, one cannot tell. Even so the Necrophori, in
quest of an establishment for their young, hasten from the fields to my
putrefying Moles. Both are informed by a potent smell, which offends
our nostrils sixty yards away, but which travels ahead and delights
them at distances where our own power of scent ceases.

The hydnocystis, the Bolboceras’ treat, has none of these violent
emanations, capable of being diffused through space; it is devoid of
smell, at least to us. The insect that hunts for it does not come from
a distance; it inhabits the very places where the cryptogam lies.
However faint the effluvia of the underground morsel, the prying
epicure, equipped for the purpose, has every facility for perceiving
them: he operates close by, on the surface of the soil. The Dog’s case
is the same: he goes along searching, with his nose to the ground.
Then, too, the real truffle, the essential object of his quest,
possesses a most pronounced odour.

But what are we to say of the Great Peacock and the Banded Monk, making
their way to the female born in captivity? They hasten from the ends of
the horizon. What do they perceive at that distance? Is it really an
odour, as our physiology understands the word? I cannot bring myself to
believe it.

The Dog smells the truffle by sniffing the earth, quite close to the
tuber; he finds his master at great distances by consulting the scent
of his footprints. But is he able to discover the truffle hundreds of
yards away, miles away? Can he join his master in the complete absence
of a trail? Certainly not. For all his fineness of scent, the Dog is
incapable of such a feat, which is performed, however by the Moth, who
is put off neither by distance nor by the lack of any traces out of
doors of the female hatched on my table.

It is a recognized fact that smell, ordinary smell, the smell that
affects our nostrils, consists of molecules emanating from the scented
body. The odorous matter dissolves and is diffused throughout the air
by communicating to the air its aroma, even as sugar dissolves and is
diffused in water by communicating to the water its sweetness. Smell
and taste touch each other at some points; in both cases there is a
contact between the material particles that give the impression and the
sensitive papillæ that receive it.

Nothing can be simpler or clearer than that the dragon arum elaborates
an intensely strong essence with which the air is impregnated and
infected all around. Thus the Dermestes and Saprini, those passionate
lovers of carrion smells, are informed by molecular diffusion. In the
same way, the putrid Toad gives out and disseminates the stinking atoms
that are the Necrophorus’ delight.

But what is materially emitted by the female Bombyx or Great Peacock?
Nothing, according to our sense of smell. And this nothing is supposed,
when the males congregate, to saturate an immense circle, several miles
in radius, with its molecules! What the horrible stench of the dragon
arum is unable to do the absence of odour is believed to accomplish!
However divisible matter may be, the mind refuses to accept such
conclusions. It would be tantamount to reddening a lake with an atom of
carmine, to filling immensity with nothing.

Another argument. When my study is saturated beforehand with pungent
odours which ought to overcome and destroy the most delicate effluvia,
the male Moths arrive without the least sign of embarrassment.

A loud noise kills the faint note and prevents it from being heard; a
bright light eclipses a feeble gleam. These are waves of the same
nature. But the roar of thunder cannot cause the least jet of light to
pale; nor can the dazzling glory of the sun stifle the least sound.
Being of different natures, light and sound do not influence each
other.

The experiment with the lavender-oil, naphthaline and the rest would
therefore seem to prove that odour proceeds from two sources. For
emission substitute undulation; and the problem of the Great Peacock is
explained. Without losing any of its substance, a luminous point shakes
the ether with its vibrations and fills a circle of indefinite width
with light. This must almost express the working of the mother Bombyx’
tell-tale discharge. It does not emit molecules: it vibrates; it sets
in motion waves capable of spreading to distances incompatible with a
real diffusion of matter.

In its entirety, smell would thus seem to have two domains: that of the
particles dissolved in the air and that of the ethereal waves. The
first alone is known to us. It belongs also to the insect. It is this
which informs the Saprinus of the dragon arum’s fetidity and the Silpha
and Necrophorus of the stench of the Mole.

The second, which is far superior in its range through space, escapes
us altogether, because we lack the necessary sensory equipment. The
Great Peacock and the Banded Monk know it at the time of the nuptial
rejoicings. And many others must share it in various degrees, according
to the exigencies of their mode of life.

Like light, odour has its X-rays. Should science one day, instructed by
the insect, endow us with a radiograph of smells, this artificial nose
will open out to us a world of marvels.



CHAPTER XIV

THE CABBAGE-CATERPILLAR


The cabbage of our modern kitchen-gardens is a semi-artificial plant,
the produce of our agricultural ingenuity quite as much as of the
niggardly gifts of nature. Spontaneous vegetation supplied us with the
long-stalked, scanty-leaved, ill-smelling wilding, as found, according
to the botanists, on the ocean cliffs. He had need of a rare
inspiration who first showed faith in this rustic clown and proposed to
improve it in his garden-patch.

Progressing by infinitesimal degrees, culture wrought miracles. It
began by persuading the wild cabbage to discard its wretched leaves,
beaten by the sea-winds, and to replace them by others, ample and
fleshy and close-fitting. The gentle cabbage submitted without protest.
It deprived itself of the joys of light by arranging its leaves in a
large, compact head, white and tender. In our day, among the successors
of those first tiny hearts, are some that, by virtue of their massive
bulk, have earned the glorious name of chou quintal, as who should say,
a hundredweight of cabbage. They are real monuments of green stuff.

Later, man thought of obtaining a generous dish with the thousand
little sprays of the inflorescence. The cabbage consented. Under the
cover of the central leaves, it gorged with food its sheaves of
blossom, its flower-stalks, its branches and worked the lot into a
fleshy conglomeration. This is the cauliflower, the broccoli.

Differently entreated, the plant, economizing in the centre of its
shoot, set a whole family of close-wrapped cabbages ladder-wise on a
tall stem. A multitude of dwarf leaf-buds took the place of the
colossal head. This is the Brussels sprout.

Next comes the turn of the stump, an unprofitable, almost wooden thing,
which seemed never to have any other purpose than to act as a support
for the plant. But the tricks of gardeners are capable of everything,
so much so that the stalk yields to the grower’s suggestions and
becomes fleshy and swells into an ellipse similar to the turnip, of
which it possesses all the merits of corpulence, flavour and delicacy;
only the strange product serves as a base for a few sparse leaves, the
last protests of a real stem that refuses to lose its attributes
entirely. This is the colerape.

