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Title: Harvesting Ants and Trap-Door Spiders - Notes and Observations on Their Habits and Dwellings
Author: Moggridge, J. Traherne
Language: English
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SPIDERS ***
Transcriber's Note: Emphasis denoted as _Italics_.
Whole and fractional parts of numbers as 123-4/5.
_BY THE SAME AUTHOR._
Royal 8vo. In 4 parts, each, with 25 Coloured Plates,
15_s._, or complete in one vol. 63_s._
CONTRIBUTIONS TO THE FLORA OF MENTONE,
AND TO A
WINTER FLORA OF THE RIVIERA,
_Including the Coast from Marseilles to Genoa_.
BY
J. TRAHERNE MOGGRIDGE, F.L.S.
L. REEVE & CO., 5, HENRIETTA STREET, COVENT GARDEN.
HARVESTING ANTS
AND
TRAP-DOOR SPIDERS.
HARVESTING ANTS
AND
TRAP-DOOR SPIDERS.
NOTES AND OBSERVATIONS ON THEIR
Habits and Dwellings.
BY
J. TRAHERNE MOGGRIDGE, F.L.S.
[Illustration]
LONDON:
L. REEVE & CO., 5, HENRIETTA STREET, COVENT GARDEN.
1873.
LONDON:
SAVILL, EDWARDS AND CO., PRINTERS, CHANDOS STREET,
COVENT GARDEN.
CONTENTS.
PART I.
PAGE
HARVESTING ANTS 1
PART II.
TRAP-DOOR SPIDERS 71
EXPLANATION OF PLATES.
PART I.--HARVESTING ANTS.
Plate I., p. 21, fig. A.--View of the entrance to a nest of _Atta
barbara_, showing part of a train of ants bearing seeds, the
conical mound of refuse thrown out, and some seedlings, which
have sprung up from seeds accidentally dropped by the ants; B,
one of the larger workers of this species, of the natural size,
and B 1, its abdomen and pedicle, with two nodes, magnified; C*,
one of the smaller workers, of the natural size; C, a male, of
the natural size; D, a female, of the natural size; D 1, wing of
the same, magnified; D 2, mouth organs of the same, magnified,
with the mandibles removed, the two outer pieces being the
maxillæ and their palpi, and the lozenge-shaped piece the labium,
from the upper part of which the labial palpi spring, while
behind the labium is the true tongue; D 3, one of the mandibles,
magnified; E, a larva, of the natural size, and E 1, the same,
magnified.
Plate II., p. 22, fig. A.--A trowel containing earth, in which a
granary full of seeds is lying almost undisturbed, of the natural
size; B, the crater-like entrances found at the mouths of the
nests of _Atta structor_, reduced to one-half the natural size.
Plate III., p. 23.--The floors of three granaries of _Atta
barbara_, surrounded by the much coarser gravelly earth, of the
natural size.
Plate IV., p. 31.--A mass of earth pierced by roots, in which the
ants (_Atta barbara_) have made their granaries and galleries.
The galleries were full of seeds when first laid open. Of the
natural size.
Plate V., p. 33, fig. A.--Galleries and terminal cells of a nest of
_Atta barbara_, excavated in the living sandstone rock, drawn _in
situ_, of the natural size; B, part of a cylindrical gallery from
another rock-nest, and B 1, the same gallery seen in front, of
the natural size.
Plate VI., p. 35, fig. A.--A sprouting hemp-seed, part of the
radicle of which has been gnawed by the ants, of the natural
size; A 1, the same, magnified, _rad._ radicle; A 2, an entire
sprouting seed of the same, magnified; B, a sprouting pea, part
of the radicle of which has been gnawed off; B 1, the same,
magnified; B 2, the same stripped of its coat, and showing the
two seed leaves; C, a sprouting "canary-seed" (the grain of
_Phalaris canariensis_), part of the fibril of which has been
gnawed off; C 1, the same, magnified, _rad._ the radicle which
remains undeveloped, and _fib._ the fibril or first rootlet; C
2, an unmutilated sprouting "canary seed;" D, a mass of earth
taken out of the heart of a nest of _Atta barbara_, in which a
spherical cell, made of hardened earth, was buried. It contained
grass seeds, among which I found ants at work, and seeds of the
same grass still in their husks lay in the gallery leading up to
the entrance of this cell; D 1, the same, further freed from the
earth, and having part of one side removed, so as to show the
interior and the small lower opening leading out from the bottom
of the cell.
PART II.--TRAP-DOOR SPIDERS.
Plate VII., p. 88, fig. A.--The nest of _Cteniza fodiens_, the
lower part of which is seen in section lying in the earth, the
door is artificially represented as partly open; A 1, surface
of the door viewed from above; A 2, the spider; A 3, the spider
deprived of its legs, from a specimen preserved in spirits [figs.
A, A 1, A 2, and A 3, are of the natural size]; A 4, the spider
viewed sideways, with the legs removed; A 5, the eyes, viewed
from above and in front; A 6, the cephalothorax and falces; A 7,
the left hand falx, viewed from the inner side; A 8, the fang of
the same; A 9, the tarsal joint of the foremost right leg; A 10,
one of the two larger and the smallest claw of the same [figs.
A 4, 5, 6, 7, 8, 9, and 10, all magnified]. Fig. B, the door
of a nest of the same kind, concealed by lichens, below which,
on the left hand, the doors of two minute nests of _Nemesia
meridionalis_ are seen; B 1, the same, with the doors open; C,
the door and mouth of tube of a nest similar to that at A; C 1,
the upper surface of this door, which is slightly convex.
Plate VIII., p. 94, fig. A.--The nest of _Nemesia cæmentaria_;
A 1, the door of the same, partially open; A 2, the spider; A
3, the same deprived of its legs, from a specimen preserved in
spirits [figs. A, A 1, 2, and 3, of the natural size]; figs. A
4, 5, 6, 7, 8, 9, and 10 as in Plate VII., and magnified; B, a
moss-covered lump of earth, in which the door of a nest of the
same type as that at A lies concealed; B 1, the same, with the
door open; C, the door and mouth of another similar nest, showing
the claw marks on its under surface; D, the closed door of a
third nest of the same kind; D 1, the same, opened.
Plate IX., p. 98, fig. A.--The nest of _Nemesia meridionalis_; A
1, the open surface-door and mouth of the tube of the same; A 2,
the inner and upper surface of the lower door; A 3, the spider;
A 4, the same deprived of its legs, from a specimen preserved in
spirits [figs. A, A 1, 2, 3, and 4 are of the natural size]; A
5, the spider viewed sideways, with the legs removed; A 6, the
eyes, viewed from above and in front; A 7, the cephalothorax and
falces; A 8, the left hand falx viewed from the inner side; A
9, the fang of the same; A 10, the tarsal joint of the foremost
right leg; A 11, one of the two larger and the smallest claw of
the same [figs. A 5, 6, 7, 8, 9, 10, and 11, magnified]; B, a
mass of earth containing the minute nest of a young spider (_N.
meridionalis_); B 1, the lower door of this nest; B 2, the spider
[figs. B, B 1, and 2, of the natural size].
Plate X., p. 100, fig. A.--Part of a nest of _N. meridionalis_; B,
the new and larger upper door of a nest of this spider, with the
former and smaller upper door partially united to it; C, another
example of enlargement in the upper door of the same spider,
showing traces of two previous doors now incorporated. [All the
figures are of the natural size.]
Plate XI., p. 105, fig. A.--The upper part of a nest of _N.
meridionalis_ concealed in a plant of Ceterach fern; A 1 and A 2,
a minute cork-door, closed and open, which I saw constructed by a
very young spider [either _Cteniza fodiens_, or, more probably,
_Nemesia cæmentaria_] at the mouth of a hole in the mass of earth
containing the nest of _N. meridionalis_ figured at A. This hole
may be seen on the right of the fern. B, the door of a small nest
of _N. meridionalis_, as seen from above, in its natural position
in a steeply sloping bank; B 1, part of the same nest placed
in an upright position, and showing the surface door open and
the lower door closing the branch; B 2, the same with the lower
door pushed across so as to close the main tube; B 3, 4, and 5,
different views of this second door. [All the figures in this
plate are of the natural size.]
Plate XII., p. 106, fig. A.--The nest of _N. Eleanora_ with the
surface door artificially represented as being open; A 1, the
outer side of the surface door of the same nest into which mosses
of two kinds are woven; A 2, the second door of the same nest;
A 3, the spider; A 4, the same deprived of its legs, from a
specimen preserved in spirits [figs. A, A 1, 2, 3, and 4 are of
the natural size]; fig. A 5, the spider viewed sideways, with the
legs removed; A 6, the eyes viewed from above and in front; A
7, the cephalothorax and falces; A 8, the left-hand falx viewed
from the inner side; A 9, the fang of the same; A 10, the tarsal
joint of the foremost right leg; A 11, one of the two larger and
the smallest claw of the same [figs. A 5, 6, 7, 8, 9, 10, and 11,
magnified]; fig. B and B 1, the upper part of the tube and door
of a nest of _N. Eleanora_ which partially projected beyond the
surface of the earth and was clothed with living moss. [Figs. B
and B 1 are of the natural size.]
PART I.
HARVESTING ANTS.
PART I.
HARVESTING ANTS.
It was in May, 1869, that Mr. Bentham in his presidential address
to the Linnean Society called attention to the want of reliable
information as to the existence of such subterranean accumulations of
seeds as are popularly supposed to account for the sudden appearance
on railway cuttings, gravel from deep pits, and the like, of crops of
weeds hitherto unknown in a district.
He suggested that it might repay the trouble if some accurate
observers were to take this in hand, and investigate the matter
both by examining samples of undisturbed soil taken from various
depths,--when, if any seeds of moderate size were present and
undecomposed, it would be tolerably easy to distinguish them,--and
also by ascertaining what means of transport exist by which seeds may
be scattered over exposed surfaces, and thus explain the difficulty
without having recourse to hypothetical supplies of sound though
long-buried seeds.[1]
[Footnote 1: M. Kerner of Innspruck has lately adduced some facts
bearing on the question of the transport of seeds by the wind, having
examined the collections of animal and vegetable substances found
on the icy surfaces of glaciers and the plants growing on moraines.
Judging from the facts thus obtained, he attributes but a small
influence to this agency, as the specimens discovered belonged to
the fauna and flora of the immediate vicinity, and not one of these
specimens must needs have come from a distance. See abstract of his
paper in Gardener's Chronicle, Feb. 3, 1872, p. 143, and in 'Nature'
for June 27, 1872, p. 164.]
As I listened, the question occurred to me whether the ants, which
I had observed carrying seeds to their nests at Mentone, might not
be unconscious agents on a small scale, both in the distribution
and the subterranean storing of seeds. When at a later time I made
this suggestion to some of our leading naturalists, I learned with
considerable surprise that the unanimous opinion of our highest
modern authorities on the subject is opposed to the belief that
European ants ever do systematically collect and make provision
of seeds, and that the instances of such occurrences in tropical
climates remain as isolated though undoubted facts which it is
difficult to explain.
I was not then aware that towards the middle of last century the
ancient belief, dating from the time of Solomon, that ants habitually
show forethought and husbandry in the collection of supplies of seeds
and grain had begun to be called in question, and that our most able
observers, such as Huber, Gould, Kirby and Spence, and at the present
day Mr. Frederick Smith, had by close scrutiny of the habits of these
creatures proved that, wherever personal investigation had enabled
them to put the matter to proof, no trace of harvesting was found.[2]
[Footnote 2: I have myself on many occasions thrown seeds in the
track of the common English ants, and my experience was, up to the
past summer (1872), similar to that of the above-named naturalists,
but I have lately, by the merest chance, become acquainted with
a curious exception to this rule. It happened as follows. I was
gathering some fresh capsules of the common sweet violet in a garden
at Richmond, near London, and in pouring the seeds out of my hand
into the paper bag made to receive them, a few were spilled on the
ground. In a short time afterwards I was greatly surprised to see
some of these spilled seeds in motion, being carried by the common
black ant (_Formica nigra_) into its nest. On seeing this I hastened
to get some more fresh violet seeds, and also a quantity of seeds
taken from ant's granaries at Mentone, and scattered these where the
other seeds had lain. After watching for half an hour a few of the
violet seeds were carried in, but not one of the granary seeds was
removed, though these were examined with some curiosity. I repeated
this experiment twice afterwards on a distinct colony of ants of the
same kind and obtained exactly the same result. I opened the nest of
the former colony on the day after they had carried in the seeds, but
failed to find these or any stores of other seeds.
I am inclined to think that the ants took these seeds believing them
to be larvæ of other ants which they might eat; for fresh seeds
of violet are not very unlike the larvæ of certain ants, as, for
example, those of _Atta barbara_, figured at Plate I., Fig. E., p.
21, the semi-transparent membranous appendage partly concealing the
seed and giving it a fleshy appearance.
I think this the more likely because on two occasions the seeds which
had been carried into the nest were subsequently thrown out by the
ants, which had I believe discovered their mistake.]
However, just as the ancient writers, judging from their own
experience and from the reports of others, had erred in attributing
to ants in general the habit of seed-storing possessed by certain
species commonly found in the south, so have modern naturalists
fallen into the mistake of denying it to any of the European species.
The older authors who lived in Greece and Italy, and the mediæval
authors who drew their information in great measure from the former,
being familiar with the fact that some ants habitually collect large
supplies of seed, went so far as to assert, or to imply, that all
European ants do so; the authors of the present day, on the other
hand, generalizing too freely from their experience of ants found
near their northern homes, maintained and maintain the very reverse.
So long as Europe was taught natural history by southern writers the
belief prevailed; but no sooner did the tide begin to turn, and the
current of information to flow from north to south, than the story
became discredited.
It is interesting now to recall a few of the allusions to the
harvesting ants made by ancient authors, some of which contain
tolerably accurate accounts of what was to them a familiar sight or a
universally accepted fact.
The passages in Proverbs[3] are the following: "Go to the ant, thou
sluggard: consider her ways and be wise; which, having no guide,
overseer, or ruler, provideth her meat in the summer, and gathereth
her food in the harvest." "The ants are a people not strong, yet they
prepare their meat in the summer." Hesiod[4] speaks of the time
"When the provident one (the ant) harvests the grain."
ὅτἐ τ ιδρις σωρὀυ ἁμαται.
[Footnote 3: vi. 6-8 and xxx. 25.]
[Footnote 4: Works and Days, 776.]
Horace[5] also alludes to the foresight of the ant, who is "haud
ignara ac non incauta futuri." Virgil[6] compares the Trojans
hastening their departure to harvesting ants, and the passage has
been thus rendered by Dryden:--
"The beach is covered o'er
With Trojan bands, that blacken all the shore:
On every side are seen, descending down,
Thick swarms of soldiers, loaden from the town,
Thus, in battalia, march embodied ants,
Fearful of winter, and of future wants,
T' invade the corn, and to their cells convey
The plundered forage of their yellow prey.
The sable troops, along the narrow tracks,
Scarce bear the weighty burden on their backs;
Some set their shoulders to the ponderous grain;
Some guard the spoil; some lash the lagging train;
All ply their several tasks, and equal toil sustain."
[Footnote 5: Satires I. i. 33.]
[Footnote 6: Æneid, Bk. iv. l. 402.
"Ac velut ingentem formicæ farris acervum
Quum populant, hiemis memores, tectoque reponunt:
It nigrum campis agmen, prædamque per herbas
Convectant calle angusto; pars grandia trudunt
Obnixæ frumenta humeris; pars agmina cogunt,
Castigantque moras; opere omnis semita fervet."
]
Indeed, it would seem that among the people inhabiting the shores
of the Mediterranean it was almost as common to say "as provident
as an ant" as it is with us to say "as busy as a bee." Plautus[7]
introduces a slave who, when attempting to account for the rapid
disappearance of a sum of money of which he had charge, says,
"Confit cito
Quam si tu objicias formicis papaverem."
"It vanished in a twinkling,
Just like poppy seed thrown to the ants."
[Footnote 7: Trinummus, Act ii. sc. 4, l. 7.]
Any one who has seen the eagerness with which certain southern ants
seize upon seeds thrown in their path will appreciate the correctness
of this simile.
Claudius Ælianus, who lived in the time of Hadrian, gives a detailed
account of the habits which he attributes to ants,[8] from which the
following is a translation: "In summer time, after harvest, while
the ears are being threshed the ants pry about in troops around the
threshing floors, leaving their homes, and going singly, in pairs, or
sometimes three together. They then select grains of wheat or barley,
and go straight home by the way they came. Some go to collect, others
to carry away the burden, and they avoid the way for one another with
great politeness and consideration, especially the unburdened for
the weight carriers. Now these excellent creatures, when they have
returned home, and stored their granaries with wheat and barley, bore
through each grain of seed in the middle; that which falls off in the
process becomes a meal for the ants, and the remainder is unfertile.
This these worthy housekeepers do, lest when the rains come the seeds
should sprout, as they would do if left entire, and thus the ants
should come to want. So we see that the ants have good share in the
gifts of nature, in this respect as well as others." Further on[9]
he gives a very interesting account of their mode of collecting and
preparing the grain, many details of which I can myself substantiate
from personal observation, though I have never seen ants actually
at work upon the ears of corn. "But when the ants start a foraging,
they follow the biggest, who take the lead as generals. And when
they come to the crops, the younger ones stand under the stalk, but
the leaders ascending gnaw through the culms, as they are called
[ὀυραγοὑς, 'the stalk ends on which the ears grow' (Lid. and Scott,
Gr. Lex.)], probably meaning that they detach the separate spikelets
of which the ears are composed], of the ears [καρπἱμων], which they
throw to the people below. These busy themselves with cutting away
the chaff and peeling off the envelopes which contain and cover the
grain. So the ants, though they need no threshing time, nor men to
winnow for them, nor an artificial draught of wind to separate corn
and chaff, yet have the food of men who both plough and sow for it."
Ælian appears also to have heard reports of the habits of ants in
tropical countries, for he says,[10] "Certainly the Indian ant is
also a wise creature.... They leave one opening at the top (of the
nest), by which they have their exits and entrances, when they come
bearing the seeds which they collect." I have never myself found
seeds bored through the centre in the way recorded above, but it is
possible that different species of ants may treat the seeds in other
ways than those observed by me; or, on the other hand, Ælian may have
mistaken the gnawing off the radicle of the seed, a process which I
shall describe from personal observation below, and imagined that the
seed itself was pierced.
[Footnote 8: Ælian, De Naturâ Animalium, ii. 25.]
[Footnote 9: Ælian, De Nat. Anim., lib. vi. chap. xliii.]
[Footnote 10: Id. lib. xvi. 15.]
Aldrovandus, writing in the sixteenth century, speaks[11] of the ants
as storing seed and of their gnawing, "illud principium seu acumen
grani, è quo germen emitti à tritico solet"--that is to say, the
radicle. But it is not clear whether Aldrovandus treats of what he
has himself seen or refers to the account given by a certain Bishop,
Simon Mariolus, who, he says "in his most pleasant and learned work,
introduces a philosopher as taking his walks abroad and examining an
ant's nest with its seed store," &c.
[Footnote 11: Aldrovandus, De Insectis, lib. v. (de Formicis).]
The lively fable of the ant and the grasshopper, as related by La
Fontaine, has done much towards familiarizing and keeping alive in
the minds of many of us the idea that ants habitually provide stores
against the winter; but we must not infer from this narration that
the witty French author had ever cared to examine for himself whether
the fable, which he borrowed from Æsop, had its foundation in fact or
not. The following translation from, the Greek original[12] bears in
a much higher degree the impress of personal and accurate observation.
[Footnote 12: For this translation and all the foregoing extracts
from ancient and mediæval authors I have to thank my brother, M. W.
Moggridge.]
Μὑρμηκες καἰ Τἑττιξ: The Ants and the Grasshopper. Once in winter
time the ants were sunning their seed-store which had been soaked
by the rains. A grasshopper saw them at this, and being famished
and ready to perish, he ran up and begged for a bit. To the ant's
question, "What were you doing in summer, idling, that you have
to beg now?" he answered, "I lived for pleasure then, piping and
pleasing travellers." "O, ho!" said they, with a grin, "dance in
winter, if you pipe in summer. Store seed for the future when you
can, and never mind playing and pleasing travellers."[13] It would
be easy to multiply instances in which the older authors allude to
this habit, but enough have been given to afford a sample of what
may easily be found repeated elsewhere, and I will now quote a few
instances which illustrate the more modern belief, utterly opposed to
that so long maintained by the ancients.
[Footnote 13: Æsopicæ Fabulæ (Tauchnitz edition), p. 92.]
Messrs. Kirby and Spence[14] discuss the matter in the following
terms:--"When we find the writers of all nations and ages unite in
affirming that, having deprived it of the power of vegetating, ants
store up grain in their nests, we feel disposed to give larger credit
to their assertions. Writers in general have taken ... (this) ... for
granted. But when observers of nature began to examine the manners
and economy of these creatures more narrowly, it was found, at least
with respect to the European species of ants, that no such hoards of
grain were made by them; and, in fact, that they had no magazines in
their nests in which provisions of any kinds were stored up."
[Footnote 14: Entomology, ed. 7 (1856), p. 313.]
They then proceed to explain how easily the white pupæ, which the
ants carry about in their jaws, may have been mistaken for grains of
wheat, and to inform us that the accurate observations of Mr. Gould,
published in 1747, were among the first which led to the correction
of this error. "However," they continue, "it may be otherwise with
exotic ants, for although during the cold of our winters they are
generally torpid and need scarcely any food, yet in warmer regions,
during the rainy seasons, when they are probably confined to their
nests, a store of provisions may be necessary for them."
The author of the article on ants in Smith's Dictionary of the Bible
says, in reference to the assertion that ants store seed, that
"observation of the habits of ants does not confirm this belief."
Latreille[15] denies it in the following emphatic terms:
"N'attribuons pas à la fourmi une prévoyance inutile: engourdie
pendant l'hiver, pourquoi formeroit elle des greniers pour cette
saison?"
[Footnote 15: Hist. Nat. des Fourmis, 1802.]
Huber again throws the weight of his great authority into the scale
against the ants, when he says,[16] "I am naturally led to speak in
this place of the manner in which ants subsist in the winter, since
we have relinquished the opinion that they amass wheat and other
grain, and that they gnaw the corn to prevent it from germinating."
He then goes on to show how the ants are frequently torpid during the
winter, and that when it happens that a few warmer days wake them up
to life, they can always find a few aphides also on the alert; for,
strange to say, the same degree of warmth which rouses the ants calls
forth the aphides also. It would appear that ants in the northern
parts of Europe feed on the honey-dew of aphides, and on animal
matter when they can get it; and up to the present time the belief
prevails among our modern naturalists that they are limited to the
same diet in all parts of Europe.
[Footnote 16: Huber, on Ants, translated by J. R. Johnson, 1820.]
It is now well known, however, that exceptions must probably be made
in tropical countries, for the observations of Lieut.-Col. Sykes[17]
and Dr. Jerdon[18] have shown that many ants in India collect grain
in large quantities, robbing the crops and plants cultivated in
gardens, and even stealing seeds put away in drawers, the inference
being that they employ them for food. The same observers have
recorded how the ants may be seen after wet weather bringing out the
grain to dry in the sun.
[Footnote 17: Lieut.-Col. Sykes, Description of New Indian Ants, in
Trans. Ent. Soc. Lond., i. 103 (1836), where a single species of
ant, which he names _Atta providens_, is described, and its habit of
harvesting recorded.]
[Footnote 18: Dr. Jerdon, Madras Journal Lit. and Sc. (1851), where
three species are stated to harvest seeds on a large scale--namely,
_Œcodoma (or Atta) providens_, _Œcodoma diffusa_, and _Atta rufa_,
all of which belong to the same section of ants as our Mentonese
harvesters, _Atta barbara_, _Atta structor_, and _Pheidole (or Atta)
megacephala_. These very interesting observations of Dr. Jerdon's, as
well as those of Lieut.-Col. Sykes, will be found in Appendix B.]
Dr. Lincecum has also given a very interesting account[19] of the
habits of the "agricultural ant" inhabiting Texas, _Myrmica (Atta)
barbata_, which not only stores the grain of a particular rice-like
grass, but is said to maintain a clean crop of this plant around its
nest, suffering no weed to appear among it, and harvesting the crop
in its proper season.
[Footnote 19: Published in the Journal of the Linnean Society of
London, vol. vi. p. 29. 1861.]