If the stem allows itself to be allured, why not the root? It does in
fact, yield to the blandishments of agriculture: it dilates its pivot
into a flat turnip, which half emerges from the ground. This is the
rutabaga, or swede, the turnip-cabbage of our northern districts.

Incomparably docile under our nursing, the cabbage has given its all
for our nourishment and that of our cattle: its leaves, its flowers,
its buds, its stalk, its root; all that it now wants is to combine the
ornamental with the useful, to smarten itself, to adorn our flowerbeds
and cut a good figure on a drawing-room table. It has done this to
perfection, not with its flowers, which, in their modesty, continue
intractible, but with its curly and variegated leaves, which have the
undulating grace of Ostrich-feathers and the rich colouring of a mixed
bouquet. None who beholds it in this magnificence will recognize the
near relation of the vulgar “greens” that form the basis of our
cabbage-soup.

The cabbage, first in order of date in our kitchen-gardens, was held in
high esteem by classic antiquity, next after the bean and, later, the
pea; but it goes much farther back, so far indeed that no memories of
its acquisition remain. History pays but little attention to these
details: it celebrates the battle-fields whereon we meet our death, it
scorns to speak of the ploughed fields whereby we thrive; it knows the
names of the kings’ bastards, it cannot tell us the origin of wheat.
That is the way of human folly.

This silence respecting the precious plants that serve as food is most
regrettable. The cabbage in particular, the venerable cabbage, that
denizen of the most ancient garden-plots, would have had extremely
interesting things to teach us. It is a treasure in itself, but a
treasure twice exploited, first by man and next by the caterpillar of
the Pieris, the common Large White Butterfly whom we all know (Pieris
brassicæ, Lin.). This caterpillar feeds indiscriminately on the leaves
of all varieties of cabbage, however dissimilar in appearance: he
nibbles with the same appetite red cabbage and broccoli, curly greens
and savoy, swedes and turnip-tops, in short, all that our ingenuity,
lavish of time and patience, has been able to obtain from the original
plant since the most distant ages.

But what did the caterpillar eat before our cabbages supplied him with
copious provender? Obviously the Pieris did not wait for the advent of
man and his horticultural works in order to take part in the joys of
life. She lived without us and would have continued to live without us.
A Butterfly’s existence is not subject to ours, but rightfully
independent of our aid.

Before the white-heart, the cauliflower, the savoy and the others were
invented, the Pieris’ caterpillar certainly did not lack food: he
browsed the wild cabbage of the cliffs, the parent of all the
latter-day wealth; but, as this plant is not widely distributed and is,
in any case, limited to certain maritime regions, the welfare of the
Butterfly, whether on plain or hill, demanded a more luxuriant and more
common plant for pasturage. This plant was apparently one of the
Cruciferæ, more or less seasoned with sulphuretted essence, like the
cabbages. Let us experiment on these lines.

I rear the Pieris’ caterpillars from the egg upwards on the wall-rocket
(Diplotaxis tenuifolia, Dec.), which imbibes strong spices along the
edge of the paths and at the foot of the walls. Penned in a large,
wire-gauze bell-cage, they accept this provender without demur; they
nibble it with the same appetite as if it were cabbage; and they end by
producing chrysalids and Butterflies. The change of fare causes not the
least trouble.

I am equally successful with other crucifers of a less marked flavour:
white mustard (Sinapis incana, Lin.), dyer’s woad (Isatis tinctoria,
Lin.), wild radish (Raphanus raphanistrum, Lin.), whitlow pepperwort
(Lepidium draba, Lin.), hedge-mustard (Sisymbrium officinale, Scop.).
On the other hand, the leaves of the lettuce, the bean, the pea, the
corn-salad are obstinately refused. Let us be content with what we have
seen: the fare has been sufficiently varied to show us that the
Cabbage-caterpillar feeds exclusively on a large number of crucifers,
perhaps even on all.

As these experiments are made in the enclosure of a bell-cage, one
might imagine that captivity impels the flock to feed, in the absence
of better things, on what it would refuse were it free to hunt for
itself. Having naught else within their reach, the starvelings consume
any and all Cruciferæ, without distinction of species. Can things
sometimes be the same in the open fields, where I play none of my
tricks? Can the family of the White Butterfly be settled on other
crucifers than the cabbage? I start a quest along the paths near the
gardens and end by finding on wild radish and white mustard colonies as
crowded and prosperous as those established on cabbage.

Now, except when the metamorphosis is at hand, the caterpillar of the
White Butterfly never travels: he does all his growing on the identical
plant whereon he saw the light. The caterpillars observed on the wild
radish, as well as other households, are not, therefore, emigrants who
have come as a matter of fancy from some cabbage-patch in the
neighbourhood: they have hatched on the very leaves where I find them.
Hence I arrive at this conclusion: the White Butterfly, who is fitful
in her flight, chooses cabbage first, to dab her eggs upon, and
different Cruciferæ next, varying greatly in appearance.

How does the Pieris manage to know her way about her botanical domain?
We have seen the Larini, [46] those explorers of fleshy receptacles
with an artichoke flavour, astonish us with their knowledge of the
flora of the thistle tribe; but their lore might, at a pinch, be
explained by the method followed at the moment of housing the egg. With
their rostrum, they prepare niches and dig out basins in the receptacle
exploited and consequently they taste the thing a little before
entrusting their eggs to it. On the other hand, the Butterfly, a
nectar-drinker, makes not the least enquiry into the savoury qualities
of the leafage; at most, dipping her proboscis into the flowers, she
abstracts a mouthful of syrup. This means of investigation, moreover,
would be of no use to her, for the plant selected for the establishing
of her family is, for the most part, not yet in flower. The mother
flits for a moment around the plant; and that swift examination is
enough: the emission of eggs takes place if the provender be found
suitable.

The botanist, to recognize a crucifer, requires the indications
provided by the flower. Here the Pieris surpasses us. She does not
consult the seed-vessel, to see if it be long or short, nor yet the
petals, four in number and arranged in a cross, because the plant, as a
rule, is not in flower; and still she recognizes off-hand what suits
her caterpillars, in spite of profound differences that would embarrass
any but a botanical expert.