The Sauba ant (_Œcodoma cephalotes_) has been seen by Mr. Bates
plundering baskets containing mandioca meal (an impure form of
tapioca) in Brazil, and this in so wholesale a manner as shortly to
threaten the loss of the entire supply; and Dr. Delacoux records[20]
the presence in New Granada of a monstrous ant, called by the natives
_Arieros_, a word which, I am informed, is of Arabic extraction, and
means the _carrier_, which emptied an entire sack of maize belonging
to him in a single night.
[Footnote 20: Notice sur les Mœurs et les Habitudes de quelques
Espèces de Formiciens des Climats Chauds. Rev. Zool., Mai, 1848, p.
1849.]
It seems strange that while travellers have reported the seed-storing
habits of ants in far distant countries, our naturalists at home
should have not only remained unaware of its existence in Europe, but
even strenuously denied it. It is certain, however, that naturalists
and others in southern Europe are more or less aware of the fact, but
I have been unable to learn that any accurate account of the habits
of harvesting ants has hitherto been published, or that any one has
taken pains to discover what becomes of the seed so laboriously
obtained.
It is true that in the _Enciclopedia Popolare_[21] extracts are
given from the remarks made by M. Gené[22] on the subject, in which
he assumes that the fact that ants collect and carry to their nest
large supplies of grain and seed is well known, but states that he is
at a loss to conceive how they employ them, unless it may be that
they use them as materials for the construction of their galleries,
for they cannot eat such hard substances, all their food being
either liquid or of the nature of juices, "gli alimenti sono sempre
materie liquide o materie sugose. Quanto ai corpi duri e secchi che
le formiche raccolgono, io non so altrimenti riguardarli che come
materiali di costruzione." It will be understood, I think, from what
has gone before, that thus far nothing has really been ascertained as
to the exact state of the case; for though the Italian author just
quoted was aware that certain ants in the Mediterranean region do
store seed, his knowledge went no further. Nor am I aware that any
French author has published an account of this habit and its object;
and in a recent abundantly illustrated volume founded on a work by
M. Emile Blanchard, I find, on the contrary, the following very
emphatic denial of its existence:--"The curious idea which appears
to have commenced in very remote times, and to have been carried
down by tradition, and which was assisted by the results of careless
observations, concerning the habits of the ants in collecting and
storing up provisions, as it were under the influence of a wise
foresight, is evidently incorrect."[23] There was, therefore, clearly
an opening here for close observation, and this I determined to do my
best to supply.
[Footnote 21: Article Formica, vol. v. p. 143-4. (Turin, 1845).]
[Footnote 22: Memorie per servire alla Storia Naturale di alcuni
imenotteri, published at Modena, in 1842.]
[Footnote 23: The Transformations of Insects: an adaptation for
English readers of M. Emile Blanchard's Metamorphoses, Mœurs, et
Instincts des Insectes, p. 196. London. 1871.]
When I set out again from England in October, 1871, on my way to
Mentone, I had obtained an idea of some of the leading points which
needed to be cleared up, and I was greatly encouraged in my attempt
by the interest expressed in the subject by several of our leading
naturalists, among whom I may especially mention Mr. Frederick
Smith.[24]
[Footnote 24: am very greatly indebted to Mr. Smith for much kind
assistance, and especially for having named the specimens which I
collected.]
Plainly the first thing to do was to determine whether the seeds
which I had watched the ants carry to their nests were separately
stored in subterranean granaries, as they would be if the ant really
provides for the future; or whether they were merely strewed here and
there, or used as building materials.
Next I must, if possible, obtain conclusive evidence as to the use to
which the ants put the seeds thus collected; whether they eat them
or turn them to some other account. Again I must observe whether
the seed-collecting ants also search for aphides, and what other
kinds of food they obtain. Then another very interesting question
remained--namely, whether all southern ants uniformly collect seed,
and to the same extent, or whether the habit is peculiar to certain
species.
These, and many other subjects of inquiry connected with them,
readily suggested themselves to my mind, and it will now be my
endeavour to show how far I have been able to throw light upon them.
The habits recorded in the following pages refer exclusively, unless
special notice is given to the contrary, to _Atta barbara_, the
black ant represented on Plate I. We have, as far as I am aware,
only four _bonâ fide_ harvesting ants on the Riviera--namely, _Atta
barbara_ under two forms, the one wholly black the other red-headed;
_Atta structor_, a creature very similar to _barbara_, but of a
claret-brown colour; and a minute yellow ant, the large workers of
which have gigantic heads, named _Pheidole_ (or _Atta_) _megacephala_.
My renewed observations at Mentone were carried on from October,
1871, to May, 1872, and I was able during that interval to become a
frequent visitor to a warm and sheltered valley, which lay but a few
minutes' walk from the house in which I lived, and in which thirty
nests of the most active of the seed-storing ants were to be found.
Full therefore of my intention to resolve this difficulty if
possible, I set out on October 29, 1871, immediately after my return
to Mentone, to revisit this valley, where, in the previous May, I had
seen the ants busily engaged in cutting, carrying, and sorting their
harvest.
The spot in question was a rough slope of soft sandstone rock, with
accumulations of sandy soil in the hollows, covered with a sparse and
scrubby vegetation, composed of _Cistus_ (_C. salvifolius_), pot-herb
thyme, black lavender (_Lavandula stæchas_), spiny broom (_Calycotome
spinosa_), overshadowed here and there by a few scattered stone and
maritime pines, and intermixed with coarse grasses and some smaller
plants.
Cultivated lemon terraces lay on the edge of the wild ground lower
down in the valley, and at this season, as also in the late spring,
these terraces were overgrown with a rank crop of weeds, most of
which were in seed.
I had scarcely set foot on the _garrigue_, as this kind of wild
ground is called, to distinguish it from meadows or terraced land,
before I was met by a long train of ants, forming two continuous
lines, hurrying in opposite directions, the one with their mouths
full, the others with their mouths empty.
It was easy enough to find the nest to which these ants belonged, for
it was only necessary to follow the line of ants burdened with seeds,
grain, or entire capsules, which had their heads turned homewards,
and there, sure enough, at about ten yards distance, and partly
shaded by some small _Cistus_ bushes, lay the nest, to and from the
entrances of which the incessant stream of incomers and outgoers kept
flowing.
The proceedings of the ants were the same as those previously
observed in the late spring (April and May), the workers usually
seeking their harvest at some distance from the nest, and going in
search of it as far as the cultivated ground, where the crops of
weeds were more abundant and more varied.
In a few cases, however, where the terraces were too far distant,
they contented themselves with plundering the grasses, pea-flowers,
honeywort, and the other denizens of the garrigue. In one case I was
able to follow the thread-like column of workers from the nest to the
weedy terrace where the plants grew from which they were gathering
the seeds, and found that the nearly continuous double line measured
twenty-four yards. Even this gives but an inadequate idea of the
number of ants actively employed in the service of this colony, for
hundreds of them were dispersed among the weeds on the terrace, and
many were also employed in sorting the materials and in attending to
the internal economy of the nest. Still this affords some evidence
of the systematic and extensive scale on which foraging is carried on
by this ant, and of the high importance which these creatures attach
to their provision of grain.
It is not a little surprising to see that the ants bring in not
only seeds of large size and fallen grain, but also green capsules,
the torn stalks of which show that they have been freshly gathered
from the plant. The manner in which they accomplish this feat
is as follows. An ant ascends the stem of a fruiting plant, of
Shepherd's-purse (_Capsella Bursa pastoris_) let us say, and
selects a well-filled but green pod about midway up the stem, those
below being ready to shed their seeds at a touch. Then, seizing
it in its jaws, and fixing its hind legs firmly as a pivot, it
contrives to turn round and round, and so strain the fibres of the
fruit-stalk that at length they snap. It then descends the stem,
patiently backing and turning upwards again as often as the clumsy
and disproportionate burden becomes wedged between the thickly set
stalks, and joins the line of its companions on their way to the
nest. In this manner capsules of chickweed (_Alsine media_) and
entire calyces, containing the nutlets of Calaminth, are gathered;
two ants also sometimes combine their efforts, when one stations
itself near the base of the peduncle and gnaws it at the point of
greatest tension, while the other hauls upon and twists it. I have
never seen a capsule severed from its stalk by cutting alone, and
the mandibles of this ant are perhaps incompetent to perform such a
task. I have occasionally seen ants engaged in cutting the capsules
of certain plants drop them and allow their companions below to carry
them away; and this corresponds with the curious account given by
Ælian[25] of the manner in which the spikelets of corn are severed
and thrown down "to the people below," [Greek: tô dêmô tô katô] τω
δἡμω κἁτω.
[Footnote 25: Vide supra, p. 8.]
If the incoming and weight-carrying column of ants be closely
examined it will be found that though the great majority of workers
are bringing seeds in some form to the nest, a few are burdened with
other and more miscellaneous materials.
Occasionally one or two may be detected carrying a dead insect, or
crushed land-shell, the corolla of a flower, a fragment of stick, or
leaf, but I have never seen aphides brought in to the nest or visited
by this ant or by _Atta structor_.
It sometimes happens that an ant has manifestly made a bad selection,
and is told on its return that what it has brought home with much
pains is no better than rubbish, and is hustled out of the nest,
and forced to throw its burden away. In order to try whether these
creatures were not fallible like other mortals, I one day took out
with me a little packet of grey and white porcelain beads, and
scattered these in the path of a harvesting train. They had scarcely
lain a minute on the earth before one of the largest workers seized
upon a bead, and with some difficulty clipped it with its mandibles
and trotted back at a great pace to the nest. I waited for a little
while, my attention being divided between the other ants who were
vainly endeavouring to remove the beads, and the entrance down which
the worker had disappeared, and then left the spot. On my return
in an hour's time, I found the ants passing unconcernedly by and
over the beads which lay where I had strewn them in apparently
undiminished quantities; and I conclude from this that they had
found out their mistake, and had wisely returned to their accustomed
occupations.
I have often amused myself by strewing hemp and canary seed or oats,
all of which form heavy burdens for the ants, near their nests;
and it is a curious sight to watch the eagerness and determination
with which they will drag them away. It is interesting also to note
how on the following day the husks of these seeds will appear on
the rubbish-heap, or sometimes, after a shower of rain, they will
be brought out by the ants with the point of the little root (the
radicle or fibril as the case may be) gnawed off (see Figs. A, B, C,
Plate VI., p. 35).
It frequently happens that on the wild hillside the position of a
nest of _Atta barbara_ is indicated by the presence of a number
of plants growing on or round the kitchen midden, which are
properly weeds of cultivation, and strangers to the cistus- and
lavender-covered banks of the garrigue. These have sprung from
seeds accidentally dropped by the ants, and which they had obtained
from the lemon terraces. Thus when you see little patches of ground
from one to three feet long and broad, covered with such plants as
fumitory (_Fumaria_), oats (_Avena_), nettles (_Urtica membranacea_),
four species of _Veronica_, chickweed (_Alsine media_), goosefoot
(_Chenopodium_), _Rumex Bucephalephorus_, wild marigold (_Calendula
arvensis_), _Antirrhinum Orontium_, _Linaria simplex_, and _Cardamine
hirsuta_, you may confidently expect to find a colony of these ants
close at hand.
[Illustration: _Plate I._]
These plants are sometimes found along the sides of miniature
gullies and crevices in the rock, where they have been washed by
little runlets of water formed in seasons of heavy rain, and thus
these interloping plants are occasionally dispersed and brought into
competition with the rightful occupiers of the ground.
_Atta structor_ and _A. barbara_ do not employ any materials in the
construction of their nest, simply excavating it out of the earth
itself, or occasionally out of the sandy rock, and the large mounds,
in great part composed of vegetable matter, which may frequently
be found at the entrances of their nests, are nothing more than
the rubbish heaps and kitchen middens of each establishment. These
consist in part of the earth pellets and grains of gravel which
the ants bring out from their nest when forming the subterranean
galleries, but principally of plant-refuse such as the chaff of
grasses, empty capsules, gnawed seed-coats, and the like, which
would occupy much space if left inside the nest (see Plate I., Fig.
A.). While an army of workers are employed in seeking and bringing
in supplies, others are busy sorting the materials thus obtained,
stripping off all the useless envelopes of seed or grain, and
carrying them out to throw away. Thanks to the unwearied activity
with which this divided labour is carried on the kitchen middens
speedily rise in the harvest season, and in places where they are not
exposed to the action of wind and rain, often acquire a considerable
size, so much so that sometimes, if collected, one alone might fill a
quart tankard.
It was the sight of such a refuse mound, and an examination of the
materials which composed it,--many of which show that they were
once parts of seeds, &c., the albuminous contents of which had
been extracted through holes gnawed in the side,--that gave me the
conviction that large stores of seed must lie hidden below in the
nest; for if it were true, as some have suggested, that the ants
employ the grain and seeds which they collect as materials for the
construction of their nest, they would certainly not reject such
parts as the chaff of grasses and the like, which are admirably
suited for the purpose, and are actually used for this end by other
species of ants.
It was therefore with the greatest confidence as to the result that I
opened the nests of _Atta barbara_ in search of granaries and seeds.
My first attempt was made upon a nest lying in a hollow where there
was a rather deep bed of soil, and the galleries extended so far on
either side and in a downward direction that, though I removed enough
soil to fill a wheelbarrow, I failed to reach the arcana of the nest,
and saw neither chambers nor granaries.
Yet I frequently encountered workers carrying seeds downwards along
the subterranean passages. I then selected a nest where the coarse
and hard rock lay much nearer to the surface, barring their downward
course, and compelling the ants to extend their nest in a horizontal
direction.
Here, almost at the first stroke, I came upon large masses of seeds
carefully stored in chambers prepared in the soil. Some of these
lay in long subcylindrical galleries, and, owing to the presence in
large quantities of the black shining seeds of amaranth (_Amaranthus
Blitum_, &c.), looked like trains of gunpowder laid ready for
blasting. Fig. A, Plate II. represents a trowelful of earth taken
from this nest, and lifted with care so as to leave the seeds almost
_in situ_. Others were massed together in horizontal chambers, having
a concave roof and a flat and carefully prepared floor.
[Illustration: _Plate II._]
[Illustration: _Plate III._]
The texture of the floor usually differs markedly from that of the
surrounding soil, and the fine grains of silex and mica which are
selected for its construction are more or less cemented together, so
that the floor will sometimes part, when dry, from the soil about it,
as caked and dry mud separates from a gravel path (see Plate III.).
On carefully examining a quantity of the seeds, grain, and minute
dry fruits taken from the granaries, I found that they had been
gathered from the following plants: fumitory (_Fumaria Capreolata_,
&c.), amaranth (_Amaranthus Blitum_, &c.), _Setaria_, and three other
species of grasses, honeywort (_Alyssum maritimum_), _Veronica_, and
from four unrecognised species, one of which was a pea-flower. There
were therefore in this nest seeds, &c., which had been taken from
more than twelve distinct species of plants, belonging to at least
seven separate families. The granaries lay from an inch and a half to
six inches below the surface and were all horizontal. They were of
various sizes and shapes, the average granary being about as large as
a gentleman's gold watch.
I was greatly surprised to find that the seeds, though quite moist,
showed no trace of germination, and this was the more astonishing as
the self-sown seeds of the same kinds as those detected here, such
as fumitory for instance, were then coming up abundantly in gardens
and on terraces. The seeds of _Odontites lutea_ afford a curious test
of the presence of moisture in the granaries, and it will usually
be found that, when they are recently taken out of the nest, they
are of a greenish colour and semi-transparent horn-like texture,
which changes on exposure to the air to a chalky white and opaque
appearance, due to the drying of the coat of the seed.
The fact of the sound condition of the seeds in these granaries
seemed to me so very strange and difficult to explain that I
determined to pay special attention to the subject, and with this
view collected and carefully examined large quantities of the grain
and seeds taken at different times from the stores of twenty-one
distinct nests, the first of which was opened on October 29th, and
the last on May 5th. In these twenty-one nests out of the thousands
of seeds taken I only found twenty-seven in seven nests which showed
trace of germination, and of these eleven had been mutilated in such
a way as to arrest their growth. The sprouting seeds were found in
the months from November to February, while in the nests opened in
October, March, April, and May, no sprouted seeds were discovered,
though these latter months are certainly highly favourable to
germination. It is therefore extremely rare to find other than sound
and intact seeds in the granaries, and we must conclude that the ants
exercise some mysterious power over them which checks the tendency to
germinate.
Apparently it is not that moisture or warmth or the influence of
atmospheric air is denied to the seeds, for we find them in damp
soil, in genial weather, and often at but a trifling distance below
the surface of the ground; and I have proved that the vitality of
the seeds is not affected by raising crops of young plants, such as
fumitory, pellitory, _Polygonum aviculare_, and grasses, from seeds
taken out of granaries.[26]
[Footnote 26: This experiment was tried by me on two occasions,
in the former case the seeds were taken from a granary about four
inches below the surface of the ground, on November 10th, and sowed
two days afterwards, and several of these were up on Dec. 1st. The
second trial was made on seeds found at only one and a half inch
below the surface, on Dec. 29th, 1871; these were sowed in England on
June 18th, 1872, and the young plants made their appearance in large
numbers ten days afterwards.]
I have frequently remarked that it is the seeds last collected before
a fall of rain which are brought out in a sprouting condition from
the nest; for I have observed in cases where I had recently scattered
seeds near wild nests, that it is these which are carried out from
the nest and placed to dry after a wet night; and so in the case of a
nest which I kept in captivity, when a variety of different seeds had
been successively supplied to the ants, it was the cabbage, lettuce,
and chicory seeds, given the day before the nest was watered, that
reappeared after having been carried below, and not the hemp, canary,
and mixed seeds of wild plants previously strewed on the nest. It
seems possible that the process, whatever it may be, to which the
ants subject the seeds which are to remain dormant may require some
time, and the construction of the granary chambers is doubtless a
long affair, so that when unusually large supplies of grain, &c.,
are brought in by the workers some part of them may not find the
necessary accommodation and attention. When the seeds do germinate
in the nests, and it is my belief that they are usually softened
and made to sprout before they are consumed by the ants, it is very
curious to see how the growth is checked in its earliest stage,
and how, after the radicle or fibril--the first growing root of
dicotyledonous and monocotyledonous seeds--has been gnawed off, they
are brought out from the nest and placed in the sun to dry, and then,
after a sufficient exposure, carried below into the nest.
The seeds are thus in effect malted, the starch being changed into
sugar, and I have myself witnessed the avidity with which the
contents of seeds thus treated are devoured by the ants.
Figs. A, B, C, in Plate VI., p. 35, illustrate the manner in which
the ants mutilate the germinating seeds and check their growth.
Thus, at Fig. C 2 of Plate VI. a sprouting but uninjured canary seed
(_Phalaris canariensis_) is drawn, magnified, and at Figs. C and C
1 the same of the natural size and magnified, after the ants have
gnawed its fibril (fib.), which in this case pierces the undeveloped
radicle (rad.). Fig. A 2 represents a sprouting hemp-seed,
magnified,[27] and Figs. A, A 1, the same of the natural size and
magnified, mutilated, the tip of the radicle being removed.
[Footnote 27: Properly a nut, for it comprises the seed and the
enveloping coat of the ovary. The canary seed also, spoken of above,
is a grain containing a seed.]
At Figs. B, B 1, B 2, the same process is shown in the case of a
small wild pea.
It is, however, certain that though a few individual seeds may sprout
in the nests from time to time either with or without the concurrence
of the ants, the great mass remain for many weeks, or even months,
quite intact, neither decaying nor germinating, whereas every one
knows that if a quantity of seeds are placed in the soil in a moist
and warm place, all the seeds that are of one kind will almost
simultaneously begin to grow after the lapse of a fixed interval.
Now if this took place in an ant's nest, the provisions would
have to be rapidly consumed at stated periods and to be frequently
renewed; but this is not the case. This is easily shown by an
examination of the seeds contained in the nests in April or May, many
of which will prove to belong to plants which fruit in the autumn and
are not to be found later than November. Thus, for example, on May
5th at Cannes, I discovered nutlets of _Cynoglossum pictum_, which
can scarcely have been collected later than the preceding October
or November. Besides, during the time from the middle of January to
the middle of March, scarcely a seed is collected under ordinary
circumstances, there being extremely few wild plants in fruit at that
season, and yet the granaries will be found well filled if a nest is
opened at the end of this period.
A knowledge of the fact that ants in warm climates accumulate large
and very varied stores of seeds retaining their power of germination,
might at times be of service to travellers, by enabling them to
obtain, by a stroke or two of the spade, an interesting collection
of the seeds and the seed-like fruits of the country, when time
and opportunity failed for obtaining them in a more satisfactory
manner. The following list of plants, the grain, seeds, and small dry
fruits of which I have found in the subterranean granaries of _Atta
structor_ and _A. barbara_, especially the latter, shows that the
ants probably collect almost indiscriminately from any fruiting plant
that falls in their way.
Fumitory (_Fumaria_, three species), honeywort (_Alyssum maritimum_),
narrow-leaved sun rose (_Fumaria viscida_ and _F. Spachii_),
_Oxalis corniculata_, _Silene_, _Linum gallicum_, mallow (_Lavatera
cretica_?), medick (_Medicago_), wild lentil (_Ervum_), spiny
broom (_Cytisus spinosus_), _Valerianella carinata_, _Centaurea
aspera_, _Odontites lutea_, _Calamintha Nepeta_, _Polygonum
convolvulus_ and _P. aviculare_, amaranth (_Amaranthus Blitum_ and
_patulus_), pellitory (_Parietaria_), _Euphorbia_, pine (_Pinus_),
wild sarsaparilla (_Smilax aspera_), _Setaria verticillata_ and
_S. italica_, _Andropogon Ischæmum_, and of eight other plants of
which I do not recognise the seeds. This list, comprising plants
belonging to eighteen distinct families, might be greatly prolonged
if I were to add to it the names of the seeds which I have seen the
ants carry towards their nests, but have not actually detected in
the granaries. Thus I have seen trains of ants burdened with the
long-beaked, spirally-twisted fruits of crane's bill (_Erodium_),
and, as above mentioned, with capsules of chickweed (_Alsine media_)
and shepherd's-purse (_Capsella Bursa pastoris_), with whole orange
pips, and even haricot beans, seeds of the New Zealand veronica
(_V. Andersonii_), of _Silene pseudoatocion_, and many other garden
plants, also with nutlets of the plane tree and seeds of the cypress.
Pliny mentions[28] incidentally having watched the ants carrying away
cypress seeds, and comments upon the fact that so small a creature
should be able to interfere with the growth of such a noble tree.
[Footnote 28: Pliny, Nat. Hist., xvii. 14, 3.]
I have little doubt that the seed stores of the ants in botanic and
other gardens, where rare plants are cultivated in southern Europe
and in warm climates generally, contain samples taken from the fruits
of a great many of the rarer and more interesting species as well as
of the weeds and native plants. Indeed I have been told that this is
the case by my friend Dr. Bornet, who complains of the depredations
committed by the ants in the gardens of the Villa Thuret, at Antibes.
They go so far as to plunder the seed bags which are hung from the
branches of the trees and shrubs, unless these are securely closed
and tied with string; they carry off wholesale the grass and anemone
seeds,[29] which are scattered when the lawns are resown; and Dr.
Bornet has seen the seeds of _Acacia retinoides_ lie heaped up by the
handful at the entrances of their nests, and disappear below after a
few hours.
[Footnote 29: Properly grass grain and anemone achenes.]
M. Germain de St. Pierre has observed similar facts at Hyères, where
he has detected large stores of cereals in the granaries of the ants,
and considers that the robberies committed by these creatures are
sufficient in extent to cause a serious loss to cultivators.
It is difficult to estimate the amount of seed stored in a single
nest by a colony of ants both on account of the extent of these
nests, and because of the number of seeds which are always lost in
digging. The nests themselves also vary greatly in size. Perhaps I
shall not be very far from the mark however, if I conjecture that
average-sized nests contain during the winter months about half a
pint of seeds.
_Atta structor_ is more frequently found near houses and in gardens
than _A. barbara_, the latter usually living on wild ground adjoining
cultivation. There was a flourishing colony of _structor_ in the main
street of Mentone, cleverly placed at the lintel of the door of a
corn chandler's store, where they were ever on the look out for stray
grains of oats and wheat, which might chance to fall from the sacks.
Another nest, in a different part of the town, got its principal
subsistence from the grains of canary seed, which were scattered by
the birds occupying a cage hanging outside a shop window at a little
distance.
[Illustration: Vertical section of an ant's nest. The horizontal
lines represent inches of depth.]
The granaries of _A. structor_ are arranged in the same way as those
of _A. barbara_, and may, in like manner, be found stored with seeds,
and lying at depths below the surface, varying from one to twenty
inches.
[Illustration: Plate IV.]
A diagram is given in the preceding woodcut of a vertical section of
a nest of _barbara_ lying in soil sixteen inches deep, the granaries
being at 1-1/2, 2, 4, 6, 9, and 12-1/2 inches, as determined by
actual measurement on the spot.
In some cases, and especially where the soil is shallow, the
galleries and granaries are much crowded together, as is shown in
Plate IV., which represents a small mass of earth, pierced by the
roots of plants, taken out of a nest of _barbara_, lying at two
inches below the surface. When first opened all these granaries were
filled with seeds.
The shape of the granary chambers varies considerably, as may be
seen by reference to the drawing of three floors given in Plate
III., p. 23, and that shown diagrammatically in the woodcut on next
page, where the white space represents the granary floor, and the
dark circular spot in the centre, the aperture of a gallery leading
downwards.
I once had an opportunity of seeing a large portion of a nest of
the red-headed variety of _barbara_ laid bare by a cutting recently
made through a bank at Cannes in digging the foundations of a house,
which exposed a very extensive and complicated series of galleries
and granaries. The lowest point at which I detected the workings of
the ants was at twenty inches below the surface of the ground, and
here granaries containing seeds in abundance were present, and the
galleries and granaries extended over a space measuring 5ft. 9in.
in a horizontal direction. In two cases I have found nests of _Atta
barbara_ at Mentone which were carried far into the living rock
in places where it happened to be of an even grain, and not gritty
or pebbly as it frequently is. It was quite by chance that I first
discovered this very interesting fact, having tracked a train of
seed-bearing workers to a part of the sandstone rock where steps had
quite recently been hacked out leading to some terraces.
[Illustration]
[Illustration: _Plate V._]
I soon saw that the ants entered and came out from three or four
small passages in the cleft surface of the rock, and that their nest
actually lay in the sandstone itself. Having contrived to wedge off
several large flakes of the rock, which was soft in most places and
might be scooped out with a strong knife, I discovered that though
some of the passages of the ants followed the lines of cleavage and
the cracks made by the fine wiry fibres of the bushes growing on the
surface, others were frequently made in the form of tubular tunnels
through the living rock. Without the aid of hammer and chisel it was
not possible to follow the galleries and to secure specimens of the
mined rock; but on the next day (Dec. 7th) I returned armed with
tools, and with the assistance of a friend[30] quarried out a portion
of the nest, tracing it down eventually to twenty-three inches below
the surface of the rock in a vertical, and to about sixteen inches
away from the surface in a horizontal direction.
[Footnote 30: I take this opportunity of expressing my thanks to Mr.
Robert Lightbody for help on this and other occasions.]
At one point where the rock was almost entirely solid and without
flaw or crevice, and where it was clear that the passages were
entirely the work of the ants, we measured a tunnel by worming
a straw down it, and found it to be ten inches in length. We
subsequently traced this tunnel or rock gallery down until it
communicated with a chamber filled with winged ants and seeds of
several kinds. This granary was horizontal, and merely an enlargement
of an ordinary gallery of a compressed spindle-shape, flattened from
above downwards, measuring as nearly as I could estimate three inches
in length, by a trifle less than an inch in breadth, and half an
inch in height. The walls were tolerably smooth, but not prepared or
glazed in the way that certain small terminal cells which I shall
shortly describe were. The surfaces, however, had a very different
appearance to that of the surrounding sandstone, being of a darker
and brownish colour, and seeming to be coated with some kind of
dressing or cement.
One of these tunnels at first took a horizontal course for two and a
half inches, then descended vertically for an inch and a half to a
point where it made two horizontal branches, and from these latter
several other vertical galleries descended, two of which we were able
to trace until they expanded into a cluster of small pear-shaped
cells, the walls of which were quite smooth and very carefully laid
with plates of mica and cement. I was able to draw this on the spot,
Fig. A, Plate V., while Mr. Lightbody worked it out piecemeal with
hammer and chisel. It was unfortunately impossible to secure more
than very imperfect fragments as specimens. These terminal cells
were empty when we came to them, but it is quite possible that the
ants may have conveyed away larvæ or winged ants from them, having
received abundant notice of the coming danger from the continued
jarring of the chisel-work.
One entrance to this nest lay in a small accumulation of soil in a
hollow of the rock, and it was at this point that the refuse from
the nest was cast out. Indeed, had it not been for the accidental
circumstance of my having traced the ants to the newly hewn step in
the sandstone, I might never have discovered the fact that the nests
are sometimes carried deep into the living rock.
[Illustration: _Plate VI._]
With this to guide me, however, I succeeded in finding a second nest
of the same kind, and here I was able to secure better specimens
of the tunnels for drawing (Figs. B, B 1, Plate V., p. 33). These
drawings may be taken as representing also the size and shape of the
tunnels in the former nest, which were for the most part like these,
beautifully cylindrical, as is shown in the front view of the tunnel
at B 1. In one nest of _barbara_ I found a curious hollow spherical
dome, about an inch in diameter, the walls of which were constructed
of hardened earth about two lines thick, and having a large circular
aperture at the top and a very small one below (Figs. D and D 1,
Plate VI.). This dome was imbedded below in earth which adhered to
it, but it was otherwise easily separable from the soil; its inner
walls were smoothed with great nicety.
It has been suggested to me that this spherical chamber was
originally the work of a scarabæus, which had chanced to bury the
ball containing its eggs close to the nest of the ants, and that
the latter had appropriated it after the departure of the beetle
grubs. This may perhaps have been the case, but the dome was rather
larger than the ball usually formed by the scarab beetle, and I have
never seen one of these balls surrounded by a hardened case. The
chamber thus constructed was employed as a granary, and filled, as
well as the adjacent passages, with the grain of a grass (_Tragus
racemosus_), still enclosed in the husks, among which I detected
several ants at work, and also some minute white semi-transparent
creatures, like spring-tails (_Podurus_), which abound in these ants'
nests. Besides this spring-tail it is common to find in the galleries
and granaries of _Atta structor_ and _A. barbara_, certain silky
yellowish-white "silver fish" (_Lepisma_), a small white woodlouse
which does not roll itself into a ball, and at times the larvæ of an
elater beetle. I have observed on more than one occasion that when
in digging into an ant's nest I have thrown out an elater larva,
the ants would cluster round it and direct it towards some small
opening in the soil, which it would quickly enlarge and disappear
down. At other times, however, the ants would take no notice of
the elater, and it is my belief that the attentions paid to it on
former occasions were purely selfish, and that they intended to avail
themselves of the tunnel thus made down into the soil, with a view of
reopening communications with the galleries and granaries concealed
below, the approaches to which had been covered up. I have frequently
watched the ants make use of these passages mined by the elater on
these occasions.
At one time I suspected that the elater larvæ might consume the
seeds stored by the ants, and I therefore confined some of them in a
tumblerful of earth and seeds; but at the end of three weeks, though
the larvæ were strong and healthy-looking, I could not detect that
any of the seeds had been touched, and even those which had sprouted
remained uninjured. I have searched in vain for the beetles and
staphylinidæ which are known to inhabit certain ant's nests. In one
nest I found (on Dec. 28) a quantity of small spherical, egg-like
galls, slightly larger than but resembling the fruit of _Fumaria
capreolata_, spotted with pink-brown on a yellowish or greyish
ground. There was a dark spot at the point at which the mature insect
would emerge, and one did escape from the egg-like cocoon while I
was watching, and proved to be a _Cynips_ of very small size, but
furnished with a terrible dart for puncturing its prey.
It seems difficult to understand how it comes that these galls are
systematically placed among the seeds, for it was evidently no chance
occurrence, and I can only conjecture that the worker ants may have
brought them in and stored them under the impression that they were
really seeds! Even ants make mistakes, and of this I have given
an example above (p. 19). Though I have frequently found colonies
of several distinct species of ants inhabiting nests made in the
earth traversed by the widespread galleries of _Atta structor_ and
_barbara_, I have never detected any intermixture of species in the
chambers of a nest,[31] and but rarely found even the galleries and
entrance used in common by more than one species. On one occasion
when opening a nest of _structor_ I cut through a colony of the tiny,
large-headed, yellow ant _Pheidole megacephala_, lying in the midst
of, though distinct from, the former. When, however, it chanced that
one of the _structors_ fell from the crumbling earth into the midst
of the _Pheidoles_, it was curious to see how fiercely it would
be attacked, and with what terrified speed it would scamper off,
without attempting any resistance, and often carrying two or three
_Pheidoles_ hanging on to its legs.
[Footnote 31: Except in a few cases where I have seen one or two
_structors_ in nests of _barbara_ and _vice versâ_, and in the
curious instance to be mentioned below, where one colony consisted
of nearly equal parts of _structor_, _barbara_, and the red-headed
variety of _barbara_.]
Accidentally in this way battles do sometimes take place between
ants of different species; but by far the most savage and prolonged
contests which I have witnessed were those in which the combatants
belong to two different colonies of the same species.
_Atta barbara_, _Formica cruentata_, _F. erratica_, and especially
_Myrmica cæspitum_ may sometimes be seen fighting in this desperate
fashion. Rival colonies of _Myrmica cæspitum_ often gather for the
battle into dense masses three or four inches deep, and the place of
conflict will be seen on the following day strewn with the dead, and
this though the majority of the slain are carried off for food by the
victors.
But the most singular contests are those which are waged for seeds
by _A. barbara_, when one colony plunders the stores of an adjacent
nest belonging to the same species, the weaker nest making prolonged
though, for the most part, inefficient attempts to recover their
property.
In the case of the other species of ant which I have watched
fighting, the strife would last but a short time--a few hours or a
day--but _A. barbara_ will carry on the battle day after day and week
after week. I was able to devote a good deal of time to watching
the progress of a predatory war of this kind, waged by one nest of
_barbara_ against another, and which lasted for forty-six days, from
Jan. 18 to March 4!
I cannot of course declare positively that no cessation of
hostilities may have taken place during the time, but I can affirm
that whenever I visited the spot, and I did so on twelve days, or
as nearly as possible, twice a week, the scene was one of war and
spoliation such as that which I shall now describe.
An active train of ants, nearly resembling an ordinary harvesting
train, led from the entrance of one nest to that of another lower
down the slope, and fifteen feet distant; but on closer examination
it appeared that though the great mass of seed-bearers were
travelling towards the upper nest, some few were going in the
opposite direction and making for the lower. Besides this, at
intervals, combats might be seen taking place, one ant seizing the
free end of a seed carried by another, and endeavouring to wrench it
away, and then frequently, as neither would let go, the stronger ant
would drag seed and opponent towards its nest. At times other ants
would interfere and seize one of the combatants and endeavour to drag
it away, this often resulting in terrible mutilations, and especially
in the loss of the abdomen, which would be torn off while the jaws
of the victim retained their indomitable bull-dog grip upon the
seed. Then the victor might be seen dragging away his prize, while
its adversary, though now little more than a head and legs, offered
a vigorous though of course ineffectual resistance. I frequently
observed that the ants during these conflicts would endeavour to
seize one another's antennæ, and that if this were effected, the ant
thus assaulted would instantly release his hold, whether of seed or
adversary, and appear utterly discomfited. No doubt the antennæ are
their most sensitive parts, and injuries inflicted on these organs
cause the greatest pain.
It was not until I had watched this scene for some days that I
apprehended its true meaning, and discovered that the ants of the
upper nest were robbing the granaries of the lower, while the latter
tried to recover the stolen seeds both by fighting for them and by
stealing seeds in their turn from the nest of their oppressors.
The thieves, however, were evidently the stronger, and streams of
ants laden with seeds arrived safely at the upper nest, while close
observation showed that very few seeds were successfully carried on
the reverse journey into the lower and plundered nest.
Thus when I fixed my attention on one of these robbed ants
surreptitiously making its exit with the seed from the thieves' nest,
and having overcome the opposition and dangers met with on its way,
reaching after a journey which took six minutes to accomplish, the
entrance to its own home, I saw that it was violently deprived of its
burden by a guard of ants stationed there apparently for the purpose,
one of whom instantly started off and carried the seed all the way
back again to the upper nest.
This I saw repeated several times.
After March 4 I never saw any acts of hostility between these nests,
though the robbed nest was not abandoned. In another case of the
same kind, however, where the struggle lasted thirty-one days, the
robbed nest was at length completely abandoned, and on opening it I
found all the granaries empty with one single exception, and this
one was pierced by the matted roots of grasses and other plants,
and must therefore have been long neglected by the ants. Strangely
enough, not one of the seeds in this deserted granary showed traces
of germination.
No doubt some very pressing need is the cause of these systematic
raids in search of accumulations of seeds, and there can be little
doubt that the requirements of distinct colonies of ants of the same
species are often different even at the same season and date. Thus
these warring colonies of ants were active on many days when the
majority of the nests were completely closed; and I have even seen
these robbers staggering along, enfeebled by the cold, and in wind
and rain, when all other ants were safe below ground. It may be that
unusual exertions are necessitated by some exceptional demands made
by the condition of the larvæ of the winged male and female ants, and
I have observed that these latter appear at very various periods.
Thus I have seen winged males and females in the nests of _barbara_
on November 10, December 6, February 2, and March 10; and in those of
_structor_ on February 23, 29, March 13, and April 6.
Though _structor_ and _barbara_ make seed collecting the business
of their lives, they will, at least in times of scarcity, eagerly
devour animal food if it happen to fall in their way, and in the
harvesting trains a few ants may occasionally be seen carrying small
dead insects and the like. Once I threw a dead grasshopper down close
to a nest of _barbara_; it was immediately seized upon, and--after
strenuous efforts had been made to dismember it above ground, some
ants straining back the legs and wings, while others rushed in to
gnaw at the muscles where the tension was greatest,--carried down
below. On the following morning the wings of the grasshopper were to
be seen on the rubbish heap in front of the nest. Dead house-flies
and the larvæ of bees or wasps were at times readily devoured by
my captive ants (_barbara_). I have also seen large numbers of
_structors_ engaged in picking the bones of a dead lizard, and
was once a witness of the following singular contest between a
soft-bodied, smooth, greyish caterpillar, exactly an inch in length,
and two medium-sized _barbara_ ants. The ants were mere pigmies in
comparison of their prey, for as such I believe they regarded the
caterpillar, but they gripped its soft body with set mandibles,
showing the most savage determination not to loose their hold.
When I first detected the group the war was being waged in a tuft
of grass over one of the entrances to the ants' nest, and the
caterpillar was striding along the leaves, or thrusting itself
between the culms in the hope to shake off or brush away its little
persecutors. From time to time the caterpillar would turn viciously
round and endeavour to pluck away its assailants, but though it
actually succeeded in stripping off by means of its forelegs and
mouth five of the six legs of one of the ants which was within its
reach, they never once released their hold.
At length a chance movement of mine shook the grass leaf on which
they were, and ants and caterpillar rolled together down a steep and
rocky slope to about four feet distant. They tumbled over and over
several times, but still the ants gripped their prey as firmly as
ever.
The last endeavour of the giant victim was to rub off the ants by
burrowing into the soil, but on uncovering its retreat, I saw that
their positions were still the same. After watching this struggle for
twenty minutes, time failed me, and I returned home, carrying with
me, however, the combatants; and when on my return I opened the box
in which they were imprisoned, these bull-dog ants were clinging with
mandibles locked as firmly as ever, and now as I write, in death they
are clinging still, drowned in a sea of spirits of wine.
During the winter and spring I kept two colonies of _barbara_ captive
in the house, placed in separate glass jars, each of which might
perhaps hold half a gallon. The former of these colonies was taken on
December 18; but neither the queen ant nor larvæ were found, though
there probably were larvæ in some unexplored part of the nest, and
the ants were always restless and miserable, unceasingly trying to
escape, and dying in large numbers.
On February 12 I found that all these ants, though abundantly
supplied with seeds and all other kinds of food, were dead. Two other
colonies of ants, however, which had been taken in a torpid state
in the masses of earth which formed part of the original nest, were
alive and well, though still torpid.
The second captive colony, taken on December 28, with the wingless
queen ant and quantities of larvæ, formed a strong contrast with the
previous one. Here the ants at once set to work upon the construction
of galleries and safety places for the larvæ below the even surface
of garden mould on which I had placed them within the jar; for in
this case I did not attempt to preserve any portion of their own
nest. This was done at 3.30 P.M., and by 9 that evening I found the
ants most busily at work, having in less than six hours excavated
eight deep orifices leading to galleries below, and surrounded these
orifices by crater-like heaps, made of the earth pellets which they
had thrown out. I have observed somewhat similar structures raised
by _barbara_ after the nests have been closed on account of rain,
and _structor_ frequently raises still more elaborate and distinct
craters, such as those represented at Fig. B, Plate II., p. 22
(reduced one-half).
On the following morning the openings were ten in number, and the
greatly increased heaps of excavated earth showed that they must
probably have been at work all night. The amount of work done in this
short time was truly surprising, for it must be remembered that,
eighteen hours before, the earth presented a perfectly level surface,
and the larvæ and ants, now housed below, found themselves prisoners
in a strange place, bounded by glass walls, and with no exit possible.
It seems to me that the ants displayed extraordinary intelligence
in having thus at a moment's notice devised a plan by which the
superabundant number of workers could be employed at one time without
coming in one another's way. The soil contained in the jar was of
course less than a tenth part of that comprised within the limits of
an ordinary nest, while the number of workers was probably more than
a third of the total number belonging to the colony. If therefore
but one or two entrances had been pierced in the soil, the workers
would have been for ever running against one another, and a great
number could never have got below to help in the all-important
task of preparing passages and chambers for the accommodation of
the larvæ. These numerous and funnel-shaped entrances admitted of
the simultaneous descent and ascent of large numbers of ants, and
the work progressed with proportionate rapidity. After a few days
only three entrances, and eventually only one remained open. Yet
for weeks this active work went on, and the ants brought up such
quantities of earth from below that it became difficult to prevent
them from choking up the bottle containing their water, which they
repeatedly buried up to the neck. On January 10 the surface of the
earth was raised from an inch and a half at its lowest, to three
inches at its highest point above its original level, and this bulk
of excavated earth represented the amount of space contained in
their galleries and chambers constructed below. It was not, however,
until nineteen days after their capture that the ants began to form
systematic trains to carry down the seeds which I placed for them
on the surface, and I suppose that they had required this time for
the construction and consolidation of the granary chambers. From
this time forward the ants came out repeatedly in greater or less
force to gather in the various seeds with which I supplied them.
Indeed, throughout the whole of their captivity they seemed to be
perfectly contented with their lot and free from disease, remarkably
few ants dying or appearing feeble, and as far as the limited space
would permit they reproduced most of the habits which I had noted as
belonging to them in a wild state, such as the formation of a rubbish
heap; bringing out refuse materials, gnawed and empty seed-coats, the
ends of radicles, and root fibres which had penetrated their nest,
and laying sprouted seeds in the air to dry after having gnawed off
the radicle in order to arrest their growth.
I was also in this way able to see for myself much that I otherwise
could not have seen. Thus I was able to watch the operation of
removing roots which had pierced through their galleries, belonging
to seedling plants growing on the surface, and which was performed
by two ants, one pulling at the free end of the root, and the other
gnawing at its fibres where the strain was greatest, until at length
it gave way. Again the habit of throwing sick and apparently dead
ants into the water, the object of which was in part, I imagine,
to be rid of them, and partly perhaps with a view to effecting a
possible cure, for I have seen one ant carry another down the twig
which formed their path to the surface of the water, and, after
dipping it in for a minute, carry it laboriously up again, and lay it
in the sun to dry and recover; thirdly, the stripping off the coats
and husks of seed and grain swelling and on the point of sprouting,
previous to eating it; and finally, the actual eating of the contents
of the seed.
Most of these operations are usually performed below ground, and
even in my captive nest it was but rarely that I could get a glimpse
of their subterranean life, as they avoided the glass as much as
possible, though it was carefully covered with flannel and black
paper; and it was only by having the nest constantly before me on my
table, and thus becoming a witness of their operations day and night
during four months, that I detected them in positions which permitted
me to watch these actions of theirs.
The ants were in the habit of coming out in numbers of an evening
to enjoy the warmth and light of my lamp, and it was on one of
these occasions that I first observed them in the act of eating.
I perceived that in the midst of the black mass of ants gathered
together on the side of the glass jar one was holding up a white
roundish mass about as big as a large pin's head. Having turned a
stream of bright light passed through a condenser on this group, and
being permitted by the ants to make free use of my pocket lens, I was
able to see the details with great precision. The white mass appeared
to be the floury portion of a grain of millet, and I could see that
two or three ants at a time would scrape off minute particles with
their toothed mandibles, and take them into their mouths, repeating
the operation many times, before giving place to other ants, and
often returning again. It certainly appeared to be a _bonâ fide_
meal that they were making, and not merely an act performed for the
benefit of the larvæ, as when they detach crumbs from a piece of
bread and carry them below into the nest. However, I must own that,
though I subsequently dissected ants taken in this act, which I
suppose to be that of eating, I was unable by the use of the iodine
test to detect starch grains in their stomachs.
Still it seems quite possible that this failure may have been due to
my not having allowed the ants sufficient time to swallow their food,
as I killed them almost immediately after disturbing them at their
meal.
After having twice observed the ants eating as above described, I
made some experiments in feeding them myself.
They immediately seized and set to work upon a minute ball of flour
which I cut out from the centre of a grain of millet, taken from a
heap in front of a nest of _A. structor_, which had begun to sprout
and been deprived of its radicle and dried. A similar ball taken
from a sprouting grain of millet, but the growth of which had not
been arrested, was also partially eaten; but the hard, dry flour
taken from a grain of the same in its natural state, not moistened,
was at once rejected and thrown on the rubbish heap. The fat, oily
seed leaves of the hemp, however, were eagerly taken, though not
softened by water, their peculiar texture allowing the ants to
scrape off particles, as in the case of the ball of flour of the
sprouted millet. Under ordinary circumstances the hard shell of
the hemp-seed, and the coats of most other small fruits, grain, and
seeds, would prevent the ants from getting at the contents while
dry, but in the earliest stage of sprouting the shell parts of
itself, allowing the radicle to protrude, and then they find their
opportunity. (See Figs. A, A 2, Plate VI., p. 35.)
It has always been supposed that ants, from the delicate nature of
their mouth organs, were only able to lap up liquids or to swallow
very soft animal tissues, and one of the great difficulties in the
way of admitting that they might collect seeds for food, lay in the
apparent impossibility of their eating such hard substances. But
it has generally been overlooked that not only are all seeds soft
when moistened with water and ready to grow, but also that there are
certain kinds of seeds the contents of which are naturally soft.
The most important organs in an ant's mouth are shown in Fig. D 2,
and D 3, in Plate I., p. 21. D 3 represents one of the horny, toothed
mandibles, which serve admirably for scraping off particles of flour
from the seeds. Within these are the parts shown at D 2, where the
outermost pieces are the maxillæ and their four-jointed palpi or
feelers, and the innermost piece the labium and its three-jointed
palpi, between which the end of the delicate membranous tongue
appears.
I repeatedly placed leaves from the orange trees covered with cocci
and aphides from rose-bushes and pine trees, all of which are eagerly
sought by several other kinds of ants, in the captive nest, but the
ants never looked twice at them, and this corresponds with the fact
that I have never seen either _structor_ or _barbara_ attending on
or searching for aphides and the like. These captives took part of a
small quantity of honey which I placed in the nest, but displayed no
eagerness about it, and soon neglected and allowed it to be covered
up with earth thrown out from the nest.
The ants work very frequently at night during the dark,[32] and this
is the case in the wild as well as in the captive nests. A friend,
at my request twice visited a nest of _structor_ ants in the garden
of an hotel at Mentone, when it was quite dark (in March, between
seven and eight o'clock P.M.) and no moon, but the light of a candle
showed that the workers, both large and small, were busily engaged
in carrying into the nest seeds which had been purposely scattered
in their neighbourhood. I have myself seen _Pheidole megacephala_
similarly engaged at about nine P.M. on a warm night in April, when
it was perfectly dark, not even the stars showing; but in this
case the ants were collecting from the weeds in the garden. On the
same occasion I also observed long and active trains of _Formica
emarginata_ [a rather small dusky ant, with a yellow thorax], making
for the orange-trees in search of cocci and aphides, just as if it
were broad day.
[Footnote 32: This bears out the much-questioned assertion of
Aristotle, though he only claimed that ants work "by night when the
moon is at the full."--Hist. Anim., lib. ix. cap. xxvi.]