Unless the Pieris has an innate power of discrimination to guide her,
it is impossible to understand the great extent of her vegetable realm.
She needs for her family Cruciferæ, nothing but Cruciferæ; and she
knows this group of plants to perfection. I have been an enthusiastic
botanist for half a century and more. Nevertheless, to discover if this
or that plant, new to me, is or is not one of the Cruciferæ, in the
absence of flowers and fruits I should have more faith in the
Butterfly’s statements than in all the learned records of the books.
Where science is apt to make mistakes, instinct is infallible.

The Pieris has two families a year: one in April and May, the other in
September. The cabbage-patches are renewed in those same months. The
Butterfly’s calendar tallies with the gardener’s: the moment that
provisions are in sight, consumers are forthcoming for the feast.

The eggs are a bright orange-yellow and do not lack prettiness when
examined under the lens. They are blunted cones, ranged side by side on
their round base and adorned with finely-scored longitudinal ridges.
They are collected in slabs, sometimes on the upper surface, when the
leaf that serves as a support is spread wide, sometimes on the lower
surface when the leaf is pressed to the next ones. Their number varies
considerably. Slabs of a couple of hundred are pretty frequent;
isolated eggs, or eggs collected in small groups, are, on the contrary,
rare. The mother’s output is affected by the degree of quietness at the
moment of laying.

The outer circumference of the group is irregularly formed, but the
inside presents a certain order. The eggs are here arranged in straight
rows backing against one another in such a way that each egg finds a
double support in the preceding row. This alternation, without being of
an irreproachable precision, gives a fairly stable equilibrium to the
whole.

To see the mother at her laying is no easy matter: when examined too
closely, the Pieris decamps at once. The structure of the work,
however, reveals the order of the operations pretty clearly. The
ovipositor swings slowly first in this direction, then in that, by
turns; and a new egg is lodged in each space between two adjoining eggs
in the previous row. The extent of the oscillation determines the
length of the row, which is longer or shorter according to the layer’s
fancy.

The hatching takes place in about a week. It is almost simultaneous for
the whole mass: as soon as one caterpillar comes out of its egg, the
others come out also, as though the natal impulse were communicated
from one to the other. In the same way, in the nest of the Praying
Mantis, a warning seems to be spread abroad, arousing every one of the
population. It is a wave propagated in all directions from the point
first struck.

The egg does not open by means of a dehiscence similar to that of the
vegetable-pods whose seeds have attained maturity; it is the new-born
grub itself that contrives an exit-way by gnawing a hole in its
enclosure. In this manner, it obtains near the top of the cone a
symmetrical dormer-window, clean-edged, with no joins nor unevenness of
any kind, showing that this part of the wall has been nibbled away and
swallowed. But for this breach, which is just wide enough for the
deliverance, the egg remains intact, standing firmly on its base. It is
now that the lens is best able to take in its elegant structure. What
it sees is a bag made of ultra-fine goldbeater’s-skin, translucent,
stiff and white, retaining the complete form of the original egg. A
score of streaked and knotted lines run from the top to the base. It is
the wizard’s pointed cap, the mitre with the grooves carved into
jewelled chaplets. All said, the Cabbage-caterpillar’s birth-casket is
an exquisite work of art.

The hatching of the lot is finished in a couple of hours and the
swarming family musters on the layer of swaddling-clothes, still in the
same position. For a long time, before descending to the fostering
leaf, it lingers on this kind of hot-bed, is even very busy there. Busy
with what? It is browsing a strange kind of grass, the handsome mitres
that remain standing on end. Slowly and methodically, from top to base,
the new-born grubs nibble the wallets whence they have just emerged. By
to-morrow, nothing is left of these but a pattern of round dots, the
bases of the vanished sacks.

As his first mouthfuls, therefore, the Cabbage-caterpillar eats the
membranous wrapper of his egg. This is a regulation diet, for I have
never seen one of the little grubs allow itself to be tempted by the
adjacent green stuff before finishing the ritual repast whereat skin
bottles furnish forth the feast. It is the first time that I have seen
a larva make a meal of the sack in which it was born. Of what use can
this singular fare be to the budding caterpillar? I suspect as follows:
the leaves of the cabbage are waxed and slippery surfaces and nearly
always slant considerably. To graze on them without risking a fall,
which would be fatal in earliest childhood, is hardly possible unless
with moorings that afford a steady support. What is needed is bits of
silk stretched along the road as fast as progress is made, something
for the legs to grip, something to provide a good anchorage even when
the grub is upside down. The silk-tubes, where those moorings are
manufactured, must be very scantily supplied in a tiny, new-born
animal; and it is expedient that they be filled without delay with the
aid of a special form of nourishment. Then what shall the nature of the
first food be? Vegetable matter, slow to elaborate and niggardly in its
yield, does not fulfil the desired conditions at all well, for time
presses and we must trust ourselves safely to the slippery leaf. An
animal diet would be preferable: it is easier to digest and undergoes
chemical changes in a shorter time. The wrapper of the egg is of a
horny nature, as silk itself is. It will not take long to transform the
one into the other. The grub therefore tackles the remains of its egg
and turns it into silk to carry with it on its first journeys.

If my surmise is well-founded, there is reason to believe that, with a
view to speedily filling the silk-glands to which they look to supply
them with ropes, other caterpillars beginning their existence on smooth
and steeply-slanting leaves also take as their first mouthful the
membranous sack which is all that remains of the egg.

The whole of the platform of birth-sacks which was the first
camping-ground of the White Butterfly’s family is razed to the ground;
naught remains but the round marks of the individual pieces that
composed it. The structure of piles has disappeared; the prints left by
the piles remain. The little caterpillars are now on the level of the
leaf which shall henceforth feed them. They are a pale orange-yellow,
with a sprinkling of white bristles. The head is a shiny black and
remarkably powerful; it already gives signs of the coming gluttony. The
little animal measures scarcely two millimetres [47] in length.