Before leaving Mentone, on May 1, I turned out this second captive
nest, and found that the colony appeared perfectly healthy, and
did not seem to have diminished materially in numbers. The queen
ant and the larvæ seemed to be in just the same state as when they
were taken. The earth in the lower part of the jar was honeycombed
with galleries, granaries, and cells, constructed quite as in the
wild nests, but more crowded together. The granaries were in many
instances full of seeds, which, though very wet, [the surrounding
soil being extremely moist on account of there being no drainage to
carry off the water which I was obliged to sprinkle from time to time
over the surface of the nest], still showed no trace of germination
that I could detect. The ants were therefore able to exercise the
same influence over these seeds, under the strange conditions of
their captive state, that they do in their natural homes.
The foregoing remarks, as has been stated above, refer for the most
part to only one of the three kinds of harvesting ants which I have
observed on the Riviera--that is to say, to _Atta barbara_, the
jet-black ant.
As far as the manner of collecting and storing the seed is concerned,
all that has been said of _Atta barbara_ applies with equal truth to
_A. structor_.
_A. structor_ is, however, less frequently seen above ground from
December to March than _barbara_, and is more frequently found in or
near the streets and gardens of a town.
The fourth species, on the other hand, the little _Pheidole
megacephala_, differs in several particulars. This ant appears to
shun the daylight, and to be most active at night, when, in the warm
weather at the end of April, it may frequently be seen carrying large
quantities of seeds into its nest. I have rarely observed it at work
in the daylight, so that my knowledge of its habits is but small. Nor
have I succeeded in discovering its subterranean granaries, though
I have opened several nests. Still, I believe that it is a true
harvesting ant, and not merely a casual collector of seeds. Of the
habits of _Pheidole pallidula_, a very closely allied and similar
species, but one less frequently met with, I cannot speak with
certainty, though it is quite possible that it also may be a true
harvester, in which case it would add a fifth species to this class.
Both _Pheidole megacephala_ and _Ph. pallidula_ appear to remain
inactive, or nearly so, during the months from November to April, and
it is probable that they are only to be seen in full activity during
the summer when I am not there to watch them.
There can be little doubt that any naturalist who will take the pains
to note the habits of ants on the shores of the Mediterranean through
June, July, August, and September, might collect a most interesting
series of observations on harvesting and other species, and add to,
and perhaps modify, those which my limited opportunities have enabled
me to make.
There are three other ants[33]--namely, _Formica emarginata_, _F.
fusca_, and _Myrmica cæspitum_, which may also occasionally be found
carrying a few seeds, but this is the rare exception, as far as my
experience goes, these species living on honey dew, sweet secretions,
and animal matter, like the great majority of ants all over the
world. I have never found seeds in the nests of any ants except those
of _Atta barbara_ and _A. structor_, though I have carefully searched
for them in most of the nests of the sixteen species of ants whose
habits I have watched.
[Footnote 33: For some details of the habits of the sixteen species
of ants observed on the Riviera, see Appendix A.]
There is every probability that these harvesting ants will be found
all round the shores of the Mediterranean, but the only points at
which I have positively heard of the existence of the habit besides
Mentone, Cannes, and Marseilles, are Capri[34] and Algiers. I am
indebted to Miss Forster for having, during a short visit to Algiers,
devoted some time to watching the habits of the ants in a garden at
that place. These observations were made in April last (1872), when
the three following species were watched:--
[Footnote 34: Where a harvester, probably _Atta barbara_, has been
observed by Mr. Buchanan White. See Appendix C.]
(1) _Formica (Cataglyphis) viatica_, a large, long-legged, blackish
ant, with orange-red and semi-transparent thorax, which never carried
seeds, but lived on animal food, especially flies. (2) _Formica
(Tapinoma) nigerrima_,[35] a rather small dusky ant, which brought in
some seeds to its nest, but principally "animal food, flies, small
worms," &c., and which did not carry the hemp and canary seed strewed
in their path, though on one occasion when Miss Forster scattered
some split hemp seed, they eagerly fastened upon the contents, and
ate some on the spot, while they transported the greater part to
their nest, and (3) _Atta barbara_, which, as on the Riviera, was a
true and most active harvester, and eagerly seized upon the hemp and
canary seed when these were placed in its way.
[Footnote 35: Mr. Smith thinks that this ant is either _F.
nigerrima_, of Nylander, or a new species, but it was not possible
for him to pronounce with absolute certainty as he had only two
specimens of workers from which to judge.]
_Recapitulation and Concluding Remarks._
There are some points of interest suggesting openings for future
observation, to which I will now allude, making at the same time a
partial recapitulation of what has gone before.
We have learned in the first place that the ancients had facts
on their side when they said that the ant is one of the very few
creatures which lays up supplies of food sufficient to last for
months, or even perhaps, as Bochart says, for a whole year; and
though we cannot quite accept the statement that "there is no animal
except men, mice, and ants, that stores its food,"[36] they were
right in saying that the habit is a most singular and interesting
one. It is probable, however, that the old writers may have fallen
into the error of supposing that all ants were harvesters, though the
truth appears to be, that even in hot climates, it is only a very
small number of species that are so. The fact that certain ants in
Southern Europe do store large quantities of sound seed in damp soil,
and check their tendency to germinate, may be thought to favour the
possibility of the existence of those deeply hidden supplies of seed
which, though they have never been detected, are popularly supposed
to explain the sudden appearance of the crops of weeds on soil newly
brought out from great depths.
[Footnote 36: Sophian, quoted by Bochart in his Hierozoïcon, ii. cap.
xxi, p. 497.]
The argument may be stated thus: seeds remain for months undecayed,
and still capable of germination, at depths varying from one to
twenty inches below the surface of the soil in certain ants' nests,
why should they not lie hidden for indefinite periods in ordinary
soil?
To answer this positively, experiments should be made[37] in order
that we might learn whether these seeds can retain their vitality
without sprouting in moist soil; but the general belief is that under
these conditions they will do one of two things, they will either
grow or rot. Be this as it may, one of the most curious points that
we have learned about these ants, is that they know how to preserve
seeds intact, even when within from one to three inches of the
surface of the ground, that is to say, at the actual depth at which a
gardener most frequently sows his seeds, though if these very seeds
are taken out of the granary and sowed by hand, they will germinate
in the ordinary way. It is possible that this may be in part due
to the compact nature of the floors and ceilings of the granaries,
these excluding air in some measure, though as moisture freely passes
through them, and there are always two or three open galleries
leading into the granaries, and which communicate directly with the
open air, I can scarcely accept this explanation as complete.
[Footnote 37: In order to try the experiment fairly, seeds taken
from ants' nests, or seeds of the same species as those which are
habitually found in ants' nests, should be placed at different depths
in the earth and examined after the lapse of six or eight months.
Why it is that certain seeds resist the influences which destroy
the vitality of other seeds of closely allied species is another
and a very curious but complicated problem, the explanation of
which may perhaps lie in the different chemical properties of the
seeds in question, in the more or less permeable character of their
seed-coats, or their general texture.]
The seeds do occasionally sprout in the nest, though it is extremely
rare to find instances of this, and then the ants nip off the little
root, and carry each seed out into the air and sun, exactly as the
old writers have described, and when the growth has been checked and
the seed malted by exposure, they fetch them in again. It is in this
condition that the ants like best to eat them, as I have proved by
experiments among my captives.
As the ants often travel some distance from their nest in search of
food, they may certainly be said to be, in a limited sense, agents
in the dispersal of seeds, for they not unfrequently drop seeds by
the way, which they fail to find again, and also among the refuse
matter which forms the kitchen midden in front of their entrances,
a few sound seeds are often present, and these in many instances
grow up and form a little colony of stranger plants. This presence
of seedlings foreign to the wild ground in which the nest is usually
placed, is quite a feature where there are old established colonies
of _Atta barbara_, as is shown at Fig. A in Plate I., p. 21, where
young plants of fumitory, chickweed, cranesbill, _Arabis Thaliana_,
&c., may be seen on or near the rubbish heap.
It would be interesting to make a list of all these ant-imported
plants, and I think it quite likely that, if a sufficiently large
number of nests were visited, some seedlings of cultivated species
might be found amongst them, for we have seen that garden plants are
frequently put under contribution.
One can imagine cases in which the ants during the lapse of long
periods of time might pass the seeds of plants from colony to
colony, until after a journey of many stages, the descendants of the
ant-borne seedlings might find themselves transported to places far
removed from the original home of their immediate ancestors. It is a
true cause, but at the same time it may be one which has, like many
true causes, exceedingly small effects. One can scarcely look at the
teeming population of an ant's nest, without asking whether there
are any checks to their increase, and if so, what these checks are.
I know very little of what foreign enemies they may have, though I
have occasionally seen them captured by lizards, _Cicindela_ beetles,
and spiders,[38] and it is well known that the females are eagerly
sought for by birds at the season when they are above ground, and
about to found new colonies; but I believe that ants are the ants'
worst enemies, for fearful slaughter and mutilation often result from
the encounter of armies of the same race, but belonging to different
nests.
[Footnote 38: I have seen the remains of ants at the bottom of
the tube of trap-door spider nests, and watched a hunting spider,
_Lycosa_, capture a large black ant (_Formica pubescens_), by
entangling it in threads, which it deftly spun about its limbs, while
running rapidly round the struggling victim in a circle, and dodging
out of the way of the ant's mandibles. In England one may frequently
see ants caught in the spiders' webs among the rose-bushes, and Mr.
Blackwall says, in his Spiders of Great Britain and Ireland, that
_Theridion riparium_ lives principally on ants.]
Harvesting ants have nothing to do, as far as I have been able to
discover, with aphides, cocci, and the like, nor do they seek for
any of those sweet secretions which are the staple food of the
generality of ants; they live, however, on very friendly terms with
certain yellowish-white and satiny-coated "silver-fish" (_Lepisma_),
which are found in the passages and chambers of the nests; but what
their relations are to these creatures and to certain beetles which
have been found in the nests of _Atta barbara_ in Spain and Syria
is unknown. It is possible that by carefully watching captive ants
in company with these creatures under very favourable conditions,
something further might be learned on this head. My captive ants
constructed all their chambers, granaries, and almost all their
galleries away from the glass, and in the interior of the earth,
though I tried to tempt them to work in parts more accessible to
sight by swathing the jar in flannel.
There is much to be learned, I do not doubt, about the friends and
enemies of harvesting ants; and another great desideratum is further
information as to the parts of the world in which they are found and
what causes may be assigned for the limitation of the habit.
What is the geographical distribution of the harvesting species,
and what the geographical distribution of the habit? For instance,
to quote Mr. F. Smith,[39] _Atta structor_, though not "found in
England, is scattered over a great part of Europe, having occurred in
France, Italy, Germany, Austria, Dalmatia, and Switzerland; it has
also been found in Algeria" and Syria; and _A. barbara_ is almost as
widely spread. May we then conclude that these species are harvesters
wherever they are found, and that they store seed in Germany and
Switzerland as freely as they do on the shores of the Mediterranean?
If this be really so, then Huber, whose attention was specially
directed to this point, and a host of laborious and scrupulous
observers of the Continent, have had the very fact under their eyes,
though they have been at considerable pains expressly to deny it.
I cannot think that this is likely, but it is a matter which could
easily be settled by those who travel or reside in Germany, Northern
France, or Switzerland.
[Footnote 39: Mr. F. Smith, On Some New Species of Ants from the Holy
Land, in Journ. Linnean Soc., London, vol. vi. p. 35.]
It seems to me more probable, however, that they do store in the
south, but not in the north; for all the difficulties which attend
the preservation of the seed in the granaries in the south would
be greatly increased in the wet climates of Northern Europe, and
there, moreover, the greater cold would render the ants torpid almost
throughout the winter, when food would not be required. But the
question is plainly an open one. We may also ask why it is that only
a very few out of the many species of ants which inhabit the shores
of the Mediterranean should possess this habit of collecting seeds,
and differ so widely in their manner of living, from their neighbours?
If we wish to put ourselves in the way to answer these queries,
the first thing we should do would be to examine and compare
the structure of the digestive organs and parts of the mouth in
harvesters and non-harvesters, with a view to seeing whether there
may not be some capital difference here.
These observations demand some skill in dissection and preparation,
and in regretting that it has not been in my power to make them, I
can only hope that some one more skilled than I am may undertake the
subject.
It seems probable, that in warmer latitudes there are many conditions
which favour the rapid increase of ants, so that a given tract of
country in Southern Europe, for example, must have on an average more
colonies to support than a similar tract in the north, and that to
meet this increase of population, it has therefore become necessary
for these creatures to seek their subsistence from as many and as
dissimilar sources as possible. The fierce conflicts over booty both
between rival nests of the same and of distinct species, tend to
show that, even as things are, they frequently have to fight for
their food.
Hitherto, as far as I have been able to learn, only nineteen true
harvesting ants have been detected in the whole world, limiting
this term to those species which make the collection of seeds the
principal occupation of their outdoor lives, and are evidently in the
main dependent upon this kind of food for subsistence.
Now if we compare these nineteen species of ants[40] together a very
curious fact forces itself upon our notice--namely, that all of them
are closely related, so much so that not only do all belong to the
same division of ants (the tribe _Myrmicineæ_), but that with one
exception (_Pseudomyrma_) all would have been placed by the great
Fabricius in one genus, _Atta_, and the one exception is not far
removed from it.
[Footnote 40: These are _Myrmica (Atta) barbata_, from Texas and
Mexico; _Œcodoma (Atta) cephalotes_, from Brazil and Mexico; _Œcodoma
(Atta) providens_, from India; _Œcodoma (Atta) diffusa_, from India;
_Atta rufa_, from India; _Pheidole (Atta) megacephala_, from South
France; _Atta barbara_, from South France, Capri, and Algiers; _Atta
structor_, from South France; and _Pseudomyrma rufo nigra_, from
India.]
We must not forget, however, that, as has been stated, there are
other ants which do occasionally collect seeds, and thus appear to
show traces of this remarkable instinct; but as far as I have yet
seen, it is always possible to distinguish them readily from true
harvesters. Still I think it very likely that in hot climates the
division between harvesters and non-harvesters may be bridged over by
a complete chain of intermediates. Here two more questions suggest
themselves for more complete future solution. (1) Do true harvesters
which store seed in granaries ever attend upon aphides and seek for
sweet secretions? (2) Do occasional harvesters ever form granaries?
In any case the name of "the provident one" is only, I suspect, fully
deserved by a limited number of ants, and Æsop, in his well-known
fable, might as properly have made the dialogue which ends in the
recommendation to "dance in winter as he piped in summer," take place
between two ants as between an ant and a grasshopper, as far at least
as their respective foresight is concerned.
Why it is that one ant should require stores of food in the winter of
which other ants have no need, is one of the many problems which only
patient watching and careful comparison and experiment can help us to
solve.
There are not wanting those among the many winter visitors of the
south who have time in abundance or superabundance at their disposal,
and might help to clear up these and many other mysteries, and to
them I would strongly recommend the study of the habits of plants and
animals as a pastime, if nothing more.
The way is open: it is not difficult to follow, and it leads to very
pleasant places.
APPENDIX.
A.
The following are the species of ants which I have observed on the
Riviera, and principally at Mentone; the actual locality where my
notes were taken being given in every case.
_Family Formicidæ._[41]
[Footnote 41: Ants have been divided into three tribes, the two first
of which, _Formicineæ_ and _Ponerineæ_, are distinguished by the
latter having a contraction in the abdomen not found in the former,
and both are separated from the third tribe, _Myrmicineæ_ by having
but a single scale on the petiole, while in _Myrmicineæ_ there are
always two nodes or protuberances on the petiole. It is important to
remember the difference between the first and the last named tribes,
as we shall find that all the true harvesters belong to _Myrmicineæ_.
I have not seen any of the representatives of the second tribe in the
south.]
_Tribe Formicineæ._--Petiole (or stalk which unites the thorax and
the abdomen) of one joint, and furnished with a single vertical
scale, abdomen not contracted.
(1) _Formica fusca_, Linn.--A rather large ant (3-1/2 to 4-1/2 lines
long), of a blackish ash colour, with a satiny sheen on the upper
half of the abdomen. Smells of formic acid when crushed. Lives upon
sweet secretions and animal matter, and occasionally carries a very
few seeds into its nest, which is made in the ground. (Mentone.)
(2) _F. emarginata_, Latr.--Of medium size (2-1/2 lines), brownish,
with yellow thorax. Has a strong smell of honey when crushed. Lives
principally upon sweet secretions, but occasionally carries a very
few seeds also. Nest in the ground. (Mentone.)
(3) _F. (Camponotus) cruentata_, Lat.--Large (5 to 6 lines), dusky
brown, with orange red on legs and abdomen. Strong smell of formic
acid. Lives on sweet secretions and animal matter, and has never
been seen by me carrying seeds. Nest in the ground. (Mentone and
Cannes.)
(4) _F. (Camponotus) marginata_, Latr.--Large (4 to 5-1/2 lines),
black. Has no perceptible smell even when crushed. Lives principally
on sweet secretions, and does not bring in seeds to its nest, which
is made in the ground. I have seen this ant at Cannes ascending the
cork oaks in search of certain cocci which resemble black and shining
berries rather larger than a pea, and which exude sweet secretions.
(Mentone and Cannes.)
(5) _Formica cursor_, Fonscol.--A rather large but slender ant (3 to
4 lines long), nearly black, with a faint bronzy hue, legs very long.
Smell not noted. Runs very swiftly, and is hard to catch; feeds on
sweet secretions, and does not carry seeds. Nest in ground. (Cannes.)
(6) _F._ (species undetermined).--A large ant (5 to 6-1/2 lines),
black brown with yellow thorax and legs. In shape resembles _F.
marginata_. Strong smell of formic acid. Habits not observed. Nest
found under a stone in a pine wood. (Cannes.)
(7) _F._ (species undetermined).--A rather large ant (3 to 4-1/2
lines), resembling _F. fusca_, but having the thorax yellow. Strong
smell of formic acid. Feeds on sweet secretions, and does not carry
seeds. Nest in ground. (Cannes.)
(8) _Formica (Tapinoma) erratica_, Latr.--Rather small (2 lines),
nearly black. Has a strong and most disagreeable smell, something
like rancid oil, which is emitted if the nest is disturbed or the
insect crushed. Lives upon sweet secretions and animal matter, but
rarely if ever carries seeds, and pays no attention to them if placed
in its path. It nests in the ground, and forms superficial covered
ways, roofed in with a thin crust of earth and vegetable fibres
cemented together. (Mentone, Cannes.)
_Tribe Myrmicineæ_. Petiole two jointed, furnished with two nodes
(protuberances).
(9) _Crematogaster (Myrmica) scutellaris_, Oliv.--Of medium
size (3-1/2 to 4 lines), nearly black, with yellowish red head.
Disagreeable smell like rancid oil when crushed. Erects the abdomen
when excited, and runs about with it turned up at right angles to
the body. Lives on sweet secretions, and does not carry seeds. When
dissecting the abdomen of this ant, I noticed that in freshly killed
specimens a drop of poison appears at the extremity of the sting,
which if brushed away will form again several times in succession.
Nest in the bark and wood of sick or decayed trees. (Mentone and
Cannes.)
(10) _C. sordidulus_, Mayr.--Very small (1-1/2 to 2 lines), resembles
_C. scutellaris_, but is uniformly black brown. No perceptible smell.
Lives on sweet secretions, and may frequently be seen inside flowers.
Nest in earth. Behaves like _C. scutellaris_ when excited. (Mentone
and Cannes.)
(11) _Myrmica cæspitum_, Latr.--Small (2 lines), brown. Faint smell
like peat smoke. Feeds on animal food and sweet secretions, and may
occasionally be seen collecting and carrying in seeds. Nest in the
ground. (Mentone and Cannes.)
(12) _Pheidole (Atta or Myrmica) megacephala_.--Very small (1-1/2 to
2 lines), yellow, the larger workers having enormous heads. Smell
very peculiar, and a trifle like aniseed when crushed. Appears to
be a true harvester, and not to seek for sweet secretions. Nest in
ground. (Mentone and Cannes.)
(13) _Ph. (Atta or Myrmica) pallidula_.--Very small (1-1/2 lines),
pale yellow, closely resembles _Ph. megacephala_, but is paler and
more transparent, and the larger workers have less disproportionate
heads. Smell not noted. Habits not fully observed. Nest in ground.
(Mentone.)
(14) _Atta (Aphenogaster or Myrmica) structor_.--Rather large (2 to 4
lines), of a claret brown. No smell when crushed. A true harvester,
and does not appear to seek for sweet secretions, though it will
occasionally take animal food. Nest in ground or under stones.
(Mentone and Cannes.)
(15) _Atta (Aph. or Myrmica) barbara_.--Rather large (2 to 4 lines),
jet black. No smell when crushed. Habits of _structor_. Nest in
earth, and more frequently in uncultivated ground. I have twice
seen a few ants coloured like _structor_ in colonies of _barbara_.
(Mentone, Cannes, and Marseilles.)
(16) _Atta (Aph. or Myrmica) barbara_ var.--A large ant (3 to 6
lines). The larger workers black, with red or mahogany-coloured
heads, the smaller most frequently black, and like those of _Atta
barbara_, of which this is probably only a variety. It differs
however in its smell, which, when the body is crushed, resembles that
of _Pheidole megacephala_, and is something like aniseed. Habits of
_structor_ and _barbara_. Nest in earth. On one occasion I opened
a large nest at Cannes, where the colony was composed in about
equal parts of ants which in colour and appearance might be said to
represent the three forms, _structor_, _barbara_, and the red-headed
variety of the latter. There were also a few ants with pale yellowish
brown heads. (Mentone and Cannes.)
B.
The following Indian species are described by the late Dr. Jerdon as
harvesters, in the Madras Journal Lit. and Sc. 1851:--
(p. 45). _Atta rufa._--"Its favourite food is dead insects and other
matter, but it also carries off seeds like the _Œcodoma_, chaff,"
&c. &c. (p. 46). _Œcodoma providens._--"Their common food I suspect
to be animal matter, dead insects, &c. &c., which at all events they
take readily, but they also carry off large quantities of seeds of
various kinds, especially light grass seeds, and more especially
garden seeds, as every gardener knows to his cost. They will take
off cabbage, celery, radish, carrot, and tomato seeds, and in some
gardens, unless the pots in which they are sown be suspended or
otherwise protected, the whole of the seeds sown will be removed in
one night. I have also had many packets of seeds (especially lettuce)
in my room completely emptied before I was aware that the ants had
discovered them. I do not know, however, if they eat them or feed
their larvæ on them, though for what other purpose they carry them
off I cannot divine. I have often observed them bring the seeds
outside their holes, as recorded by Colonel Sykes, and this I think
generally at the close of the rainy season; but in some cases I had
reason to believe that it was merely the husks, of which I have seen
quite heaps, and that the ants did not take them back to their nests.
If any of the forementioned seeds be sown out at once in a bed, most
likely in the morning the surface of the whole spot will be found
covered over with little ridges, the works of these creatures, and
the few seeds that perhaps remain, dug all round, and being carried
off sometimes above ground, at other times under ground. Their
galleries and subterranean passages are often very extensive, and it
is no easy matter to dig down to their nest to see what becomes of
the seeds." _Œcodoma diffusa_ has the same habits as _Œ. providens_.
Lieut.-Col. Sykes, _Descriptions of New Indian Ants_ in _Trans. Ent.
Soc. Lond._, i. 103 (1836).
_Atta providens_, Sykes. "In illustration of the habits of this
species of ant, I shall give the following extract from my
diary:--'Poona, June 19, 1829. In my morning walk I observed more
than a score of little heaps of grass-seeds (_Panicum_) in several
places on uncultivated land near the parade-ground; each heap
contained about a handful. On examination, I found they were raised
by the above species of ant, hundreds of which were employed in
bringing up the seeds to the surface from a store below; the grain
had probably got wet at the setting in of the monsoon, and the ants
had taken advantage of the first sunny day to bring it up to dry.
The store must have been laid up from the time of the ripening of
the grass-seeds in January and February. As I was aware this fact
militated against the observations of entomologists in Europe, I was
careful not to deceive myself by confounding the seeds of a _Panicum_
with the pupæ of the insect. Each ant was charged with a single seed,
but as it was too weighty for many of them, and as the strongest had
some difficulty in scaling the perpendicular sides of the cylindrical
hole leading to the nest below, many were the falls of the weaker
ants with their burdens from near the summit to the bottom. I
observed they never relaxed their hold, and with a perseverance
affording a useful lesson to humanity, steadily recommenced the
ascent after each successive tumble, nor halted in their labour until
they had crowned the summit, and lodged their burden on the common
heap.'"
(p. 104). "On the 13th of October of the same year, after the closing
thunderstorms of the monsoon, I found this species in various places
similarly employed as they had been in June preceding; one heap
contained a double handful of grass-seeds. It is probable that the
_Atta providens_ is a field species of ant, as I have not observed it
in the houses."
C.
After the appearance of a brief notice of a communication which I
sent in the winter of 1871-72 to the London Entomological Society,
announcing the fact that certain ants harvest seeds in a systematic
way at Mentone, two papers were published, in which confirmatory
evidence of the existence of the habit in other parts of the world
was set forth--one by Mr. Buchanan White, and the other by the late
Mr. Horne.
Mr. Horne's account of his observations was published in _Hardwicke's
Science Gossip_, No. 89, p. 109 (for May 1, 1872), and runs as
follows:[42]--
"My notes carry me to the far East, where I have often watched
this most interesting class of insects, and briefly recorded my
observations--unfortunately cut short by illness, and the necessity
of return to Europe, which must be my apology for their want of
completeness.
[Footnote 42: I omit the preliminary portion, in which my
observations are erroneously stated to have been made at Nismes and
Capri.]
"But before transcribing, I would remind my general reader that
all ants may be seen carrying off food to their nests for present
consumption, and that this food consists of a great variety of
substances. This is disposed of inside the said nest, being often
masticated, and the juice extracted by the workers, and then given
in an inspissated form from their mouths to the young grubs, which
are in general tended by their nurses with the greatest care. It is
indeed very curious to watch this feeding process; but to proceed.
"Under date Nov. 7th, 1866, I find in my natural history note-book as
follows:--Mainpuri. This morning as I was walking across the 'Oosur,'
or waste plain, where it was very sandy, being cut into small
ravines, and clothed only here and there with fine grass disposed in
clumps, thus forming little hillocks of sand blown by the wind, and
arrested in its course by the grass, I came across a long line of
ants, travelling four deep, some coming empty, and others laden each
with one grass-seed, on their way home.
"I followed up the procession to the nest, which was subterranean,
and at the mouth of which on the level plain there was no trace of
elevation caused by the soil brought up from below, owing to the
habit of these ants of taking each grain of sand to some distance
along their road, and depositing it on one side or the other.
"There may have been five or six entrances to the nest, in and out
of which a prodigious number of ants were passing, the species
of which has been described by Dr. Jerdon. They were of a medium
size, shortish bodies, and of a reddish-brown colour--_Pseudomyrma
rufo-nigra_, Jerdon. Around the mouth of the nest, forming a circle
of perhaps eighteen inches in diameter, was a space beaten flat, and
kept clear by these said ants, from which radiated in every direction
thirteen roads, each about four inches in width for about thirty
to forty yards, when they branched off and became narrower, being
ultimately lost amongst the grass roots. These paths were fairly
straight; they did not cut through elevations, but went round them.
"From a careful examination it appeared that they had been cleared
of all obstacles, such as small stones, twigs, &c., but that their
smoothness resulted only from the tread of countless feet.
"The bearers of burdens took the seeds _into_ the nest, which I did
not dig up, and certainly stored them there, after having prepared
them, probably by the removal of a portion of the outer husk. Of
these husks there were large collections near the entrances to the
nest, all carefully set aside by the ants.
"In times of famine, I am told, not only are the nests rifled of
their grass-seed stores, but these heaps of apparent husks are
collected and ground with other grain to eke out a subsistence.
"This kind of grain has a name, 'Jurroon,' derived from 'Jharna,' to
sweep, literally sweepings. I much regret that I have not preserved
specimens of this 'Jurroon,' for it is very unlikely that the ants
after taking it to their granary, should again throw it out, and yet,
if grainless, what benefit could there be in eating it? The season
of the year when I observed them (November) is the beginning of the
cold weather, and no rain would probably fall (excepting a little at
Christmas) till next May or June. Later on seed would be rare; and
how the nest fares at a time when floods of water often pass over the
plain I cannot conceive.
"It is clear that some escape, and we know with what prodigious
rapidity these colonies increase. But these jottings have been
recorded merely to show how this species of ant store grain against a
time of scarcity, and fully bear out the statement in the text with
which I commenced this paper."
The following are Dr. Buchanan White's notes, alluded to above,
published in the _Transactions of the Entomological Society_ (London,
1872) part i., Proceedings, p. v.:--
"Capri, June 3, 1866. In the afternoon to the Punta Tragara, where a
colony of ants afforded us much amusement. These little insects had
a regular road, made by cutting away the grass and other plants in
their way. This road was about one inch and a half wide, and several
yards long, and led to a clump of plants in seed. Along this road
a long train of ants were perpetually travelling to the nest (or
_formicarium_), bearing with them pods of leguminous plants, seeds of
grass and of Composites (_Chrysanth. segetum_), &c.
"The perseverance with which a single ant would tug and draw a pod
four times his own length was very interesting; sometimes three or
four ants would unite in carrying one burden. Near the formicarium
was a great mass of débris, consisting of empty pods, twigs, emptied
snail shells, &c., cast out by the ants. The seeds appeared to be
stored inside the nest, as in one that I opened the other day I found
a large collection. The species was a black ant; the formicarium was
underground."
D.
_On Collecting and Examining Ants._
There are very few branches of natural history which might be more
easily followed by a traveller, or one who fears to encumber
himself with bulky collections difficult to transport from place to
place, than the study of ants. The whole European ant fauna might be
adequately represented by specimens preserved in spirit of wine and
packed in the compass of a hat-box.
In taking specimens of ants it is important never to put the
representatives of more than one nest in each bottle, but then in
most cases a sufficient number may be placed in a single bottle of
the size used for containing the smaller homœopathic globules. If
possible the winged male and female ants, as well as the wingless
workers, should be secured.
The ants die very quickly in pure spirit of wine, and they can
afterwards, even after the lapse of months or more, be pinned out in
the cabinet after having been washed in warm water. In examining the
mouth organs of an ant in order to determine by the aid of books to
what genus it belongs, it is best to relax the parts by first washing
away the spirit of wine, and then leaving the specimen for a day or
more in a stopper bottle partly filled with finely chopped laurel
leaves. It is probable that a drop or two of prussic acid on a bit of
sponge might act as effectually in rendering the tissues pliable.
A compound microscope is necessary for the final examination of the
joints of the labial and maxillary palpi (see Fig. D 2, Plate I.,
p. 21); but the neuration of the wing (D 1, Plate I.), another very
important character, is easily detected with a good pocket-lens.
The works which may most usefully be consulted are, for France, M.
Nylander's _Formicides de France et d'Algérie_, published in vol.
v. of the fourth series of the Zoological Division of the _Annales
des Sciences Naturelles_; for England, Mr. F. Smith's _Catalogue of
British Fossorial Hymenoptera_ (1856); and for a more general review
of the species in the world at large, Mr. F. Smith's _Catalogue of
Hymenopterous Insects in the Collection of the British Museum_, Part
vi., _Formicidæ_ (1858), and M. Mayr's _Beiträge zur Kenntniss der
Ameisen_, published in the _Verhandlungen des Zoologisch-botanischen
Vereines in Wien_, iii. 1853. _Abhandlungen_ (p. 101).
PART II.
TRAP-DOOR SPIDERS.
PART II.
TRAP-DOOR SPIDERS.
It is now one hundred and sixteen years since Patrick Browne gave an
illustration in his _Civil and Natural History of Jamaica_[43] of the
nest of a trap-door spider, the first record of the kind with which
I am acquainted. Seven years later the careful observations of the
Abbé Sauvages appeared,[44] in which he gave a very good description
of the nests of the "araignée maçonne" (_Nemesia cæmentaria_), which
he discovered near Montpellier, likening them to little rabbit
burrows lined with silk and closed by a tightly-fitting moveable
door. In 1778 and 1794 Rossi[45] published an interesting account of
the nest and habits of a trap-door spider which he had observed in
Corsica and near Pisa; and from that time up to the present day the
curious dwellings of these creatures, many species of which have been
discovered in warm climates, have continued to attract the attention
of naturalists.
[Footnote 43: P. 420, tab. 44, fig. 3 a. This work was published in
London in 1756.]
[Footnote 44: In Histoire de l'Acad. Royale des Sciences (Paris
1763), p. 26-30.]
[Footnote 45: Rossi (P.), Osservazione Insettologische (Memorie di
Matematica e Fisica della Società Italiana, vol. iv. (1778), and
Fauna Etrusca, vol. ii. (1794)).]
Very little, however, has been added to our knowledge of the
life-history of these remarkable architects for several years past,
and, indeed, I think it may be safely asserted that the study of the
habits and interdependence of the members of the animate world has
not, during the last fifty years, made anything like a corresponding
progress to that which may be seen in classification and description.
The microscope has led many who, a century ago, would have found
their chief delight in observing those points in the habits and
external characters of living creatures which the naked eye could
readily seize upon, to look much closer, to anatomize and describe in
detail every organism, great and small, and to examine every tissue
and cell.
It is, however, to the materials now being amassed by these modern
"cabinet naturalists" that recourse must be had if we wish to form
a true comprehension of the functions and habits of living things.
They must tell us, for example, what instruments, tactile and visual,
an animal possesses if we wish to understand how it constructs a
particular fabric, so that the "field naturalist" will have to apply
to his brother of the "cabinet" before he can turn his observations
to good account.
Still, the fact remains that the habits of plants and animals afford
many openings for careful investigation, and such as are especially
within the reach of those lovers of nature who have ample time at
their disposal, and the opportunity to spend it in a warm climate
where life abounds, and is never wholly checked even in the depth of
winter. It seems strange to think that collectors so frequently take
creatures out of wonderfully constructed nests and yet never observe,
or at any rate never describe, the structure of these fabrics.
Thus, for example, the dwellings of only eight out of the thirty-six
species of trap-door spider stated by Prof. Ausserer[46] to belong to
the Mediterranean region are known in books, those of the remaining
twenty-eight being, as far as I have been able to learn, yet to be
discovered. This is the more strange as from the nocturnal habits
of these creatures it is almost always necessary to dig them out
of their nests; indeed it is more than probable that if all the
dwellings which have been destroyed had been described, the following
pages would never have appeared.
[Footnote 46: Prof. Ausserer (Anton.), Beiträge zur Kenntniss der
Arachniden Familie der Territelariæ (Mygalidæ), in Verhandlungen der
k.k. Zool. Bot. Gesellschaft in Wien. Jahrg. 1871, Band xxi.]
Before proceeding to pass briefly in review what has been written on
the subject of trap-door spiders, it will be well to take one glance
at the relation which these spiders bear to their fellows. The great
order of spiders (_Araneæ_) has recently[47] been divided into seven
sub-orders, the fourth of which, _Territelariæ_, includes all the
trap-door spiders, and some others which do not construct trap-doors.
This sub-order corresponds with that which was formerly called
_Mygalidæ_, but this name, as well as that of _Mygale_, originally
given to all trap-door spiders, has been abandoned because this
latter name had previously been applied to a genus of Mammals, and it
was feared that confusion might arise.
[Footnote 47: Thorell, On European Spiders, in Nova Acta Reg. Soc.
Scient. Upsaliensis, ser. iii. vol. vii. fasc. 1 and 2 (1869-70).]
The _Territelariæ_ [or underground weavers] are distinguished from
all other spiders by the position of their falces,[48] which have
the fang directed downwards, and move vertically parallel to one
another. Thus when a victim is seized by one of the _Territelariæ_
it receives a downward blow, while other spiders strike sideways,
the falces moving in a horizontal or oblique direction. With very
few exceptions this sub-order may also be known by the presence of
four blotches of paler colour at the base of the abdomen underneath,
indicating the position of four air-sacs, almost all, or indeed
perhaps all, other spiders having but two.
[Footnote 48: Sometimes called mandibles. One of these is
represented, enlarged, at Fig. A 7. in Plate VII., p. 88.]
Certain species of _Territelariæ_ are the only spiders known to
construct nests closed with a door, and these creatures must be
admitted to rank among the first of Nature's handicraftsmen and
inventors.
The geometrical webs of many common spiders are very beautiful
structures, but these are for the most part only snares for prey, and
not permanent dwellings, although the cocoons in which the eggs are
placed are often most ingeniously contrived. Thus in the south we
may sometimes find an inverted balloon of strong silk about an inch
long attached to heath and other bushes, which, if examined during
the winter, will be found to contain in its centre a case enclosing
a mass of eggs about one-third the bulk of the entire cocoon.
This inner case is shaped exactly like the outer, and both have a
circular silk lid carefully closed, and the space between the two is
filled with a dense mass of golden-brown silk, which acts no doubt
as an excellent non-conductor. This cocoon is the work of _Epeira
fasciata_, a species apparently only found in southern Europe.
Other spiders again, such as _Theridion_,[49] suspend by a long
and delicate cord of silk a minute balloon, scarcely larger than
a seed-pearl, containing their eggs, which sways to and fro in
the lightest breath of air. But admirable as these cocoons and
geometrical snares are, the homes of these and of spiders generally
do not exhibit much contrivance or ingenuity, or cannot at any rate
be ranked in the same category as those of the trap-door spider. But
it may be asked, why should we admire the one more than the other,
since it is clear that the most squalid and mean-looking nest exactly
serves the purpose of its occupant, whether for shelter or defence,
and in many cases a spider might even say with truth that as for her
home it would not be so safe if it were not so dirty.
[Footnote 49: _Theridion variegatum_ (Bl.). _Ero tuberculata_, Koch.]
But the answer is simple: the trap-door spider's dwelling is to that
of common spiders what the Mont Cenis tunnel is to other tunnels, and
something besides.
What delights us is to see how by clever contrivance and great
perseverance new and multiplied difficulties have been overcome, and
dangers avoided, and the interest aroused is exactly proportionate to
the amount of these difficulties and dangers.
It is hoped that the following pages and their accompanying
illustrations will vindicate the claims of these spiders to the
marked attention and admiration which is here asserted to be their
due as architects and engineers.
There is but one British or North European representative of the
_Territelariæ_--namely, _Atypus piceus_ (or _Sulzeri_),[50] and this
creature does not appear to deserve the name of trap-door spider,
for in three nests which M. H. Lucas kindly showed me, preserved at
the Jardin des Plantes at Paris, the mouth of the tube was destitute
of any covering. I gathered from what I saw, and from what M. Lucas
told me, that these nests [which he had taken in the neighbourhood
of Paris], consist of a silk tube from eight to ten inches long,
of which about one inch only at the lower extremity penetrates the
earth, the remainder being carried upwards in an irregular and
sinuous course among the stems and leaves of small plants and grasses
to which it is attached. When the tube is removed from these supports
it collapses, and appears like a rather coarsely woven ribbon-shaped
strip of silk.[51]
[Footnote 50: Unless it should prove, as Prof. Ausserer suggests,
that the British _Atypus_ is distinct from the Continental, when it
would bear the name of _Atypus Blackwallii_. (Ausserer, l. c. p. 17).]
[Footnote 51: I have never been able to meet with an English specimen
of the nest of _Atypus_; but it would appear from the descriptions
that the English differ from the French nests in being subterranean,
and in having the mouth of the tube concealed by a loose flap of
silk. Mr. Blackwall says: [Spiders of Great Britain and Ireland, part
i. p. 14] "Dr. Leech has taken specimens of _Atypus Sulzeri_ in the
vicinity of London and Exeter. It excavates, in humid situations, a
subterraneous gallery, which is at first horizontal, but inclines
downwards towards its termination. In this gallery it spins a tube
of white silk, of a compact texture, about half inch in diameter....
Part of the tube hangs outside of the aperture to protect the
entrance."
It would be interesting to learn whether these differences
permanently distinguish the English from the French nests, and if so,
whether the spiders which construct them are not, as Prof. Ausserer
is inclined to believe, distinct also.]
Four types of trap-door nest, properly so called, may now be
distinguished in the world at large, and these are represented
diagrammatically in the following woodcut.[52]
[Footnote 52: Where all the figures, except C 1, and D 1, which are
of the natural size, are reduced to about one-third of the actual
size in large specimens.]
Of these two only (A and B) were known up to the present time, the
construction of which is much simpler than that of the two new types
(C and D), which I have hitherto only found at Mentone and Cannes.[53]
[Footnote 53: It must not be supposed that I have a sole or prior
claim to what may prove to be new and of interest in the following
observations on the Trap-door Spiders of the Riviera. This priority
belongs to the Hon. Mrs. Richard Boyle, to whom I owe it that I ever
took up the subject. It was, thanks to her guidance, that I first
became acquainted with these marvellously-concealed nests in their
native haunts, and to her active help that I finally arrived at a
comprehension of the different types of structure which they present.]
[Illustration]
It will be seen at a glance that A and B have but one door, while C
and D have two, these latter having a surface door, and also another
door a short way under ground.
All the nests consist of a tube excavated in the earth to a greater
or less depth, unbranched in all but D, and in every case lined with
silk, this lining being continuous with the lining of the door or
doors of which it forms the hinge.
I have found it convenient to distinguish these four types of nests
by the following names:--A, the single door cork nest, or shortly
the cork nest; B, the single door wafer nest; C, the double door
unbranched nest; and D, the double door branched nest.
The type B has only been found in the West India Islands, and is
chiefly distinguished from A by having a thin and wafer-like door,
wholly constructed of silk, without admixture of earth, lying on
rather than fitting into the aperture of the tube; while in A
the door is much thicker, made of layers of earth and silk, and
so contrived that it tightly closes the mouth of the tube, which
is bevelled to receive it, much as a cork closes the neck of a
bottle.[54]
[Footnote 54: Nests belonging to the type A, are represented in
Plates VII., p. 88, and VIII., p. 94.]
The West Indian nests are of a much tougher and coarser texture than
those which I have seen in Europe, and vary somewhat in the shape of
their tube, which is curved or straight, and sometimes has near its
lower extremity a short spur-shaped enlargement, giving to the whole
a ludicrous resemblance to a stocking, of which this spur is the heel.
Mr. Gosse,[55] in his _Naturalist's Sojourn in Jamaica_, has given
an admirable description of one of these single door wafer nests, the
work of _Cteniza nidulans_, which I cannot do better than quote:--
[Footnote 55: Gosse (P. H.), Naturalist's Sojourn in Jamaica (1851),
p. 115-118. See also for another description of the same nest
Latreille's Vues Générales sur les Araneides, in the Nouv. Ann. du
Muséum (Paris, 1832), tom. i. p. 73-4.]
The nest is "cylindrical, or nearly so, from four to ten inches deep,
and about one inch in diameter; the bottom is rounded; and the top,
which is at the surface of the soil, is closed very accurately with
a circular lid. They are not all equally finished, some being much
more compact, and having the lid more closely fitted than others.
Some have irregular bulgings, and ragged laminated offsets on the
outer surface; but all are smooth and silky on the inside.... The
mouth of the tube, and the parts near it, are very strong; the walls
here often having a thickness of from one-eighth to one-fourth of an
inch; but the lower parts are much thinner. The lid is continuous
with the tube for about a third of its circumference, and this part
may be called the hinge, though it presents no structure peculiar to
itself; it is simply bent at a right angle, as is manifest, if a nest
be cut longitudinally through with scissors, the incision passing
through the midst of the lid. The mode of construction, I judge, from
examination of many nests, to be this. The spider digs a cylindrical
hole in the moist earth, with her jointed fangs or mandibles,
carrying out the fragments as they are dislodged. When the excavation
has proceeded a little way, she begins to spin the lining which
forms the dwelling. I conclude thus, because nests are occasionally
found a few inches in length, with the lid and upper part perfect,
but without any bottom, these being evidently in the course of
formation. I suppose that she weaves her silk at first in unconnected
patches, against the earthy sides, perhaps where the mould is liable
to fall in; and thus I account for the loose rough laminæ of silk
that are always found projecting from the outer surface. These are
overlaid with other patches more and more extensive, until the whole
interior walls are covered; after which the silk is spun evenly and
continuously all round the interior, in successive layers of very
dense texture, though thin. Under the microscope, with a power of 220
diameters, these layers are resolved into threads laid across each
other and intertwined in a very irregular manner; some are simple,
varying from 1/7000 to 1/2000 of an inch in diameter, and others are
compound, several threads, in one part separate, being united into
one of greater thickness which cannot then be resolved.... The mouth
of the tube is commonly dilated a little, so as to form a slightly
recurved brim or lip; and the lid is sometimes a little convex
internally, so as to fall more accurately into the mouth and close it.
"The thickening of the hinge by additional layers is, I think,
accidental only, as, out of the many specimens that I have examined,
only one or two had such a structure. In the neatest examples, the
lid is of equal thickness throughout its extent, agreeing also with
the walls for the first few inches of their depth."
Mr. Gosse says that he possesses one specimen of peculiar
compactness, which differs from all the others that he has examined
in having "a row of minute holes, such as might be made by a very
fine needle, pierced around the free edge of the lid, and a double
row of similar ones just within the margin of the tube. There are
about fifteen or sixteen punctures in each series, and they penetrate
through the whole substance, the light being clearly seen through
each hole. I do not think, as I have somewhere seen suggested, that
they are intended to afford a hold for the spider's claws when she
would keep her door shut against the efforts of an enemy, for what
would be the use of having them in the tube _close to the lid_, so
close that not the eighth of an inch intervenes between the surface
of the lid and that of the tube, when the former is tightly closed? I
would suggest whether they may not be air-holes, for so tight is the
fitting of the lid, and so compact the texture of the material, that
I should suppose the interior would be impermeable to air but for
this contrivance."[56] "The spider that inhabits this nest is black,
with the thorax of an exceedingly lustrous polish, its abdomen is
full and round, its legs very short."
[Footnote 56: I cannot myself think this explanation probable, and
should still be inclined to consider these punctures to be the claw
marks of the spider, as is the case in some European nests.]
Another form of this single door wafer nest is described by Mr.
Sells,[57] in which there is a hinge-like thickening of the silk
lining of the tube about an inch below the actual hinge of the door,
which it is suggested may serve to give additional elasticity.
This was not found, however, in all the nests examined, and Mr.
Sells conjectures that in newly constructed nests the lid may close
sufficiently firmly without this contrivance, and that it is only
added in older nests.
[Footnote 57: Mr. W. Sells. Notes respecting the Nest of _Cteniza
nidulans_, in Trans. Ent. Soc. ii. 207-210.]
Patrick Browne's figure, to which reference has been made above,
represents a nest with two doors, one applied against the other, at
the mouth of the tube, and it has often been asked what this could
possibly mean.
Some have thought that the drawing was fanciful, others that it was
made from an abnormal or injured nest. However, I believe that the
drawing, though rude, is, in fact, not very incorrect, and shows a
case of repair or enlargement of the nest, a subject to be treated of
more fully further on. There is a specimen exhibited in the British
Museum which in this respect very nearly corresponds with Browne's
figure; it is labelled "Nest of Trap-door Spider with two doors,
from the spider having enlarged its abode.--Jamaica." Here one sees
that the spider has prolonged its tube about half an inch beyond the
original mouth of the nest, where it has constructed a new mouth and
door, the old door standing straight up at the back of and behind the
new one.
I imagine that the explanation of this curious piece of cobbling may
be somewhat as follows:--When the nest was in its original state and
had but one door, this door became by some accident covered over with
earth to about the depth of half an inch, and the inmate was thus
imprisoned. Then the spider, being, like most other members of its
order, very unwilling to abandon its home, determined to clear away
the entrance to its nest, and to lengthen the tube so that it should
reach up to the new level of the surface of the earth.... If I am
right, this should rather be called a lengthening than an enlargement
of the tube.
The nests of the cork type (A, p. 79) may usually be distinguished
at a glance from those of the wafer type by the greater thickness
of the door, and by its manner of shutting, but a nest from Morocco
has been figured and described by Prof. Westwood,[58] which seems
intermediate between the two. The door in this case may perhaps be
considered as of the cork type, though it is very thin, for it does
fit into the mouth of the tube, which is bevelled to receive it.
[Footnote 58: Observations on the Species of Trap-door Spiders, in
Trans. of Entomological Soc., London, 1841-3, vol. iii. p. 175.
I wish to take the present opportunity of thanking Prof. Westwood for
having afforded me special facilities for examining this and other
specimens forming part of the very valuable collections under his
care at Oxford.]
These nests were forwarded with their living occupants (_Cteniza
[Actinopus] ædificatorius_) from Tangiers to Prof. Westwood, who
describes the nests as being "about four inches deep, slightly curved
within, about three quarters of an inch in diameter, the valve at the
mouth not being circular, but rather of an oval form, one side where
the hinge is placed being straighter than the other. The valve is
formed of a number of layers of coarse silk, in the upper layers of
which are imbedded particles of the earth, so as to give the cover
the exact appearance of the surrounding soil, the several successive
layers causing it, when more closely inspected, to resemble a small
flattened oyster-shell."
The resemblance between this nest and that of the West Indian species
is the more interesting as Prof. Westwood says that both belong to
the same genus, (_Cteniza_ or _Actinopus_ of different authors,)
and are so closely allied as to present scarcely any important
distinction but that of size.