The troop begins its steadying-work as soon as it comes into contact
with its pasturage, the green cabbage-leaf. Here, there, in its
immediate neighbourhood, each grub emits from its spinning-glands short
cables so slender that it takes an attentive lens to catch a glimpse of
them. This is enough to ensure the equilibrium of the almost
imponderable atom.

The vegetarian meal now begins. The grub’s length promptly increases
from two millimetres to four. Soon, a moult takes place which alters
its costume: its skin becomes speckled, on a pale-yellow ground, with a
number of black dots intermingled with white bristles. Three or four
days of rest are necessary after the fatigue of breaking cover. When
this is over, the hunger-fit starts that will make a ruin of the
cabbage within a few weeks.

What an appetite! What a stomach, working continuously day and night!
It is a devouring laboratory, through which the foodstuffs merely pass,
transformed at once. I serve up to my caged herd a bunch of leaves
picked from among the biggest: two hours later, nothing remains but the
thick midribs; and even these are attacked when there is any delay in
renewing the victuals. At this rate, a “hundredweight-cabbage,” doled
out leaf by leaf, would not last my menagerie a week.

The gluttonous animal, therefore, when it swarms and multiplies, is a
scourge. How are we to protect our gardens against it? In the days of
Pliny, the great Latin naturalist, a stake was set up in the middle of
the cabbage-bed to be preserved; and on this stake was fixed a Horse’s
skull bleached in the sun: a Mare’s skull was considered even better.
This sort of bogey was supposed to ward off the devouring brood.

My confidence in this preservative is but an indifferent one; my reason
for mentioning it is that it reminds me of a custom still observed in
our own days, at least in my part of the country. Nothing is so
long-lived as absurdity. Tradition has retained, in a simplified form,
the ancient defensive apparatus of which Pliny speaks. For the Horse’s
skull our people have substituted an eggshell on the top of a switch
stuck among the cabbages. It is easier to arrange; also, it is quite as
useful, that is to say, it has no effect whatever.

Everything, even the nonsensical, is capable of explanation with a
little credulity. When I question the peasants, our neighbours, they
tell me that the effect of the eggshell is as simple as can be: the
Butterflies, attracted by the whiteness, come and lay their eggs on it.
Broiled by the sun and lacking all nourishment on that thankless
support, the little caterpillars die; and that makes so many fewer.

I insist; I ask them if they have ever seen slabs of eggs or masses of
young caterpillars on those white shells.

“Never,” they reply, with one voice.

“Well, then?”

“It was done in the old days and so we go on doing it: that’s all we
know; and that’s enough for us.”

I leave it at that, persuaded that the memory of the Horse’s skull used
once upon a time is ineradicable, like all the rustic absurdities
implanted by the ages.

We have, when all is said, but one means of protection, which is to
watch and inspect the cabbage-leaves assiduously and crush the slabs of
eggs between our finger and thumb and the caterpillars with our feet.
Nothing is so effective as this method, which makes great demands on
one’s time and vigilance. What pains to obtain an unspoilt cabbage! And
what a debt do we not owe to those humble scrapers of the soil, those
ragged heroes who provide us with the wherewithal to live!

To eat and digest, to accumulate reserves whence the Butterfly will
issue: that is the caterpillar’s one and only business. The
Cabbage-caterpillar performs it with insatiable gluttony. Incessantly
it browses, incessantly digests: the supreme felicity of an animal
which is little more than an intestine. There is never a distraction,
unless it be certain see-saw movements which are particularly curious
when several caterpillars are grazing side by side, abreast. Then, at
intervals, all the heads in the row are briskly lifted and as briskly
lowered, time after time, with an automatic precision worthy of a
Prussian drill-ground. Can it be their method of intimidating an always
possible aggressor? Can it be a manifestation of gaiety, when the
wanton sun warms their full paunches? Whether sign of fear or sign of
bliss, this is the only exercise that the gluttons allow themselves
until the proper degree of plumpness is attained.

After a month’s grazing, the voracious appetite of my caged herd is
assuaged. The caterpillars climb the trelliswork in every direction,
walk about anyhow, with their fore-part raised and searching space.
Here and there, as they pass, the swaying herd put forth a thread. They
wander restlessly, anxiously to travel afar. The exodus now prevented
by the trellised enclosure I once saw under excellent conditions. At
the advent of the cold weather, I had placed a few cabbage-stalks,
covered with caterpillars, in a small greenhouse. Those who saw the
common kitchen vegetable sumptuously lodged under glass, in the company
of the pelargonium and the Chinese primrose, were astonished at my
curious fancy. I let them smile. I had my plans: I wanted to find out
how the family of the Large White Butterfly behaves when the cold
weather sets in. Things happened just as I wished. At the end of
November, the caterpillars, having grown to the desired extent, left
the cabbages, one by one, and began to roam about the walls. None of
them fixed himself there or made preparations for the transformation. I
suspected that they wanted the choice of a spot in the open air,
exposed to all the rigours of winter. I therefore left the door of the
hothouse open. Soon, the whole crowd had disappeared.

I found them dispersed all over the neighbouring walls, some thirty
yards off. The thrust of a ledge, the eaves formed by a projecting bit
of mortar served them as a shelter where the chrysalid moult took place
and where the winter was passed. The Cabbage-caterpillar possesses a
robust constitution, unsusceptible to torrid heat or icy cold. All that
he needs for his metamorphosis is an airy lodging, free from permanent
damp.

The inmates of my fold, therefore, move about for a few days on the
trelliswork, anxious to travel afar in search of a wall. Finding none
and realizing that time presses, they resign themselves. Each one,
supporting himself on the trellis, first weaves around himself a thin
carpet of white silk, which will form the sustaining layer at the time
of the laborious and delicate work of the nymphosis. He fixes his
rear-end to this base by a silk pad and his fore-part by a strap that
passes under his shoulders and is fixed on either side to the carpet.
Thus slung from his three fastenings, he strips himself of his larval
apparel and turns into a chrysalis in the open air, with no protection
save that of the wall, which the caterpillar would certainly have found
had I not interfered.

Of a surety, he would be short-sighted indeed that pictured a world of
good things prepared exclusively for our advantage. The earth, the
great foster-mother, has a generous breast. At the very moment when
nourishing matter is created, even though it be with our own zealous
aid, she summons to the feast host upon host of consumers, who are all
the more numerous and enterprising in proportion as the table is more
amply spread. The cherry of our orchards is excellent eating: a maggot
contends with us for its possession. In vain do we weigh suns and
planets: our supremacy, which fathoms the universe, cannot prevent a
wretched worm from levying its toll on the delicious fruit. We make
ourselves at home in a cabbage-bed: the sons of the Pieris make
themselves at home there too. Preferring broccoli to wild radish, they
profit where we have profited; and we have no remedy against their
competition save caterpillar-raids and egg-crushing, a thankless,
tedious and none too efficacious work.

Every creature has its claims on life. The Cabbage-caterpillar eagerly
puts forth his own, so much so that the cultivation of the precious
plant would be endangered if others concerned did not take part in its
defence. These others are the auxiliaries, [48] our helpers from
necessity and not from sympathy. The words friend and foe, auxiliaries
and ravagers are here the mere conventions of a language not always
adapted to render the exact truth. He is our foe who eats or attacks
our crops; our friend is he who feeds upon our foes. Everything is
reduced to a frenzied contest of appetites.

In the name of the might that is mine, of trickery, of highway robbery,
clear out of that, you, and make room for me: give me your seat at the
banquet! That is the inexorable law in the world of animals and more or
less, alas, in our own world as well!

Now, among our entomological auxiliaries, the smallest in size are the
best at their work. One of them is charged with watching over the
cabbages. She is so small, she works so discreetly that the gardener
does not know her, has not even heard of her. Were he to see her by
accident, flitting around the plant which she protects, he would take
no notice of her, would not suspect the service rendered. I propose to
set forth the tiny midget’s deserts.

Scientists call her Microgaster glomeratus. What exactly was in the
mind of the author of the name Microgaster, which means little belly?
Did he intend to allude to the insignificance of the abdomen? Not so.
However slight the belly may be, the insect nevertheless possesses one,
correctly proportioned to the rest of the body, so that the classic
denomination, far from giving us any information, might mislead us,
were we to trust it wholly. Nomenclature, which changes from day to day
and becomes more and more cacophonous, is an unsafe guide. Instead of
asking the animal what its name is, let us begin by asking:

“What can you do? What is your business?”

Well, the Microgaster’s business is to exploit the Cabbage-caterpillar,
a clearly-defined business, admitting of no possible confusion. Would
we behold her works? In the spring, let us inspect the neighbourhood of
the kitchen-garden. Be our eye never so unobservant, we shall notice
against the walls or on the withered grasses at the foot of the hedges
some very small yellow cocoons, heaped into masses the size of a
hazel-nut. Beside each group lies a Cabbage-caterpillar, sometimes
dying, sometimes dead and always presenting a most tattered appearance.
These cocoons are the work of the Microgaster’s family, hatched or on
the point of hatching into the perfect stage; the caterpillar is the
dish whereon that family has fed during its larval state. The epithet
glomeratus, which accompanies the name of Microgaster, suggests this
conglomeration of cocoons. Let us collect the clusters as they are,
without seeking to separate them, an operation which would demand both
patience and dexterity, for the cocoons are closely united by the
inextricable tangle of their surface-threads. In May, a swarm of
pigmies will sally forth, ready to get to business in the cabbages.

Colloquial language uses the terms Midge and Gnat to describe the tiny
insects which we often see dancing in a ray of sunlight. There is
something of everything in those aerial ballets. It is possible that
the persecutrix of the Cabbage-caterpillar is there, along with many
another; but the name of Midge cannot properly be applied to her. He
who says Midge says Fly, Dipteron, two-winged insect; and our friend
has four wings, one and all adapted for flying. By virtue of this
characteristic and others no less important, she belongs to the order
of Hymenoptera. [49] No matter: as our language possesses no more
precise term outside the scientific vocabulary, let us use the
expression Midge, which pretty well conveys the general idea. Our
Midge, the Microgaster, is the size of an average Gnat. She measures 3
or 4 millimetres. [50] The two sexes are equally numerous and wear the
same costume, a black uniform, all but the legs, which are pale red. In
spite of this likeness, they are easily distinguished. The male has an
abdomen which is slightly flattened and moreover curved at the tip; the
female, before the laying, has hers full and perceptibly distended by
its ovular contents. This rapid sketch of the insect should be enough
for our purpose.

If we wish to know the grub and especially to inform ourselves of its
manner of living, it is advisable to rear in a cage a numerous herd of
Cabbage-caterpillars. Whereas a direct search on the cabbages in our
garden would give us but a difficult and uncertain harvest, by this
means we shall daily have as many as we wish before our eyes.

In the course of June, which is the time when the caterpillars quit
their pastures and go far afield to settle on some wall or other, those
in my fold, finding nothing better, climb to the dome of the cage to
make their preparations and to spin a supporting network for the
chrysalid’s needs. Among these spinners we see some weaklings working
listlessly at their carpet. Their appearance makes us deem them in the
grip of a mortal disease. I take a few of them and open their bellies,
using a needle by way of a scalpel. What comes out is a bunch of green
entrails, soaked in a bright yellow fluid, which is really the
creature’s blood. These tangled intestines swarm with little, lazy
grubs, varying greatly in number, from ten or twenty at least to
sometimes half-a-hundred. They are the offspring of the Microgaster.

What do they feed on? The lens makes conscientious enquiries; nowhere
does it manage to show me the vermin attacking solid nourishment, fatty
tissues, muscles or other parts; nowhere do I see them bite, gnaw or
dissect. The following experiment will tell us more fully: I pour into
a watch-glass the crowds extracted from the hospitable paunches. I
flood them with caterpillar’s blood obtained by simple pricks; I place
the preparation under a glass bell-jar, in a moist atmosphere, to
prevent evaporation; I repeat the nourishing bath by means of fresh
bleedings and give them the stimulant which they would have gained from
the living caterpillar. Thanks to these precautions, my charges have
all the appearance of excellent health; they drink and thrive. But this
state of things cannot last long. Soon ripe for the transformation, my
grubs leave the dining-room of the watch-glass as they would have left
the caterpillar’s belly; they come to the ground to try and weave their
tiny cocoons. They fail in the attempt and perish. They have missed a
suitable support, that is to say, the silky carpet provided by the
dying caterpillar. No matter: I have seen enough to convince me. The
larvae of the Microgaster do not eat in the strict sense of the word:
they live on soup; and that soup is the caterpillar’s blood.