We shall find, however, on comparing the nests of these trap-door
spiders and their occupants, that we cannot as yet make any rule as
to the kind of nest which we may expect from a given spider.
It will be seen that species belonging to the same genus, and closely
resembling one another, sometimes build dissimilar nests; while
others, belonging to different genera, and unlike in many important
respects, construct almost identical nests.
This is the more strange, because, if we examine the structure of the
claws and palpi, they often seem to be specially adapted to serve as
carding instruments and to play a very important part in the weaving
of the silk linings of the nest; and yet nests of the same type are
occasionally produced by spiders in which these appendages are quite
unlike, and dissimilar nests where the claws and palpi are to all
appearance identical.
Thus, for example, if the reader will examine the drawings of part
of the foremost right foot of _Cteniza fodiens_, figs. A, 9 and 10,
Plate VII., p. 88, with that of _Nemesia cæmentaria_, figs. A, 9 and
10, Plate VIII., p. 94, both of which make nests of the cork type,
he will see that in the former the last joint of the tarsus is armed
along the inner side, with many moveable spines, and that each of the
two curved terminal claws has only one very strong tooth near the
base; while the same joint of the latter (_N. cæmentaria_) has no
spines, and the claws have three minute comb-like teeth near the base.
On the other hand, in the reverse case, where the structure of the
same joint is very similar, the nests may be wholly unlike, as in
_Nemesia Eleanora_, Plate XII., p. 106, and _N. cæmentaria_, Plate
VIII., where the nest of the former is of the double-door unbranched
type, and that of the latter of the single-door cork type.
It is probable however that a fuller and closer comparison of, and a
more exact acquaintance with the several parts and their functions
might show us that all spiders which spin similar webs are furnished
with equivalent instruments, so that what one leg lacks another may
possess in some shape or another; brushes of stiff hairs in one
place, compensating for a toothed claw, or for a row of moveable
spines in another.[59]
[Footnote 59: The claws are probably of first-rate importance in this
respect and should be most carefully studied. M. Lucas has stated
that the claws of _Mygale Blondii_, and _M. nigra_ from Algiers, and
of _M. nigra_ and _M. avicularia_ from Brazil, are retractile like
those of a cat! Unfortunately the dwellings of these spiders have
not been described. See Lucas (H.) in Rev. et Mag. de Zoologie, sér.
2, tom. ix. 1857, p. 587, and Ann. de la Soc. Entom. de France, ser.
3, tom. v. p. cxx., and vi. p. clxxi. Another curious point in which
spiders differ is the presence or absence of viscidity in the hairs
which clothe their feet and palpi. Mr. Blackwall states (Spiders of
Great Britain and Ireland, vol. i. p. 13), that by far the greater
number of the sub-order _Territelariæ_, or _Mygalidæ_ as he terms
them, "have the inferior surface of their biungulate tarsi, and of
the digital joint of their pediform palpi, in the females, densely
clothed with compound, hair-like papillæ, constituting an apparatus
which, by the emission of a viscous secretion, enables them to
traverse the perpendicular surfaces of dry, highly polished bodies;
others have three pairs of spinners and are destitute of hair-like
papillæ on the legs and palpi."
The four species of trap-door spider on the Riviera, here described,
appear to form exceptions to this rule, however, for they all
remained helpless prisoners when placed in a glass tumbler, though
struggling vigorously for freedom.
When, however relying on this experience, I placed a number of
smaller spiders of different kinds in glasses for examination some
walked straight out without any difficulty, while others were unable
to climb up the sides.]
It would be interesting, from this point of view, to draw all the
parts which may be supposed to aid in the act of weaving, and so to
contrast the corresponding limbs of different spiders, the nests of
which are known, that one might see at a glance in what they differed
and agreed. I have done this for the falces and the last joint of
the foremost right foot of the four spiders figured in Plates VII.,
VIII., IX., and XII., but to make the case complete all the limbs
should be represented in the same way.
Of the two spiders which are shown with their cork nests in Plates
VII. and VIII., the purplish grey _Cteniza fodiens_, (Plate VII.)
appears to be much rarer than the brown striped _Nemesia cæmentaria_
(VIII.), at any rate at Mentone. I have hitherto only succeeded
in obtaining four specimens of the former, though I have searched
repeatedly for them at Cannes and Mentone, while the latter species
is tolerably common.
The nests are, however, often extremely hard to find, and in some
cases it is only by chance that I have been able to light upon them.
All these trap-door spiders seem usually to prefer rather moist
and shady places, and sloping banks or loose terrace walls where
the interstices between the stones are filled up with earth, and
concealment is afforded by the creeping lycopodium (_Selaginella
denticulata_), Ceterach, spleen-wort or maiden-hair ferns, with short
moss and splashes of white lichen to distract the eye.
It was from such a terrace wall at Mentone, on March 26, 1872, that
the nest A in Plate VII. was taken, the tube running obliquely back
into the earth between the stones, and the door being concealed by a
net-work of lycopodium, one spray of which had been allowed to grow
on its upper surface.
The tubes of these as of the other kinds of nest are sometimes
straight, but more frequently they are bent, and almost always take a
downward course.
The following is Mr. Pickard-Cambridge's description[60] of _Cteniza
fodiens_, the spider which constructs this nest.
[Footnote 60: The following description and remarks, printed in a
different type, have been kindly prepared for this work by the Rev.
O. Pickard-Cambridge, to whom I sent a series of specimens of the
spiders preserved in spirit of wine and their nests. My very sincere
thanks are due to Mr. Pickard-Cambridge for this assistance, which
will give to my publication a value in the eyes of Arachnologists
which it could not otherwise have possessed. To all those who wish
to study the true structural relations of the four spiders, the
habits of which are recorded in the following pages, these details
will prove of the highest importance; while those who are only
interested in the economy of these creatures can readily pass them
over. For observers in the field there is a very ready way of knowing
these four spiders apart, as it will be seen that when they are
somewhat alike the nests are different (_Nemesia meridionalis_ and
_N. Eleanora_), and when the nests are alike (_Cteniza fodiens_ and
_Nemesia cæmentaria_) the spiders are markedly dissimilar.]
[Illustration: _Plate VI._]
FAM. THERAPHOSIDES.
Gen. Cteniza, Latr.
Cteniza fodiens. Plate VII.
Syn. _Mygale fodiens_, Walck. _Ins. Apt._, i. p. 237.
_M. Sauvagei_, Ausserer, _Beiträge zur Kenntniss der Arachniden
Familie der Territelariæ (Thor.)_, p. 36.
Female adult length 10 lines.
_Cephalothorax_ oblong oval, somewhat truncate at each end, and of
a dull whitish-yellow brown colour, the normal grooves and furrows
are strongly marked, the caput is large and elevated, rounded on
the sides and slightly higher near the occiput than at the ocular
area, the junction of the thoracic segments is indicated by a
strong deep curved indentation, the curve directed backwards;
there are a few strong black bristles of different lengths within
the ocular space, and several others run backwards in the central
line to the occiput. The height of the Clypeus is equal to rather
more than the diameter of one of the foremost eyes. The _Eyes_ are
eight, and form a rectangular figure whose transverse diameter
is the longest, and whose fore side is a little shorter than
the hinder one; the longitudinal diameter is about equal to the
space between the two foremost eyes; these are the largest of the
eight, and are separated by an interval of very nearly two eyes'
diameters; the two central eyes are the smallest, and are distant
from each other just about one eye's diameter, the eyes of the
hinder row are in two pairs forming the hinder corners of the
rectangle, those of each pair are nearly contiguous to each other,
and the inner one of each is the smallest; these last in the figure
appear to be the smallest of the eight, but this arises from the
point of view whence the figure was drawn; the two central eyes
occupy as nearly as possible the centre of the figure formed by the
two foremost eyes, and the two inner ones of the hinder row, and
are seated on a large black spot. The _Legs_ are short, strong,
and similar to the Cephalothorax in colour, their relative length
appeared to be 4, 3, 1, 2, they are furnished with hairs, bristles,
and short strong spines. These latter are on those of the two first
pairs, situated chiefly in two longitudinal parallel rows beneath
the tibiæ, metatarsi, and tarsi; on those of the third pair they
are situated on the sides and upper sides of those joints, while
the fourth pair has them only beneath the metatarsi and tarsi; all
the tarsi terminate with three claws, the two superior ones are
much the longest and strongest, and have a single short strong
tooth inside near the base. Near the union of the femora and genuæ
of the legs of the fourth pair are numerous short strong spines,
hairs, and bristles. The _Palpi_ are similar in colour to the
legs; they are strong and about equal in length to the legs of the
second pair, and have a double longitudinal row of strong spines
widely separated and divergent from each other beneath them; the
digital joint (like the tarsi of the legs) is furnished with other
spines between these two rows; each palpus terminates with a single
untoothed curved claw. The _Falces_ are strong, prominent, rounded
in the profile line, and have some hairs, bristles, and spines near
their fore extremities; the longest and strongest of the spines
are three in number, and form a kind of transverse row or comb at
the extreme inner point on the upper side of each falx; besides
these there is a row of short tooth-like spines on either margin of
the furrow on the under side of each falx in which the fang lies
concealed when at rest. The _Maxillæ_ are short and strong; the
palpi issue from their extremity on the outer side, and the inner
extremity is somewhat prominent and pointed.
The _Labium_ is small, short, somewhat rectangular in form, and
broader than high; the apex is a little rounded, and furnished with
a single transverse row of small tooth-like spines.
The _Sternum_ is somewhat subtriangular in form, much broader
behind, where it is rounded on the outer angles.
The _Abdomen_ is short oval, very convex above, where it is of a
yellowish vinous brown colour, with a slightly darker longitudinal
tapering, indistinct central stripe on the fore part; it is
sparingly clothed with hairs, and the under side is of a pale dull
yellowish colour; the spinners are four in number, and those of the
superior pair are the strongest, three jointed and upturned.
Adults and immature examples (all females) were found in tubular
holes lined with silk and closed at the orifice with a strong solid
hinged lid, shutting into the opening like a cork.
The portions of nests at B and C in Plate VII. also belong to
_Cteniza fodiens_, the latter being very similar to A in its
surroundings, but having a rather thinner door, slightly hollowed out
above (C 1). The smaller nest shown shut at B and open at B 1,[61]
is admirably concealed by mosses and lichens, some of which actually
grow upon the door, and here two minute trap-doors, belonging
to infantine examples of a distinct species of spider (_Nemesia
meridionalis_), are seen on the left hand below.
[Footnote 61: It must be clearly understood that when the doors are
represented as standing open or ajar this is unnatural, as they
always close by their own combined weight and elasticity.]
It is not rare to find small colonies of nests of the same or
distinct species grouped closely together in this way, though I
greatly doubt whether one can safely assume their sociability from
this fact.
I have very seldom seen nests on the flat ground, where the door
would lie horizontally when closed, a sloping or nearly vertical bank
being usually chosen, where the door will fall to by its own weight.
In the Ionian Islands another species or variety of _Cteniza_,
described under the name of _Cteniza (or Mygale) ionica_, and
represented as being of an uniform yellow-brown colour, is said to
make its nests in the earth of the terraces round the roots of the
olive trees.
Mr. Saunders[62] gives admirable figures and descriptions which show
us at once that these nests, which he discovered in rather elevated
situations in the island of Zante, are of the cork type; but, in
this case, the entire door does not shut flush with the surface, as
in ordinary cork nests, but has a short spur-like projection above
and behind the hinge, serving, as is conjectured, like a lever, by
pressing on which from the outside the lid may easily be raised.[63]
When I come to speak of the manner of constructing and repairing
nests I shall have occasion to refer to these nests again.
[Footnote 62: Sydney Smith Saunders. Description of a Species of
Mygale from Ionia, in Trans. Ent. Soc. London, 1839, vol. iii. p.
160, Plate IX.]
[Footnote 63: I must own to some hesitation about accepting this
explanation, though I am not prepared to offer any other.]
I have not as yet found any nests on the Riviera which can be said to
correspond accurately with those of _Ct. ionica_, the only builders
of cork nests yet discovered in this district being _Cteniza fodiens_
and _Nemesia cæmentaria_.
This latter species is described by Mr. Pickard-Cambridge,[64] in the
following terms:--
[Footnote 64: See above, p. 88.]
Gen. Nemesia (Savigny).
Nemesia cæmentaria. Plate IX.
Syn. _Mygale cæmentaria_ (Latr.), _H. N. des Crust._ t. vii. p. 164.
_M. cæmentaria_ (Walck), _Ins. Apt._ i. p. 135.
Female adult, length 9 to 11 lines.
_Cephalothorax_ rather elongate, oval, and somewhat truncated at
each extremity; the caput is elevated and rounded on the sides and
upper part, but less elevated than in _Cteniza_; the normal grooves
and indentations are well marked, and the junction of the cephalic
and thoracic segments is indicated by a strong deep impression or
cleft, of a transverse, curved, or somewhat bent angular form, the
curve or angle directed forwards. The colour of the cephalothorax
is yellow-brown tinged with olive, the margins are paler, but
have no distinctly defined marginal band. On the hinder part of
the caput are three clear brown-yellow longitudinal stripes; the
central one reaches from behind the two hind central eyes to the
thoracic junction, the lateral ones converge a little to the same
point, but do not reach nearly, in fact not much more than half
way, to the eyes. The clypeus is of a clear brown-yellow colour
also, and on either side of it (extending from each fore lateral
eye), is an irregular patch of the same. The ocular region and
clypeus are furnished with a few strongish black bristles, and the
three yellow stripes above mentioned have a few more, those on the
central stripe being the longest and strongest, and disposed in a
single longitudinal row.
The _Eyes_, eight in number, are seated on a transverse oval
eminence, and form a rectangular figure, whose transverse diameter
is double the length of its longitudinal diameter: their relative
position is similar to that of _Cteniza_, but in the present
species they are smaller than in _C. fodiens_: those of the hind
central pair are the smallest of the eight, and each is very
nearly contiguous to the hind lateral on its side; the interval
between those of each lateral pair is small; the space between
the two central eyes of the eight is equal to an eye's diameter,
and each of these is separated from the hind central and fore
lateral nearest to it by a similar interval. The _Legs_ are strong,
moderately long, their relative length 4, 1, 3, 2?, but little
difference is observable between 1, 3, and 2; they are furnished
with hairs, bristles, and a few, not very strong, spines; each
tarsus terminates with three curved claws, the two superior ones
much the longest and strongest, and have a few small teeth near
their base inside.
The _Palpi_ are strong and similar in colour and armature to the
legs; each is terminated with a curved black claw.
_Falces_ strong, prominent, and rounded in the profile line;
they are furnished with hairs, bristles, and strong tooth-like
spines; the four strongest of these latter form a transverse row
at the inner extremity of each; besides these there is a row of
short tooth-like spines on the inner margin of the furrow on the
underside of each falx, in which the fang lies concealed when at
rest. The _Maxillæ_ are strong, with a small angular prominence at
their inner extremities (when looked at from beneath), and each
has three to four small dark-coloured teeth in a short, straight,
obliquely transverse row at the base on the inner side. _Labium_
broad but short, its breadth is double its height, and the upper
corners are rounded off. The _Sternum_ is of a somewhat pentagonal
form.
_Abdomen_ rather elongate oval, tolerably, but not excessively,
convex above; it is of a dull yellowish whitey-brown colour marked
and mottled above with dark chestnut brown; the markings are rather
irregular, but a general disposition in the form of a longitudinal
central, and oblique lateral, stripes or bars may be traced on the
hinder half; the superior spinners are short and three-jointed,
those of the inferior pair are exceedingly minute.
Adult females were found in nests similar to those of _Cteniza
fodiens_.
The cork nests are the simplest form of nest, with the exception of
those described above from Jamaica, and have constituted, up to the
present time, the only type known in Europe. Their chief claims to
our admiration lie in the perfection of workmanship which the doors
usually exhibit, and the marvellous concealment which they afford
when closed. These doors as a rule fit so tightly [thanks to the
accurate adjustment of their sloping sides to the bevelled lip of
the tube which receives them,] that they afford a certain amount
of mechanical resistance, even when the spider is away. But, after
examining a very large series of these cork nests, I find that there
is some variation in the degree of perfection attained in their work
by different individuals of the same kind. The mechanical resistance
is greater or less in proportion to the thickness and weight of the
door, and to the slope of its sides, and of the bevelled edges of
the tube; and in each of these details a marked difference may be
observed.
One might suppose from what has so often been repeated as to the
habits of _N. cæmentaria_, that, whenever any one attempts to open
the door, the spider, which is always at home in the day time, would
dart up from the bottom of the tube and endeavour to keep it closed
by holding on from within.
[Illustration: _Plate VIII._]
I cannot say what may take place during the summer months; but from
October to May I have but rarely found one of these spiders ready to
oppose me, though _Nemesia meridionalis_ and _N. Eleanora_ frequently
did so. Many times, wishing to provoke them, I have tapped at the
door in order to apprise the occupant of my arrival, or lifted it and
let it fall again, and always in vain, though the spider was there,
crouching at the bottom of her tube.
Indeed I can only recall six or eight instances in which this spider
did hold down her door, and on three of these she was captured.
I will now relate what I saw on one of these occasions,[65] for there
has been much speculation as to the manner in which the spider clings
to the door and offers the determined resistance which is experienced.
[Footnote 65: Mrs. Boyle was the first to witness this curious sight,
and my description of the resistance of the spider is almost an exact
repetition of hers to me. It is curious also that, following her
indications, I found the very nest and spider on which she had made
her observations, and every detail recurred again though several days
had elapsed between her visit and mine.]
No sooner had I gently touched the door with the point of a penknife
than it was drawn slowly downwards, with a movement which reminded
me of the tightening of a limpet on a sea-rock, so that the crown
which at first projected a little way above, finally lay a little
below the surface of the soil. I then contrived to raise the door
very gradually, despite the strenuous efforts of the occupant, till
at length I was just able to see into the nest, and to distinguish
the spider holding on to the door with all her might, lying back
downwards, with her fangs and all her claws driven into the silk
lining of the under surface of the door. The body of the spider was
placed across, and filled up, the tube, the head being away from
the hinge, and she obtained an additional purchase in this way by
blocking up the entrance.
I did not force the spider to release her hold, but, by a rapid
stroke with a long-bladed knife, cut out the upper part of the tube
with the surrounding mass of soil, and thus secured the trap-door and
its owner. This specimen is represented at fig. C, Plate VIII., where
the pin-point holes made by the claws may be seen in pairs round the
whole circumference of the flatter portion of the lower surface of
the door except on the side next to the hinge.
Whenever a spider resists in this way she must make these holes, but
I have very rarely seen them in other nests; this may perhaps be
accounted for by their having been effaced by the action of moisture
which would stretch the silk. However this may be, this specimen
showed the claw marks quite distinctly on my return to England after
the lapse of several weeks.
Much has been written about these marks, which are frequently spoken
of as holes purposely made in the silk in order to give the spider a
better purchase. It has also been stated that two holes may be seen
in the silk of the tube near the mouth on the side away from the
hinge, but these I have never been able to find. The door of nest A
in Plate VIII. is rather abnormal, as it is made up of two doors, the
smaller one being spun into the top of the one now in use. This is,
I believe, an abnormal and rather clumsy example of the ordinary way
of enlarging the nest, but of this we shall see more when we come to
speak of the construction and repairing of these nests generally.
Fig. B in this plate represents a moss-covered sod pierced by the
tube of a nest, the door of which is entirely concealed from view,
and only discovered when opened as at B 1.
This nest was found accidentally by Mr. Robert Lightbody, who
kindly brought it to me, its presence having been betrayed by the
tube, which he happened to cut through in digging up a plant. The
moss on the door grew as vigorously, and had in every way the same
appearance, as that which was rooted in the surrounding earth; and so
perfect was the deception that I found it impossible to detect the
position of the closed trap even when holding it in my hand. There
can be no doubt that many nests escape observation in this way, and
the artifice is the more surprising because there is strong reason to
believe that this beautiful door-garden is deliberately planted with
moss by the spider, and not the effect of a mere chance growth. I
shall adduce evidence in support of this statement by-and-by.
I alluded to the nest C (Plate VIII.) when speaking of the claw
marks which it exhibits, and that figured at D and D 1 in this plate
is merely an instance of a good example of this type. I have taken
nests of _N. cæmentaria_ both at Cannes and Mentone, and have little
doubt that this species will be discovered at many points along the
Riviera. I detected two abandoned nests of the cork type, which I
fully expect had belonged to _N. cæmentaria_, in an enclosed space
called the Campagne de Garonne in Marseilles itself. These nests lay
in the little mound of undisturbed earth between the divided trunks
of the small olive-trees, and I do not doubt that if I had had time
to search I should have discovered more nests, and perhaps others
which were still tenanted.
We now turn from the single-door nests to those with double doors,
and from the well known to the new types of structure.
In these we have a thin and wafer-like door at the mouth of the
nest, and from two to four inches lower down, a second and solid
underground door. These lower doors are characteristic of the
nests to which they belong, that of the branched nest (_Nemesia
meridionalis_, Plate IX.) being long and more or less tongue-shaped,
while that of the unbranched double-door nest (_N. Eleanora_, Plate
XII. p. 106) is somewhat horse-shoe shaped.
The surface doors of these two kinds of nest do not appear to
differ, and, though rather thinner, may be compared to those of the
single-door wafer kind from Jamaica.
The commonest form at Mentone is the branched nest, which may be
found in abundance in many of the loosely-built walls of the lemon
and olive terraces or on sloping banks, but they are rarely to be met
with on flat ground.
In the nests of _Nemesia meridionalis_ the tube, instead of being
simple, as it is in all other known nests, is invariably branched,
a second tube joining the first at the point where the lower door
is hung and forming with it an angle of about 45°. The main tube
descends and is frequently curved, or sometimes doubly bent like the
spout of a tea-kettle (A, Plate X. p. 100), while the branch ascends,
and in some few instances reaches the surface, though it is usually a
_cul de sac_ (Plate IX.)
[Illustration: _Plate IX._]
In the exceptional cases where the nests have two superficial
openings, one of the two surface doors always appears neglected and
going to decay, or is covered with earth which chokes the upper part
of its tube. The explanation of this probably is that the spider
found the original entrance blocked up or in some way unfitted for
use, and then prolonged what was the blind branch until it reached
the surface and replaced the former doorway. However this may be it
is certain that in the great majority of nests it will be found that
the branch ends in the earth, and is a _cul de sac_, and this I have
invariably observed to be the case in the nests of very young spiders
of this species (fig. B, Plate IX.)
The tube is frequently enlarged at the mouth, and forms a spreading
lip which the surface door is usually large enough to cover (A 1,
Plate IX.)
In these branched double-door nests the upper door does not fit into,
but merely lies upon, the mouth of the tube, the elasticity of the
hinge and its own weight being sufficient to keep it closed. The
lower door is suspended by a hinge placed at the apex of the angle
formed by the bifurcation of the tube, and is hung in such a manner
that it can either be pushed upwards so as to lie diagonally across
and block the main tube, or be drawn back so as to fit into and close
the entrance to the branch.
This will, I think, best be understood by reference to the drawings
of a small nest of this type given at B 1 and B 2 in Plate XI. p.
105, where the second door is shown in its two positions. This lower
door is from 1 to 1-1/2 lines thick, channeled above, but nearly
flat on the back, and of an elliptic form, with a loose appendage
at its lower end, the whole being made of earth enclosed in a case
of silk.[66] When the lower door is drawn back so as to close and
conceal the entrance to the branch, it lies in the same plane, and
closely corresponds in curvature with the lining of the main tube and
almost appears to form part of it (fig. A, Plate X. p. 100, and fig.
B 1, Plate XI. p. 105).
[Footnote 66: Since writing the above I have learned, thanks to a
better method which I have recently adopted for preserving the nests
for examination, that sometimes the lower door, instead of being free
within the tube and only attached to the lining by the hinge, is
surrounded on either side by a delicate silk web, which extends from
either edge of its lower surface to the silk walls of the tube below
and forms a sort of double gusset. This admits of the movement of the
lower door in the way described above, but perhaps serves, together
with the solid appendage at the extremity of the free end of the door
(that away from the hinge), to prevent the door from being driven too
far in an upward direction and thus becoming so tightly jammed as to
make the spider a prisoner in her own nest. I think it possible that
the lower door is always attached to the tube in this way, but, as
it parts readily from the silk on either side when the earth which
supports the tube is removed, it very frequently appears to be free,
as I have represented it in Plates IX., X., and XI.]