Examine the parasites closely and you shall see that their diet is
bound to be a liquid one. They are little white grubs, neatly
segmented, with a pointed fore-part splashed with tiny black marks, as
though the atom had been slaking its thirst in a drop of ink. It moves
its hind-quarters slowly, without shifting its position. I place it
under the microscope. The mouth is a pore, devoid of any apparatus for
disintegration-work: it has no fangs, no horny nippers, no mandibles;
its attack is just a kiss. It does not chew, it sucks, it takes
discreet sips at the moisture all around it.

The fact that it refrains entirely from biting is confirmed by my
autopsy of the stricken caterpillars. In the patient’s belly,
notwithstanding the number of nurselings who hardly leave room for the
nurse’s entrails, everything is in perfect order; nowhere do we see a
trace of mutilation. Nor does aught on the outside betray any havoc
within. The exploited caterpillars graze and move about peacefully,
giving no sign of pain. It is impossible for me to distinguish them
from the unscathed ones in respect of appetite and untroubled
digestion.

When the time approaches to weave the carpet for the support of the
chrysalis, an appearance of emaciation at last points to the evil that
is at their vitals. They spin nevertheless. They are stoics who do not
forget their duty in the hour of death. At last, they expire, quite
softly, not of any wounds, but of anæmia, even as a lamp goes out when
the oil comes to an end. And it has to be. The living caterpillar,
capable of feeding itself and forming blood, is a necessity for the
welfare of the grubs; it has to last about a month, until the
Microgaster’s offspring have achieved their full growth. The two
calendars synchronize in a remarkable way. When the caterpillar leaves
off eating and makes its preparations for the metamorphosis, the
parasites are ripe for the exodus. The bottle dries up when the
drinkers cease to need it; but until that moment it must remain more or
less well-filled, although becoming limper daily. It is important,
therefore, that the caterpillar’s existence be not endangered by wounds
which, even though very tiny, would stop the working of the
blood-fountains. With this intent, the drainers of the bottle are, in a
manner of speaking, muzzled; they have by way of a mouth a pore that
sucks without bruising.

The dying caterpillar continues to lay the silk of his carpet with a
slow oscillation of the head. The moment now comes for the parasites to
emerge. This happens in June and generally at nightfall. A breach is
made on the ventral surface or else in the sides, never on the back:
one breach only, contrived at a point of minor resistance, at the
junction of two segments; for it is bound to be a toilsome business, in
the absence of a set of filing-tools. Perhaps the worms take one
another’s places at the point attacked and come by turns to work at it
with a kiss.

In one short spell, the whole tribe issues through this single opening
and is soon wriggling about, perched on the surface of the caterpillar.
The lens cannot perceive the hole, which closes on the instant. There
is not even a hæmorrhage: the bottle has been drained too thoroughly.
You must press it between your fingers to squeeze out a few drops of
moisture and thus discover the spot of exit.

Around the caterpillar, who is not always quite dead and who sometimes
even goes on weaving his carpet a moment longer, the vermin at once
begin to work at their cocoons. The straw-coloured thread, drawn from
the silk-glands by a backward jerk of the head, is first fixed to the
white network of the caterpillar and then produces adjacent warp-beams,
so that, by mutual entanglements, the individual works are welded
together and form an agglomeration in which each of the worms has its
own cabin. For the moment, what is woven is not the real cocoon, but a
general scaffolding which will facilitate the construction of the
separate shells. All these frames rest upon those adjoining and, mixing
up their threads, become a common edifice wherein each grub contrives a
shelter for itself. Here at last the real cocoon is spun, a pretty
little piece of closely-woven work.

In my rearing-jars, I obtain as many groups of those tiny shells as my
future experiments can wish for. Three-fourths of the caterpillars have
supplied me with them, so ruthless has been the toll of the spring
births. I lodge these groups, one by one, in separate glass tubes, thus
forming a collection on which I can draw at will, while, in view of my
experiments, I keep under observation the whole swarm produced by one
caterpillar.

The adult Microgaster appears a fortnight later, in the middle of June.
There are fifty in the first tube examined. The riotous multitude is in
the full enjoyment of the pairing-season, for the two sexes always
figure among the guests of any one caterpillar. What animation! What an
orgy of love! The carnival of those pigmies bewilders the observer and
makes his head swim.

Most of the females, wishful of liberty, plunge down to the waist
between the glass of the tube and the plug of cotton-wool that closes
the end turned to the light; but the lower halves remain free and form
a circular gallery in front of which the males hustle one another, take
one another’s places and hastily operate. Each bides his turn, each
attends to his little matters for a few moments and then makes way for
his rivals and goes off to start again elsewhere. The turbulent wedding
lasts all the morning and begins afresh next day, a mighty throng of
couples embracing, separating and embracing once more.

There is every reason to believe that, in gardens, the mated ones,
finding themselves in isolated couples, would keep quieter. Here, in
the tube, things degenerate into a riot because the assembly is too
numerous for the narrow space.

What is lacking to complete its happiness? Apparently, a little food, a
few sugary mouthfuls extracted from the flowers. I serve up some
provisions in the tubes: not drops of honey, in which the puny
creatures would get stuck, but little strips of paper spread with that
dainty. They come to them, take their stand on them and refresh
themselves. The fare appears to agree with them. With this diet,
renewed as the strips dry up, I can keep them in very good condition
until the end of my inquisition.

There is another arrangement to be made. The colonists in my spare
tubes are restless and quick of flight; they will have to be
transferred presently to sundry vessels without my risking the loss of
a good number, or even the whole lot, a loss which my hands, my forceps
and other means of coercion would be unable to prevent by checking the
nimble movements of the tiny prisoners. The irresistible attraction of
the sunlight comes to my aid. If I lay one of my tubes horizontally on
the table, turning one end towards the full light of a sunny window,
the captives at once make for this brighter end and play about there
for a long while, without seeking to retreat. If I turn the tube in the
opposite direction, the crowd immediately shifts its quarters and
collects at the other end. The brilliant sunlight is its great joy.
With this bait, I can send it whithersoever I please.