When digging out these nests, after carefully removing the upper
portion, I have frequently seen the lower door move across and block
up the main tube in a mysterious manner, it being in reality pushed
by the spider from below, and she may sometimes be captured at her
post with her back set against the door. More frequently, when the
spider finds that resistance is hopeless and sees the earth crumbling
in, she drops to the bottom of her nest and lies there helpless, with
her legs folded against her body like an embryonic creature; some,
however, more savage than their neighbours, fly out and strike at the
intruder with their fangs.
[Illustration: _Plate X._]
What then, it may be asked, is the use of the branch? I do not think
that we can draw any safe conclusion from what takes place when we
dig out a spider, as to what would occur if she were besieged by one
of her natural enemies, such as ichneumons, sand-wasps, centipedes
(_Scolopendra_), small lizards &c.[67]
[Footnote 67: For some account of the principal enemies of spiders
generally, see p. 134.]
Let us suppose, however, that one of these creatures has found
its way into the nest and is crawling down the tube. What will
probably happen? Why, in the first place, the spider will slam the
second door in the face of the intruder, and then, if worsted in
the pushing match which follows, quickly draw this door back again
and run up into the safety branch, when the enemy, after descending
precipitately to the bottom of the main tube, will look in vain for
the spider as it searches on its way up for the secret passage now
closed by its trap-door. This is but a purely imaginary case, and it
may be that the branch has some wholly different purpose.
It seems very improbable, however, that it should be mainly intended
as a safety place for the eggs or offspring; at least if this were
the case we should not expect to find it, as we do, in the nests of
very young spiders (fig. B, Plate IX.), which could have no use for
it.
The large spider and its nest figured at A and A 3 in Plate
IX. were taken at Mentone on March 17, 1872, and the following
is the technical description of the species, written by Mr.
Pickard-Cambridge:--
Nemesia Meridionalis. Plate IX.
Syn. _Mygale meridionalis_ (Costa). _Fauna del Regno di Napoli_, p.
14, Pl. I., figs. 1-4, ad partem.
Female adult, length 11 to 13 lines.
This spider is very nearly allied to _N. cæmentaria_ both in
general structure and colours, but it may be distinguished by
the more elongate form both of the cephalothorax and abdomen;
the colours also of the present species are more distinctly
distributed; a well-defined narrow marginal band, irregular on
the inside, surrounds the thorax; and the caput has a large
curved patch of the same on either side of the ocular area,
with a broad tapering band tinged with orange, which runs from
immediately behind the eyes to the thoracic junction, where it
ends in a point. The transverse diameter of the ocular area is
also less in proportion to its longitudinal diameter than in _N.
cæmentaria_, and the eyes are all smaller, but placed on a similar
oval eminence, and several bristles are directed forwards from
the middle of the lower margin of the clypeus, while one or two
others are found in the ocular area, and three or four more (long,
strong, and nearly erect) form a longitudinal row along the middle
of the central tapering thoracic band. The _Falces_ are deeply
yellow-brown, with two to three elongate oval patches or short
longitudinal parallel bands on their upper sides; in their armature
the falces are similar to those of _N. cæmentaria_. The _Labium_
appeared to be less broad in proportion to its height, and the
_Sternum_ smaller and of a more oval form than in that species. The
_Abdomen_ is similarly marked, though the chocolate-brown markings
appeared to be less deep and dense, being more broken up, but still
forming several fairly defined, bold, and broad angular bars or
chevrons on the upper side. The inferior spinners, though small
(like most of the corresponding pair in species of this family),
are yet considerably stronger than in _N. cæmentaria_.
Adult females of this spider were found in tubular silk-lined
holes in the earth, closed at the external orifice with a flat
scale-like hinged lid, covered with lichens and mosses. Not quite
half way down this tube is a tubular branch running off upwards
at an angle of 45° or less; the main tube also at this point is
furnished with an elliptical-hinged valve, with which the spider
appears to have the power to close the entrance to the branch or
to shut off the upper part of the main tube. This branch (found
also in the tubes of very young examples) seems to be certainly
a strong distinguishing character in the economy of the species,
and separates it at once from _N. cæmentaria_. In the nest of _N.
meridionalis_ the tube also projects at times above the surface
of the soil upwards among the herbage which serves to conceal it.
Costa appears to have had before him this latter species as well as
what is here taken as the typical _N. meridionalis_, as he speaks
of the nests under his observation as being frequently branched,
while his description would suit both species; his figure, however,
more nearly agrees in the thoracic pattern with the spider above
described. Ausserer, in his elaborate paper on the Mygalides,
lately published (_Beiträge_ &c. vide supra), appears to have
overlooked _M. meridionalis_ (Costa) altogether; while Canestrini
and Pavesi (_Catal. degli Araneidi italiani_ in _Atti Soc. Ital.
Sc. Nat._ xi. (1869)), p. 25, include it under the synonyms of _M.
fodiens_ Walck., from which it is undoubtedly distinct, as may be
seen at once, even if it were only by the difference in the form
and structure of the lid with which the external orifice of the
tubular nest is closed.
In the case of the upper door of these branched nests, as there
is but a very thin coating of earth on their upper surface, it is
rare to find any of the larger mosses or lichens growing upon them;
but, as if to compensate for this deficiency, a variety of foreign
materials are employed which are scarcely ever found in cork doors,
such as dead leaves, bits of stick, roots, straw of grasses, &c., and
I have even seen freshly-cut green leaves, apparently gathered for
the purpose, spun into a door which had recently been constructed.
But here again there is the widest possible difference between nest
and nest in the degree of perfection in their concealment; and,
although as a rule the surface of the upper door harmonizes well with
the general appearance of its surroundings, there are some individual
nests in which it readily catches the eye and even attracts attention.
Thus, I have seen nests in mossy banks where the doors, being made
of nothing but earth and silk, showed distinctly as brown patches
against the green; and those doors which are covered with earth only,
even when they are surrounded by earth, are often easily detected,
because when they dry up, as they quickly do, they become much paler
in colour than the earth of the bank, which retains its moisture.
Perhaps in no case is the concealment more complete than when dead
leaves are employed to cover the door. In some cases a single
withered olive leaf only is spun in and suffices to cover the trap;
in others, several are woven together with bits of wood and roots, as
in the accompanying woodcut, which represents different views of the
upper door of the nest which is drawn in Plate X. p. 100.
[Illustration]
[Illustration: _Plate XI._]
In this nest another interesting feature presents itself, for here
the tube projects a short way beyond the surface of the ground and
is hardened and coated with earth and fine gravel in such a way that
it requires no other support. This is not commonly the case, and may
perhaps be the result of a contrivance to meet the necessities of
a nest which has had the surface earth washed away from it. But I
have frequently observed nests in which the upper part of the tube
is carried up for two or three inches through grass, moss, ferns,
pellitory, or the like, the stems of the sheltering plants being
interwoven with and made to support the tube.[68] In every case
the second door, which is designed for resistance and requires a
firm-walled tube into which it may be wedged, is below ground, and
for the same reason we scarcely ever find cork nests constructed with
any part of the tube projecting beyond the surface of the soil.
[Footnote 68: This aërial portion of the tube corresponds with that
of _Atypus piceus_ described above (p. 78), but differs in having its
aperture closed by a door.]
At fig. A, Plate XI., one of these branched nests is seen concealed
in a plant of ceterach fern, and here the tube is raised a short way
above the soil; while in fig. B of the same plate the common form is
represented, the upper door lying flat on the surface of the ground,
from which, thanks to its covering of small mosses, it is scarcely to
be distinguished.
The figs. B 1 and B 2 show this door open and the lower door in its
two positions.
Now that attention has been drawn to the existence of this new type
of nest, I fully expect that _Nemesia meridionalis_ will be found at
many points along the Riviera and in the whole Mediterranean region,
but I have hitherto only discovered it at Mentone and Cannes. Mrs.
Boyle saw one of these nests in the Pallavicini gardens near Genoa,
and there seems every reason to believe that certain nests which have
been detected near Naples and in Ischia, will, when better known, be
found to be of the branched double-door type.
It seems probable that our spider belongs to the species which
was first described by M. Costa,[69] under the name of _Mygale
meridionalis_, though, if we are to rely implicitly on the figures
and detailed account given by this naturalist, we must suppose that
it constructs a different nest in Southern Italy from that which it
makes on the Riviera, and one which, although it agrees in most other
respects, is destitute of the characteristic subterranean door.
[Footnote 69: Fauna del Regno di Napoli, (vol. containing _Animali
Articolati_, classe ii. Aracnidi: incomplete, Naples, 1861), p. 14,
tab. i. figs. 1-4. See Appendix A.]
It is more likely, however, that M. Costa has overlooked the
existence of the lower door, though it is strange that he should have
done so, as he says that the nests "sometimes have a double aperture,
and the upper portions of the burrows meet and anastomose at about
two inches distance," thus showing that he was aware that the tube is
branched.
One more nest only now remains to be described, and this is
again an example of a new type--namely, of that which I have
distinguished as the unbranched double door (Plate XII.), the work
of _Nemesia Eleanora_. This nest is never branched, and its second
and subterranean door is situated from one to four inches below
the surface door, and only serves to close the one tube which is
narrowed above the insertion of this lower door. Here, as in the
branched nest, the thin and wafer-like surface door appears to serve
principally for concealment and the lower one for resistance. This
latter, made out of earth encased in strong white silk, is from
one to two lines thick, and has, at the end away from the hinge, a
similar appendage to that found in the lower door of the branched
nest. This appendage serves, I imagine, as a kind of ear by which the
door, when firmly jammed into the tube on the approach of an enemy,
may be pulled down again as soon as the alarm is over. As in the
branched nest it has the upper surface concave and the lower slightly
rounded, so that when drawn back and not in use it may not obstruct
the passage. The sides of this lower door slope a little, so that
the crown is smaller than the base; and this is important, because
it causes the door to fit more tightly when driven upwards into the
tube, acting on the principle of an inverted cork door.
[Illustration: _Plate XII._]
In form this door is somewhat elliptic, but much broader and shorter
than the second door of the branched nest, and it is frequently of
a nearly horse-shoe shaped outline. The second door of the branched
nest is necessarily longer, having to perform the double function of
closing the opening to the branch and the passage of the main tube.
In either case, however, these doors will be found to be more or less
elliptic, and this is necessarily so, for, lying as they do when in
use in a plane which cuts the subcylindrical tube obliquely, they
have to fill a somewhat elliptical area.[70]
[Footnote 70: The lower door here, as in the branched nest (see
above, p. 100), is sometimes united to the silk of the tube below by
two nearly triangular gussets of silk, when, instead of being free
except at the hinge, as I have represented it (Plate XII.), it is
surrounded on either side by silk and only free at the extremity away
from the hinge. This does not, however, alter the function of this
door in any way.
It may be that these lower doors are always attached from below
in this way, but it is very difficult to be sure of this, as they
readily break away from the surrounding silk, when they appear quite
free, as in my drawing. It was not until I adopted the plan of
stuffing the tube full of cotton wool before removing the surrounding
earth that I detected this fragile attachment.]
I have observed some variation as to the exact proportions of these
doors, and it is quite possible that in many cases they are specially
adapted to meet peculiarities in the curvature of the tube.
The nest and spider drawn at figs. A and A 3 of Plate XII. were first
discovered by the Honourable Mrs. Richard Boyle at Mentone, on March
26th, 1872, and the following is the description of the species
kindly prepared by Mr. Pickard-Cambridge:--
Nemesia Eleanora, sp. nov. Plate XII.
Female adult, length 11 to 12 lines.
This spider, which has (like _N. meridionalis_) probably been
confused with its near ally _N. cæmentaria_, is yet easily
distinguished from both by its deeper and richer colouring, as well
as by other characters.
The _Abdomen_ has a far more spotted appearance; in some examples
a similar series of dark, broken, slightly angular bars is
indistinctly visible on the hinder half of the upper side; in
others (the more common type) the darker colouring preponderates,
and some transverse, broken, slightly angular, or nearly curved
bars or lines of pale spots constitute the pattern; the lateral
margins of the thorax are not so distinctly yellow as in _N.
meridionalis_, and there is a single longitudinal stripe on the
caput, of a dull orange-yellow brown, commencing directly behind
the eyes and tapering to the thoracic junction; the depression
or pit at this point is more strongly marked than in either of
the two foregoing species; the ocular area is also smaller, and
its transverse diameter is less in proportion to its width; the
bristles on the margin of the clypeus, as also those within the
ocular area and in the central longitudinal line of the caput, are
similarly disposed to those in _N. meridionalis_, but are more
numerous; in some details, however, of form and structure--viz.,
the Labium and Sternum--the present species is more nearly allied
to _N. meridionalis_ than to _N. cæmentaria_. The _Legs_ seemed
to be rather longer and stronger than in either; the tarsi and
metatarsi of the two first pairs, as well as the digital joints of
the palpi, are rather densely clothed a little underneath on their
outer sides with a kind of fringe or pad of close-set hairs; in
other respects the armature of the legs appeared to be similar to
that of the other two species, except that in the present one there
are three _short strong red-brown spines in a longitudinal row on
the outer sides of the genual joints of the third pair_; these
spines were plainly visible in all the examples found, but did not
exist in any one of those of the two former species. The armature
of the falces, which are of a uniform yellow-brown colour, is
similar to that of those species.
Adult females were found in tubular silk-lined unbranched holes,
closed at the orifice with a flat scale-like hinged lid concealed
by mosses and lichens, and having a horse-shoe shaped second valve
or door less than half way down the tube, of which it serves
to shut off the upper part. In this nest, as in that of _N.
meridionalis_, the upper part of the tube often projects above the
surface of the soil.
[Illustration: Nemesia Eleanora ♂ Adult, natural size.]
Since the above description of the female of this species was
written, an example of the adult male has been most opportunely
discovered. It is much smaller than the female, its length being
only six lines. The _Cephalothorax_ is of an uniform clear
yellow-brown colour, tinged with orange, and thinly clothed with
a greyish pubescence: the oblique indentations marking the union
of the cephalic and thoracic segments are indicated by a strongish
black-brown band on either side, which becomes obsolete as each
approaches the other near the central curved indentation; there
are also two or three converging suffused blackish stripes on the
hinder slope. The relative length of the _Legs_ is the same in both
sexes, 4, 1, 2, 3, but in the male those of the fourth are longer
in proportion to those of the third pair than in the female; the
spines also on the legs are more numerous and stronger, the upper
sides of the femora of all the legs are deeply suffused with black,
while in the female this suffusion is not nearly of so marked a
character, though the genua of the different females examined
had a strong brown-black macula on the outer side of each, while
the corresponding maculæ in the single male examined were but
just visible; the three spines observed on the outer side of the
genua of the third pair of legs in the female are of even a more
marked character in the male, and hence they may be considered a
good and tangible specific difference from other nearly allied
species; the tibiæ of the first pair are considerably enlarged on
the under side at the fore extremity, where each is armed with
a single, longish, strong, slightly curved, pointed black spine
directed forwards (fig. _a_, 3). The _Abdomen_ is small and of an
oval form; its colours and markings resemble those of the female,
but on the hinder half of the upper side two or three indistinctly
traced pale angular bars or chevrons are formed by the distribution
of the black-brown colours and markings; the under side of the
abdomen is of a uniform pale whitish yellow, except the spiracular
plates, which are yellow-brown. The _Palpi_ are moderately long
and strong; the radial joint is longer than the cubital, and is of
a tumid and somewhat oval form, suffused over most of its surface
with dark brown, the rest of the palpus being of a yellowish-brown
colour; the digital joint is small and somewhat oblong-oval, curved
downwards, and very slightly concave on its inside; the palpal
organs consist of a nearly globular, basal, corneous bulb prolonged
into a strongish, curved, but not very long, pear-stem form, the
stem being distinctly cleft or bifid at its extreme point (_vide_
figs. _a_ 1, and _a_ 2), one portion of the bifid part is larger
than the other, though both are equal in length, and the stem of
the palpal bulb is directed transversely outwards, almost at right
angles with the digital joint.
Until the discovery of the male spider now described, and which is,
without doubt, the male sex of the female described immediately
before, this latter was thought to be the female of _Nemesia
Manderstjernæ_ (Ausserer), and it had indeed been so determined
by Professor Ausserer himself. But the form of the palpal organs
differs so decidedly from those of _N. Manderstjernæ_ (Ausserer,
_Beiträge ... der Territelariæ, Verhandl. Z. B. Gesllsch_: Wien,
1871, Bd. xxi. p. 170), that all doubts as to the present being
a distinct (and as it is believed to be) a hitherto undescribed
species, are removed. From M. Ausserer's description, the
pear shaped stem of the palpal bulb in _N. Manderstjernæ_ is
comparatively slender, ending in a fine and uncleft point, whereas,
in _N. Eleanora_, the stem is strong and its extremity cleft: other
differences are also observable in the two spiders, but this one is
well marked and the most tangible.
The specific name, _Eleanora_, now conferred upon the species, is
taken from the Christian name of the Hon. Mrs. Boyle, reference
to whom has been before made, and of whose kind exertions some
acknowledgment is thus permanently recorded.
In fig. A, Plate XII., the upper door, which, if closed, would be
entirely hidden by the long filmy mosses which surround and cover it,
is represented open; but it should be clearly understood that this is
artificial and not natural, as in reality these doors close of their
own accord by means of their weight and the elasticity of the hinge.
It will be seen that living mosses of two kinds are worked into the
upper surface of this door, which was admirably concealed. (fig. A 1,
Plate XII.).
It is chiefly in the absence of the branch and the different form
of the lower door that the nest of _Nemesia Eleanora_ differs from
that of _N. meridionalis_; and, as they inhabit the same localities,
it is only when one has dug down as far as the lower door that it
can be known to which of the two species the nest belongs. When once
this point is reached however, all doubt is at an end; for in this
case the unbranched double-door nest differs from the branched in a
way which any child could realize, though the respective spiders are
not very dissimilar when seen with the naked eye alone. This affords
a good instance of the benefit which may accrue to a collector from
a study of the habits of the creatures which he collects, for it is
certain that it was the nest in this case which first proclaimed the
distinctness of its tenant.
_Nemesia Eleanora_ is rather less common at Mentone than _N.
meridionalis_, but at Cannes I found the reverse to be the case. At
the latter place, on the northern slope of the little hill of St.
Cassien, branched and unbranched double-door nests may, however, be
found in tolerable abundance, the traps being frequently concealed by
fallen leaves from the cork oaks, which are woven into their upper
surface.
The nest of _N. Eleanora_ often has the upper part of the tube
prolonged above the surface of the ground and carried up through
mosses, grasses, and the like.
An example of this is seen in figs. B and B 1, Plate XII., in which
the upper part of the tube is represented with the surface door open
in the one case and shut in the other.
The concealment here was so complete that I should never have
discovered the nest but for the merest accident. I happened to
want some moss to lay with flowers in my botanical tin, and in one
handful which I plucked up this trap-door lay concealed. It should be
observed that the upper part of the tube and its surface door were
covered with growing moss, and this moss must have lived exclusively
upon the moisture which the very damp and shady situation afforded,
as there was no earth mixed with the silk.
When digging out the nests of _N. Eleanora_, I have frequently seen
the lower doors pushed forwards so as to close the tube; and it is
my belief that the spider, after having thus barred the passage,
puts her back against the door and resists in this way. I must own,
however, that, though I believe I have seen the spider in this
attitude when I have severed the tube from below, I am not quite
certain about it.
I have twice in the months of April and May, and frequently in
October and November, found young of this species in the nests with
their mother. Usually they were all very small and not larger than
that represented at fig. B 2, Plate IX., p. 98, but occasionally
in October I have found two or three young spiders thrice the size
of their companions still in the nest. On one occasion (in April) I
found twenty-four small spiders clustered beneath and beside their
mother.[71] I secured the whole family by quickly cutting out the
mass of earth containing the lower door on the under side of which
they remained crouched, and brought them home alive. I had up to
this time been in the habit of killing the spiders by placing them
in a stopper bottle full of strong spirit of wine, but on treating
these spiders in this way I saw reason to regret having done so. I
knew that these large spiders, when thrown into spirit of wine, would
continue to struggle for an hour or more, spasmodically spreading
out their legs as if swimming; but I had supposed that this was only
muscular motion, and was not in the least aware that the unfortunate
creatures were probably conscious all the while. In this instance I
first placed the mother spider in the bottle, and then, after the
lapse of about ten minutes, when I supposed that the spider, though
still struggling, was dead to sense, I dropped in the young spiders.
No sooner, however, had I done this than the mother, perceiving them,
gathered all her young to her, and, after placing them beneath her,
with her legs drawn up round them, as a hen screens her chickens with
her wings, never stirred again, and retained this attitude until
death released her, and the limbs, no longer under the control of
this wonderful maternal resolution, slackened and fell abroad.[72]
[Footnote 71: I have found similar families in October and November
in the nests of _N. meridionalis_, only all the young were of nearly
uniform size, and very small. On November 21 I dug out a mother
spider of this species (_meridionalis_) with forty-one little ones!]
[Footnote 72: My own impression is that this act was one of
conscious protection on the part of the mother spider; but Mr.
Pickard-Cambridge doubts this, and would attribute the action to the
tendency which spiders commonly display to clutch at any material
object when dying in this way.]
I need scarcely say that the small spiders were killed by the spirit
in a very few instants, but it is almost certain that the mother was
alive and conscious for half an hour. Now this pain can easily be
spared by placing large spiders for about ten minutes in a closed box
with a piece of cotton wool steeped in chloroform beside them, before
dropping them into the spirit of wine, a system which I have since
that day adopted and found to answer perfectly.
I examined these young spiders carefully, hoping to detect some
males among them, but the males, though they differ markedly from
the females when adult in their smaller size and curiously enlarged
palpi, do not appear to afford any distinctive mark at this early
period. It appeared that these spiders had been but recently hatched,
for some among them were still semi-transparent.
I have never found young spiders in the nests of _Cteniza fodiens_ or
_Nemesia cæmentaria_.
M. de Walckenaer[73] quotes a statement made by M. Rossi to the
effect that _Cteniza fodiens_ carries its young on her back, as
certain species of _Lycosa_ (Tarantula) do. He points out the
interest which would attach to this observation if confirmed, as
showing a similarity in habit between the two groups, which are
otherwise nearly related.
[Footnote 73: Walckenaer (C. A. de), Les Aranéides de France (date?),
p. 5.]
Observations of this kind are difficult to make satisfactorily,
at least in the case of the trap-door spiders with which I am
acquainted, and which appear to be nocturnal in their habits. I have
certainly never seen them out of their nests in the daytime, and but
rarely detected one of them (_Nemesia cæmentaria_) even venturing to
peer out of her door set ajar for the purpose.[74]
[Footnote 74: M. Olivier, however, states (Encyclopédie Méthodique,
tom xviii., p. 228, Art. Araignées Mineuses, Paris, 1811) that he has
twice found nests in the islands off Hyères and on the promontory of
St. Tropez the doors of which were set open in the daytime and the
tube empty, this seeming to imply that the spiders were out hunting
and were diurnal in their habits. He did not see the spiders, but
from his description the nest was of the cork type.... Here is an
interesting point, and one which those naturalists who make Hyères
the field of their observations should endeavour to throw further
light upon.]
The following very singular account is given by M. Erber[75] of the
habits of _Cteniza ariana_, which he watched in the island of Tinos.
I quote from the abstract given in the _Zoological Record_ cited
below:--"At night these spiders come out of their nests, fasten the
open trap-door to neighbouring objects, and spin a net, about six
inches long by scarcely half an inch in height. In the morning the
nets were removed, and Erber believes that the net of each night is
added to the trap-door. He found eggs at the bottom of the tubes,
attached singly to threads, to the number of about sixty. The young
seem to form dwellings very early."
[Footnote 75: In Verhandlungen der k. k. zool. bot. Gesellschaft in
Wien, vol. xviii. pp. 905, 906, quoted in _Zoological Record_, vol.
v. p. 175 (1868); see also Appendix B.]
It would be very interesting to know whether these nocturnal habits
are also found in our spiders on the Riviera.
I have been favoured[76] with a sight of an unpublished manuscript
by Mr. Hansard giving an account of his observations on _Cteniza
fodiens_, made in Corfu. This gentleman states that some of these
spiders which he kept in captivity, used to come out at night, and
might sometimes be surprised roaming about the room at a very early
hour in the morning. He, however, relates that he had received from
a friend an account of a trap-door spider inhabiting the island of
Formosa, in the China seas, which constructed nests similar to those
of _Cteniza fodiens_, but which were habitually to be seen outside
their nests in the daytime, attracting attention by "staring at" any
one who might approach, and then hurrying back to their nests and
closing their doors after them.
[Footnote 76: I am indebted to Mr. Moseley for procuring this MS.,
and to Prof. Rolleston, whose property it is, for permission to make
use of it.]