We will therefore place the new receptacle, jar or test-tube, on the
table, pointing the closed end towards the window. At its mouth, we
open one of the full tubes. No other precaution is needed: even though
the mouth leaves a large interval free, the swarm hastens into the
lighted chamber. All that remains to be done is to close the apparatus
before moving it. The observer is now in control of the multitude,
without appreciable losses, and is able to question it at will.

We will begin by asking:

“How do you manage to lodge your germs inside the caterpillar?”

This question and others of the same category, which ought to take
precedence of everything else, are generally neglected by the impaler
of insects, who cares more for the niceties of nomenclature than for
glorious realities. He classifies his subjects, dividing them into
regiments with barbarous labels, a work which seems to him the highest
expression of entomological science. Names, nothing but names: the rest
hardly counts. The persecutor of the Pieris used to be called
Microgaster, that is to say, little belly: to-day she is called
Apantales, that is to say, the incomplete. What a fine step forward! We
now know all about it!

Can our friend at least tell us how “the little belly” or “the
incomplete” gets into the caterpillar? Not a bit of it! A book which,
judging by its recent date, should be the faithful echo of our actual
knowledge, informs us that the Microgaster inserts her eggs direct into
the caterpillar’s body. It goes on to say that the parasitic vermin
inhabit the chrysalis, whence they make their way out by perforating
the stout horny wrapper. Hundreds of times have I witnessed the exodus
of the grubs ripe for weaving their cocoons; and the exit has always
been made through the skin of the caterpillar and never through the
armour of the chrysalis. The fact that its mouth is a mere clinging
pore, deprived of any offensive weapon, would even lead me to believe
that the grub is incapable of perforating the chrysalid’s covering.

This proved error makes me doubt the other proposition, though logical,
after all, and agreeing with the methods followed by a host of
parasites. No matter: my faith in what I read in print is of the
slightest; I prefer to go straight to facts. Before making a statement
of any kind, I want to see, what I call seeing. It is a slower and more
laborious process; but it is certainly much safer.

I will not undertake to lie in wait for what takes place on the
cabbages in the garden: that method is too uncertain and besides does
not lend itself to precise observation. As I have in hand the necessary
materials, to wit, my collection of tubes swarming with the parasites
newly hatched into the adult form, I will operate on the little table
in my animals’ laboratory. A jar with a capacity of about a litre [51]
is placed on the table, with the bottom turned towards the window in
the sun. I put into it a cabbage-leaf covered with caterpillars,
sometimes fully developed, sometimes half-way, sometimes just out of
the egg. A strip of honeyed paper will serve the Microgaster as a
dining-room, if the experiment is destined to take some time. Lastly,
by the method of transfer which I described above, I send the inmates
of one of my tubes into the apparatus. Once the jar is closed, there is
nothing left to do but to let things take their course and to keep an
assiduous watch, for days and weeks, if need be. Nothing worth
remarking can escape me.

The caterpillars graze placidly, heedless of their terrible attendants.
If some giddy-pates in the turbulent swarm pass over the caterpillars’
spines, these draw up their fore-part with a jerk and as suddenly lower
it again; and that is all: the intruders forthwith decamp. Nor do the
latter seem to contemplate any harm: they refresh themselves on the
honey-smeared strip, they come and go tumultuously. Their short flights
may land them, now in one place, now in another, on the browsing herd,
but they pay no attention to it. What we see is casual meetings, not
deliberate encounters.

In vain I change the flock of caterpillars and vary their age; in vain
I change the squad of parasites: in vain I follow events in the jar for
long hours, morning and evening, both in a dim light and in the full
glare of the sun: I succeed in seeing nothing, absolutely nothing, on
the parasite’s side, that resembles an attack. No matter what the
ill-informed authors say—ill-informed because they had not the patience
to see for themselves—the conclusion at which I arrive is positive: to
inject the germs, the Microgaster never attacks the caterpillars.

The invasion, therefore, is necessarily effected through the
Butterfly’s eggs themselves, as experiment will prove. My broad jar
would tell against the inspection of the troop, kept at too great a
distance by the glass enclosure; and I therefore select a tube an inch
wide. I place in this a shred of cabbage-leaf, bearing a slab of eggs,
as laid by the Butterfly. I next introduce the inmates of one of my
spare vessels. A strip of paper smeared with honey accompanies the new
arrivals.

This happens early in July. Soon, the females are there, fussing about,
sometimes to the extent of blackening the whole slab of yellow eggs.
They inspect the treasure, flutter their wings and brush their
hind-legs against each other, a sign of keen satisfaction. They sound
the heap, probe the interstices with their antennae and tap the
individual eggs with their palpi; then, this one here, that one there,
they quickly apply the tip of their abdomen to the egg selected. Each
time, we see a slender, horny prickle darting from the ventral surface,
close to the end. This is the instrument that deposits the germ under
the film of the egg; it is the inoculation-needle. The operation is
performed calmly and methodically, even when several mothers are
working at one and the same time. Where one has been, a second goes,
followed by a third, a fourth and others yet, nor am I able definitely
to see the end of the visits paid to the same egg. Each time, the
needle enters and inserts a germ.

It is impossible, in such a crowd, for the eye to follow the successive
mothers who hasten to lay in each; but there is one quite practicable
method by which we can estimate the number of germs introduced into a
single egg, which is, later, to open the ravaged caterpillars and count
the worms which they contain. A less repugnant means is to number the
little cocoons heaped up around each dead caterpillar. The total will
tell us how many germs were injected, some by the same mother returning
several times to the egg already treated, others by different mothers.
Well, the number of these cocoons varies greatly. Generally, it
fluctuates in the neighbourhood of twenty, but I have come across as
many as sixty-five; and nothing tells me that this is the extreme
limit. What hideous industry for the extermination of a Butterfly’s
progeny!

I am fortunate at this moment in having a highly-cultured visitor,
versed in the profundities of philosophic thought. I make way for him
before the apparatus wherein the Microgaster is at work. For an hour
and more, standing lens in hand, he, in his turn, looks and sees what I
have just seen; he watches the layers who go from one egg to the other,
make their choice, draw their slender lancet and prick what the stream
of passers-by, one after the other, have already pricked. Thoughtful
and a little uneasy, he puts down his lens at last. Never had he been
vouchsafed so clear a glimpse as here, in my finger-wide tube, of the
masterly brigandage that runs through all life down to that of the very
smallest.



NOTES


[1] René Antoine Ferchault de Réaumur (1683–1757), inventor of the
Réaumur thermometer and author of Mémoires pour servir à l’histoire
naturelle des insectes.—Translator’s Note.

[2] For the Cicada or Cigale, an insect remotely akin to the
Grasshopper and found more particularly in the south of France, cf.
Social Life in the Insect World, by J. H. Fabre, translated by Bernard
Miall: chaps. i to iv.—Translator’s Note.

[3] The harmas was the enclosed piece of waste ground in which the
author used to study his insects in their natural state.—Translator’s
Note.

[4] The eponymous hero of Voltaire’s story of “the little great man,”
published in 1752 in imitation of Gulliver’s Travels.—Translator’s
Note.

[5] .039 inch.—Translator’s Note.

[6] About three-quarters of an inch.—Translator’s Note.

[7] .117 to .156 inch.—Translator’s Note.

[8] In the course of an essay on aberration of instinct in a certain
Mason-wasp which is not yet translated into English.—Translator’s Note.

[9] A predatory insect, akin to the Locusts and Crickets, which, when
at rest, adopts an attitude resembling that of prayer. Cf. Social Life
in the Insect World: chaps. v to vii.—Translator’s Note.

[10] The order of insects embracing the Bees, Wasps, Ants, Saw-flies,
Ichneumon-flies, etc.—Translator’s Note.

[11] Cf. The Mason-bees, by J. Henri Fabre, translated by Alexander
Teixeira de Mattos, passim.—Translator’s Note.

[12] White Ants.—Translator’s Note.

[13] Book IV., chap. viii.—Translator’s Note.

[14] Jean Buridan (circa 1300–circa 1360), a famous scholastic doctor,
who was several times rector of the university of Paris and
subsequently founded the university of Vienna. He forms the subject of
many legends, including that of the argument known by his name, of
which no trace is to be found in any of his works.—Translator’s Note.

[15] 3½ inches.—Translator’s Note.

[16] 3½ inches.—Translator’s Note.

[17] 4 feet 5 inches.—Translator’s Note.

[18] A large carnivorous Beetle.—Translator’s Note.

[19] The highest mountain in the neighbourhood of Sérignan. Cf. The
Hunting Wasps, by J. Henri Fabre, translated by Alexander Teixeira de
Mattos: chap. xi.—Translator’s Note.

[20] Geotrupes stercorarius, a large Dung-beetle. Cf. The Life and Love
of the Insect, by J. Henri Fabre, translated by Alexander Teixeira de
Mattos: chap. ix.—Translator’s Note.

[21] .975 by .351 inch.—Translator’s Note.

[22] Cf. The Hunting Wasps: chaps. xiv to xvii.—Translator’s Note.

[23] A Bacon-beetle.—Translator’s Note.

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

[25] Psyche unicolor, Hufn.; P. graminella, Schiffermüller.—Author’s
Note.

[26] As far as can be judged from the case only, Psyche febretta, Boyer
de Fonscolombe.—Author’s Note.

[27] Fumea comitella and F. intermediella, Bruand.—Author’s Note.

[28] A fictitious character, a sort of dolt, created by some wit in a
French regiment quartered in Brabant about the year 1792. Cadet
Roussel’s entertaining exploits were perpetuated in a contemporary
ballad.—Translator’s Note.

[29] Cf. Chapter XI. of the present volume.—Translator’s Note.

[30] For other instances of what Fabre calls “the insect’s mental
incapacity in the presence of the accidental” I would refer the reader
to one essay inter alia, entitled, Some Reflections upon Insect
Psychology, which forms chap. vii. of The Mason-bees.—Translator’s
Note.

[31] Thursday is the weekly holiday in French schools.—Translator’s
Note.

[32] The Abbé Lazaro Spallanzani (1729–99), an early experimenter in
natural history and author of a number of important works on the
circulation of the blood, on digestion, on generation and on
microscopic animals. Cf. The Hunting Wasps: chap. xix.—Translator’s
Note.

[33] Cf. The Mason-Bees, passim.—Translator’s Note.

[34] Rabasso is the Provençal for truffle. Hence the word rabassier to
denote a truffle-hunter.—Author’s Note.

[35] For some account of Fabre’s drawings of the fungi of his district,
cf. The Life of the Fly, by J. Henri Fabre, translated by Alexander
Teixeira de Mattos: chap. xvii.—Translator’s Note.

[36] One of the Dung-beetles. Cf. The Life and Love of the Insect:
chap. v.—Translator’s Note.

[37] Cf. The Life of the Fly: chap. xviii.—Translator’s Note.

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

[39] A Dung-beetle. Cf. The Life and Love of the Insect: chap.
x.—Translator’s Note.

[40] 7.8 inches.—Translator’s Note.

[41] Since writing the above lines, I have found him eating one of the
true Tuberaceæ, Tuber Requienii, Tul., the size of a cherry.—Author’s
Note.

[42] Carrion-beetles proper.—Translator’s Note.

[43] Bacon-beetles—Translator’s Note.

[44] Burying-beetles proper.—Translator’s Note.

[45] A species of small carnivorous Beetles.—Translator’s Note.

[46] A species of Weevils found on thistle-heads.—Translator’s Note.

[47] .078 inch.—Translator’s Note.

[48] The author employs this word to denote the insects that are
helpful, while describing as “ravagers” the insects that are hurtful to
the farmer’s crops.—Translator’s Note.

[49] This order includes the Ichneumon-flies, of whom the Microgaster
is one.—Translator’s Note.

[50] .117 to .156 inch.—Translator’s Note.

[51] About 1¾ pints, or .22 gallon.—Translator’s Note.





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