Lady Parker has also told me of some black trap-door spiders which
were so common about Paramatta, near Sydney, in Australia, that
scarcely any one paid attention to them, and which might habitually
be seen out on the garden paths in the daytime near their holes,
to which they would run in all haste when alarmed. The eye of the
passer-by was attracted by the open doors, which were about the size
of a sixpence, and fall over backwards when the spider makes her
exit, but when closed, on her return, they fit so neatly that it is
extremely difficult to detect them.
It will, perhaps, have been observed that I have throughout spoken of
the female spider only, scarcely any allusion having been made to the
male. The truth is that, though I have carefully searched for them,
I have never been able to secure more than a single male spider.[77]
During the winter, spring, and late autumn (October) the female
appears to live solitary, in the daytime at least, and the male
probably hides in the crevices of old walls and in similar places. I
have diligently turned over piles of stone, greatly to the annoyance
of many little scorpions, but have never secured, or even seen,
another male spider. This is the more to be regretted as the species
of trap-door spider are much better characterized in the male than in
the female sex, the bulb-like enlargement which is found at the end
of the palpi in the former taking on a great variety of forms, each
of which is distinctive.
[Footnote 77: Three days before sending this MS. to print, and long
after the plates had been completed, I captured on Oct. 23rd one male
of _Nemesia Eleanora_. He lay crouched in a crevice in a mossy bank,
and had, perhaps, been driven out of some deeper hiding-place by the
heavy rains.]
M. de Walckenaer[78] says:--"C'est toujours pendant la nuit que
ces aranéides travaillent à leurs habitations et courent après
leur proie. C'est en Août que la Mygale maçonne (_Nemesia_--or
_Mygale_--_cæmentaria_) atteint toute sa grosseur.... En Septembre
elle devient mère et méchante en même temps ... les mouches, les
moucherons, les petits vers lui servent de pâture; elle les prend
dans les filets qu'elle étend et attache sur les inégalités des
terres voisines de sa demeure. Elle vit après la ponte en société
avec son mâle. Dorthès a vu plusieurs fois, dans la même habitation,
le mâle et la femelle avec une trentaine de petits."
[Footnote 78: Les Aranéides de France, p. 4.]
Any one, therefore, who has an opportunity of examining the nests
during the early autumn, might perhaps, discover the happy families
spoken of by M. Dorthès, but which it has never been my good fortune
to see. It is not known positively whether the male spider ever
assists in the construction of the nest, but, as we know that the
female is able to make it without his aid, there seems no reason to
suppose that he does.
I have seen the female _Nemesia meridionalis_ construct a trap-door
in captivity, after having been placed on a flower-pot full of earth
in which I had made a cylindrical hole.[79] She quickly disappeared
into this hole, and, during the night following the day of her
capture, she made a thin web over the aperture, into which she
wove any materials which came to hand. The trap-door at this stage
resembled a rudely constructed, horizontal, geometrical web, attached
by two or three threads to the earth at the mouth of the hole, while
in this web were caught the bits of earth, roots, moss, leaves &c.
which the spider had thrown into it from above. After the second
night the door appeared nearly of the normal texture and thickness,
but in no case would it open completely, and it seemed that the
spider was too much disgusted with her quarters to think it worth
while to make a perfect door. I believe that when a door is finished
the few threads which served as supports and connected it with the
earth on either side of the hinge are severed, and this is borne out
by the following instance. While I was at work one evening drawing
the spider's nest concealed in the plant of ceterach fern (Plate
XI., fig. A, p. 105) which I had dug out for the purpose, I detected
something moving at the mouth of a tiny hole [just large enough to
admit a crowquill pen] in the mass of earth on the opposite side of
the fern, to that in which the large trap-door lay.
[Footnote 79: An account of further experiments with captive spiders
will be found in Appendix G.]
The lamp-light fell full upon it, and I soon saw that the moving
object was a very small spider, not bigger than that drawn at B 2
in Plate IX., which was at work in the mouth of its tube. Whether
I had, in removing this mass of earth, destroyed the door I cannot
say, but it is certain that the opening of the tube was completely
uncovered, and it soon became apparent that the little spider was
intent upon remedying this deficiency. After a few threads had been
spun from side to side of the tube I watched the spider make one or
two hasty sorties, apparently spinning all the while, and finally I
saw her gather up an armful, as it were, of earth and lay this on the
web. After this the occupant of the tube was concealed, but I could
see from the movement of the particles of earth that they were being
consolidated, and that the weaving of the under surface of the door
was being completed. Next morning I was able to lift up the door,
which had the form of a small cup of silk, in which the earth lay. It
was then soft and pliant, but in ten days time it had hardened and
become a very fair specimen of a minute cork door (see figs. A 1, A
2, of Plate XI.).
On one occasion a captive _Nemesia meridionalis_ employed some pieces
of scarlet braid which I had purposely strewed, along with bits of
moss and fragments of leaves, in a circle round the opening of, and
about two inches away from, the hole.
It is probable that these spiders have in times past learned by
experience that they cannot do better than take such materials as
come to hand, as these will ordinarily serve for the concealment of
their door.
However, these trap-door spiders do seem to exercise some
discrimination in the choice of materials; for I have observed
several instances in which, when the door of a cork nest has been
removed, if the door was originally covered with moss, moss will
again be used in its reconstruction, even though the mouth of the
tube be then surrounded by bare earth.
Thus, for example, in one case where I had cut out a little clod of
mossy earth, about two inches thick and three square on the surface,
containing the top of the tube and the moss-covered cork door of _N.
cæmentaria_, I found, on revisiting the place six days later, that a
new door had been made, and that the spider had mounted up to fetch
moss from the undisturbed bank above, planting it in the earth which
formed the crown of the door.[80] Here the moss actually called the
eye to the trap, which lay in the little plain of brown earth made by
my digging.
[Footnote 80: Mrs. Boyle first called my attention to this curious
fact, of which I have since seen many examples. I have purposely
removed several cork doors from mossy banks in order to observe this
point.]
I have seen the same thing happen when the door of _N. Eleanora_
has been removed and replaced, moss being again used in the work
of reconstruction. Trap-door spiders in warm weather very quickly
replace their trap-doors; and if you pass by a wall where several
nests have been robbed of their doors only a week before, they will
usually be found quite perfect again.
It has been stated[81] that, if the door of a cork nest be fastened
down with a pin, a second door will be found next day by the side of
the former one. No doubt spiders not unfrequently find their doors
blocked up by a fall of earth, and are thus obliged either to make a
new opening or to prolong the old tube.
[Footnote 81: M. Dorthès on the Structure and Œconomy of some Curious
Species of Aranea, in Trans. Linn. Soc. (London), II. 88-90.]
I once fastened open the surface doors of three of the double-door
nests by passing a thread through the silk of the door and tying it
back to some twigs above. The doors were thus turned backwards, and
the aperture of the tubes, which lay in a vertical terrace wall,
exposed to view.
Next day, after a night of very heavy rain, I found the doors as I
had left them, but in one nest the lip of the tube had been dragged
inwards so as partially to close the tube; in the second nothing
appeared to have been done, but in the third nest a new covering had
been very cleverly extemporized out of three fallen olive-leaves,
which were loosely spun together and attached by one or two threads
to the margin of the tube. This formed an admirable concealment,
but did not move freely as a door, the web being too imperfect. Two
days later, however, it was completed and had become a perfect door,
moving on a hinge just within and below that of the former door,
which still remained as I had fastened it. The other nests remained
in the same condition as before, only that a little moss had been
dragged into the mouth of the tube of the nest, which had been
partially closed with its own lip.
The extreme reluctance which these spiders show to abandon their
dwellings is curiously exemplified by what follows.
Certain nests which were furnished with two doors of the cork type
were observed by Mr. S. S. Saunders[82] in the Ionian Islands.
The door at the surface of these nests was normal in position and
structure, but the lower one was placed at the very bottom of the
nest and inverted, so that, though apparently intended to open
downwards, it was permanently closed by the surrounding earth. The
presence of a carefully constructed door in a situation which forbade
the possibility of its ever being opened seemed, indeed, something
difficult to account for. However, it occurred to Mr. Saunders that,
as these nests were found in the cultivated ground round the roots
of olive-trees, they may occasionally have got turned topsy-turvy
when the soil was broken up. The spider then, finding her door buried
below in the ground and the bottom of the tube at the surface, would
have either to seek new quarters or to adapt the nest to its altered
position, and make an opening and door at the exposed end. In order
to try whether one of these spiders would do this Mr. Saunders placed
a nest, with its occupant inside, upside down in a flower-pot.
After the lapse of ten days a new door was made, exactly as he had
conjectured it would be, and the nest presented two doors like those
which he had found at first.
[Footnote 82: Description of a species of Mygale from Ionia in Trans.
of Ent. Soc. (London, 1839), III. p. 160.]
There is a specimen of one of these inverted nests, with its two
doors, in the British Museum, and this might easily be supposed, at
first sight, to be an example of a new kind of double-door nest. On
close inspection, however, it will be seen that one of the two doors
is discoloured and partly decayed, this being, no doubt, the one
which had been buried beneath in the earth and so rendered useless.
Questions have often been asked as to the manner in which trap-door
nests are commenced in the first instance, and whether the weaving of
the silk lining is begun at the top or the bottom of the tube.
The structure of the cork door also, which often appears so perfectly
turned as to resemble the work of a potter's lathe, is another
difficulty.
These questions have, as it seems to me, been needlessly complicated
by taking it for granted that the perfect nest of the mature spider
is made all at one time, that the tube, perhaps of a foot in length,
is excavated, lined, and furnished with a door within some short
period of time, such as ten days or a fortnight, perhaps.
On the contrary, I believe that the nests are, as a rule, the result
of many successive enlargements, and that the nest of the infant, the
tube of which is no bigger than a crowquill, is not abandoned, but
becomes that of the full-grown spider. This must require time, but
how long, whether months or years, we have yet to learn.
Very little is known at present as to the longevity of spiders, but
Mr. Blackwall[83] says that some live only one year, while others,
such as _Tegenaria civilis_ and _Segestria senoculata_, have been
known to live four.
[Footnote 83: Spiders of Great Britain and Ireland, p. 8.]
Whether the trap-door spiders are very long lived or not I cannot
positively say, but, from the appearance of the growth of moss and
lichen on the doors of some nests which I have observed, I am
inclined to think that they must have been inhabited for more than a
twelvemonth.
Evidence of the enlargement of the door is not very rare to meet
with, though, as a rule, the new piece is woven on to the old with
such neatness as more or less to obscure this. In fig. B, Plate
X., p. 100, the old and smaller surface-door of a nest of _Nemesia
meridionalis_ is seen partially attached to the larger new door,
which has been constructed below it; while in fig. C of the same
plate, three doors, or rather three enlargements of one door, may
be traced. It is this, I believe, that gives rise to the tiled
appearance which these trap-doors sometimes present, and which has
caused them to be compared to oyster-shells. Something similar may
also be occasionally seen in doors of the cork type, as, for example,
in that figured at A and A 1 in Plate VIII., p. 94, where the old
and smaller door is seen partially raised above the surface of the
new one. This I imagine to be merely an example of rather clumsy
workmanship, as, if I am right, a full-sized cork door usually
incloses within itself several lesser doors, which formerly fitted
the tube and have had to be enlarged.
This is borne out by the fact that such a door will, on examination,
be found to consist of several layers of silk, with more or less
earth between each, these layers decreasing in size from without
inwards, and together forming a sort of saucer in which the small
central mass of earth lies. Thus by moistening a series of the cork
doors of _Nemesia cæmentaria_, I have been able to detach, in one of
medium size, from six to fourteen circular patches of silk, of which
the outermost, or that which forms the lower surface of the door,
is the largest, and the innermost the smallest, the others being
intermediate in size as in position. Perhaps if I had had larger
doors at my disposal for examination I might have found more layers,
as other authors[84] speak of a much greater number of layers in the
cork doors of _Cteniza fodiens_. Be this as it may, I am confirmed in
my opinion that the layers of silk mark the successive enlargements
of the nest by the additional fact that in very small doors the
layers of silk are few or single, and that a proportion is observable
as a rule between the size of the door and the number of layers of
which it is composed.[85]
[Footnote 84: M. de Walckenaer seems to have found more than thirty
alternate layers of silk and earth in one of the doors of _Cteniza
fodiens_, as we may gather from the following:--"Quoique cette
porte n'ait guère que trois lignes d'epaisseur, elle est formée par
la superposition de plus de trente couches de terre séparées les
unes des autres par autant de couches de toile. Toutes ces assises
successives s'emboitent les unes dans les autres comme les poids de
cuivre à l'usage de nos petites balances. Les couches de toile se
terminent au pourtour de la porte." Walckenaer, Histoire des Insectes
Aptères (Suites à Buffon), vol. i. p. 238 (Paris, 1837).
I have not found the regular layers of earth and silk of which M.
de Walckenaer speaks, the silk layers being usually in contact
at their centres and only separated by a little ring of earth
interposed between their edges, this earth being thickest towards the
circumference of the layers of silk.]
[Footnote 85: This may be seen by the comparison of the composition
of doors of different sizes, given in Appendix H.]
Another proof that enlargement takes place, may at times be found in
the nests of _N. Eleanora_, where one, or even two useless doors may
be detected behind the lower door.
Now when there are three lower doors in this way the one which is in
use is the largest, and the door lying nearest to this one the next
in size, while the hindmost is the smallest of all. But though those
abandoned doors are now too small to fit the existing tube, they did
so, no doubt, in their day, for they are exact copies in miniature of
the ordinary horse-shoe shaped lower doors. The lower door actually
in use may sometimes be found to have two separable cases of thick
silk enclosing the central mass of earth, and this also, very
probably, represents enlargement. In the nests of _N. meridionalis_ I
have never found any of these abandoned doors behind the one in use,
nor should I expect to find any, for if they were present they would
permanently obstruct the entrance from the main tube to the branch.
It is clear that it is better economy on the part of the spider to
enlarge its nest rather than build a new one each time. If we compare
the infant spider and its nest (fig. B, Plate IX., p. 98) with the
full-grown creature and its nest (fig. A, Plate IX.), it becomes
evident that the growing spider must either construct many nests of
intermediate size, or frequently enlarge the original domicile. And
we do in fact find nests of all sizes between the two extremes.
I cannot help thinking that these very small nests, built as they are
by minute spiders probably not very long hatched from the egg, must
rank among the most marvellous structures of the kind with which we
are acquainted. That so young and weak a creature should be able to
excavate a tube in the earth many times its own length, and know how
to make a perfect miniature of the nest of its parents, seems to be a
fact which has scarcely a parallel in nature.
When we remember how difficult a thing it is for even a trained
draughtsman to reduce by eye a complicated drawing or model to a
greatly diminished scale, we must own that the performance of this
feat by a baby spider is so surprising as almost to exceed belief.
And yet even the most complicated form of nest--namely, that of the
branched double-door type--is perfectly reproduced in miniature by
these tiny architects, with the upper door, lower door, main tube,
and branch (fig. B, Plate IX., p. 98).
In order to test whether the doors are enlarged or not I measured the
surface doors of seven double-door nests and one minute cork door on
April 30th, making a careful plan of the terrace wall in which they
lay, in order to make sure of finding them again on my return to
Mentone in October.
The following table will show that all were enlarged, the average
rate of increase being 1-7/10 lines in the five and a half months
which had elapsed:--
_Measured April 30, 1872._ | _Measured Oct. 18, 1872._
|
No. I. 9 lines across | No. I. 10-1/2 lines across
II. 4 " | II. 5-1/2 "
III. 4-1/2 " | III. 5-1/2 "
IV. 4 " | IV. 4-1/2 "
V. 2 " | V. 3 "
VI. 2-1/2 " | VI. missing
VII. 1 " (the cork) | VII. 2 lines across
VIII. 5 " | VIII. 7-1/2 "
We can scarcely venture from such limited premises to draw any
precise conclusions, but if we suppose that during the entire course
of the year the nests increase on an average by about four lines in
diameter, and assume that the rate of growth continue the same, the
nest of the infant spider, whose surface door measures scarcely a
line across, would still require four years to attain the dimensions
of some of the largest double-door nests, whose surface doors measure
sixteen lines across.
It seems to be the rule with spiders generally that the offspring
should leave the nest and construct dwellings for themselves when
very young.
Mr. Blackwall,[86] speaking of British spiders, says:--"Complicated
as the processes are by which these symmetrical nets are produced,
nevertheless young spiders, acting under the influence of instinctive
impulse, display, even in their first attempts to fabricate them, as
consummate skill as the most experienced individuals."
[Footnote 86: Loc. cit., p. 11.]
Again, Mr. F. Pollock[87] relates of the young of _Epeira aurelia_,
which he observed in Madeira, that when seven weeks old they made a
web the size of a penny, and that these nets have the same beautiful
symmetry as those of the full-grown spider. Those of the latter are
vertical, circular, made of about 250 feet of thread, having about
35 radial lines and 38 concentric circles, the outermost of which
is some 20 inches in diameter. After the lapse of a day or two the
web loses its adhesive property and a new one is made. In about six
months the female _Epeira_ has completed her ten changes of skin, one
of which takes place in the cocoon, and "at the end of eight months
the spider is 2700 times as heavy as at its birth." This _Epeira_
lives, we are told, for about eighteen months.
[Footnote 87: The History and Habits of _Epeira aurelia_, in Annals
and Mag of Nat. Hist. for June, 1865.]
One can scarcely contemplate the work of these architects and
weavers, and especially of the trap-door makers, without being
carried away into the whirlpool of discussion which has so long raged
round the word _instinct_.
Do the young spiders build their first nest by instinct--that is to
say, independently of all teaching or personal experience--or do they
copy the nests in which they were hatched?
What is wanting, however, is not discussion, of which we have had
enough, but demonstration, and demonstration is hard to come by,
depending as it must upon careful and repeated experiment.
If it were practicable, and I have no reason to know that it is not,
to rear spiders from the egg away from the nest, and then to cause
them to build in places where they should be perfectly at home and
yet cut off from all communication with their kind, we might hope to
learn whether they can construct the characteristic nests of their
species without ever having seen one.
Mr. Wallace[88] shows that there is some reason to doubt whether
birds, which are so frequently said to build by instinct, would,
under parallel circumstances, construct the nest proper to their
kind; and he states that birds brought up from the egg in cages do
not do so, nor do they even sing their parents' song without being
taught.
[Footnote 88: Chapters on Instinct and on the Philosophy of Birds'
Nests, in his Contributions to the Theory of Natural Selection.]
Of course we can scarcely compare birds and spiders together, but we
should hesitate, in view of Mr. Wallace's expressed opinion as to the
nest-building habits of the former, to assume that the latter are
independent of teaching and personal experience. It may very possibly
be so, but it has never been proved.
I have endeavoured to gather together all the published records
of the nests of spiders belonging to the sub-order _Territelariæ_,
with a view, if possible, to trace out the geographical range of the
several types of structure. I have, however, met with but a small
amount of success, and even among the limited number of tolerably
complete accounts of nests which I have been able to discover,
several made no mention of the spider to which the nest belongs.
Prof. Ausserer[89] has enumerated 215 species of _Territelariæ_ as
having been found in the world at large, but of this large number
ten only, as far as I have been able to learn, have been described
in connexion with their nests, and eight of these belong to the
Mediterranean region.[90] To these we may now add two more, namely,
_Nemesia meridionalis_, with its branched double-door nest, and _N.
Eleanora_ the builder of the unbranched double-door nest, thus making
twelve in all.
[Footnote 89: In his monograph of _Territelariæ_ quoted above.]
[Footnote 90: I use this term in its widest sense, making it even
include Morocco. A list of the species known to inhabit this region
will be found in Appendix C.]
Three of the twelve, however, _Atypus piceus_, _A. Blackwallii_, and
_Nemesia cellicola_,[91] do not appear to build true trap-doors, but
only a simple silk tube without any covering at the mouth.
[Footnote 91: See Appendix A, p. 141.]
The following tabular view will show to which of the four types of
trap-door nest those of the remaining nine spiders belong, and their
geographical distribution:--
TRAP-DOOR SPIDERS WHICH BUILD
Nests of the cork type.
_Idiops syriacus_, Beirût.
_Cteniza fodiens (Ct. Sauvagei)_, Corsica, Pisa, Mentone.
_Ct. ædificatoria_, Tangiers.
_Ct. (Cyrtocarenum) ionicum_, Ionian Islands.
_Ct. (Cyrtocarenum) Ariana_, Naxos, Tinos.
_Nemesia cæmentaria_, South of France, Spain, Sardinia, Corsica,
Sicily, Algiers, and the var. _germanica_ from Wippach, near
Görz.
[Nests, apparently of the true cork type, have also been found in
Australia, New Granada, India, and the island of Formosa, but their
occupants are unknown.]
Nests of the single-door wafer type.
_Cteniza nidulans_, West Indies (and South America?)
Nests of the double-door branched type.
_Nemesia meridionalis_, Mentone, Cannes, and Sestri, near Genoa.
Nests of the double-door unbranched type.
_Nemesia Eleanora_, Mentone, and Cannes.
As far, therefore, as I know at present, the cork type of nest is the
only one which is widely spread, and which is constructed by spiders
of more than one species. For, while the single-door wafer, and the
branched and unbranched double-door nests are each the work of one
particular spider, we see that nests of the cork type are made by
spiders of six distinct species, belonging to at least three genera.
It is almost certain that a much larger number of spiders of
different kinds, though all probably members of the sub-order
_Territelariæ_, construct nests of the cork type, for descriptions
and specimens of trap-doors of this kind are brought from the most
distant parts of the globe. It is true that these specimens and
descriptions usually only show us the surface-door, but as far as our
present knowledge goes, we are led to suppose that a door of the
cork type is always associated with a simple tube, in which there is
no trace of a second door or valve, so that, judging of the unknown
by the known, we conclude that nests which possess the characteristic
peculiarity of a true cork door are true cork nests in other respects
also. Further research may possibly show that there are exceptions to
this generalization, but I do not at present know of any.
I have seen Australian specimens of large trap-doors, of the cork
type, measuring from one to two inches across. In some of these the
doors were scarcely more than semicircular but very thick, and having
their edges bevelled so as to correspond with the sloping margin of
the tube;[92] in others, found at Paramatta, and described to me by
Lady Parker as being tenanted by a black spider, the doors were said
to be circular and much smaller, scarcely larger than a sixpence, and
of the cork type.
[Footnote 92: Specimens of Australian nests may be seen in the cases
at the British Museum.]
The upper portion of a nest from New Granada has been figured and
described by M. Victor Audouin,[93] which closely resembles that
drawn at Fig. A in Plate VII., p. 88, but the door is about a third
larger.
[Footnote 93: Note sur la demeure d'une araignée maçonne de
l'Amérique du Sud. Annales des Sciences Naturelles (Zoologie), tom.
vii. tab. 3, p. 227-231.]
I have also been assured that nests of the cork type are found in
many parts of India, and we have seen above that they are reported to
be common in the island of Formosa.
Putting all this together, it will be seen that nests of this type
are found all round the globe; in Formosa, India, Syria, the Grecian
Archipelago, Italy, and the adjacent islands, Trieste, South France,
Spain, Morocco, New Granada, and Australia; while the single-door
wafer nest is only known at present in the West India islands;[94]
the branched double-door nest at Mentone, Cannes, and Pegli near
Genoa, and [doubtfully] near Naples and in Ischia; and the unbranched
double-door type at Mentone and Cannes alone. It is quite probable
that these three latter forms of nest will some day be found to
have a much wider range than that assigned to them here, but I can
scarcely think it likely that they will ever be shown to claim the
world-wide distribution of the cork type. Supposing that these nests
are eventually discovered in many widely distant localities, a very
interesting question will arise as to the specific characters of
the spiders which inhabit and construct them. Shall we then find,
for example, that nests of the unbranched double-door type are not
tenanted and fabricated by _Nemesia Eleanora_ alone, as we have
hitherto found to be the case, but by many other distinct species
also, each in its peculiar district?
[Footnote 94: There is a nest exhibited in the Museum collection at
the Jardin des Plantes at Paris, marked "Amérique du Sud," which is
perhaps of this type.]
That is to say, will the type of nest remain the same while the
occupants vary, as in the cork nests?
If, on the other hand, we learn that these three types, the
single-door wafer, the branched and unbranched double-door nests, are
very local, we shall be led to inquire into the probable causes of
this limitation.
But we must study much more closely the habits of these trap-door
spiders, and the difficulties and dangers to which they are exposed,
if we wish to appreciate fully the true meaning and intention of
the structure of their nests, and to find the clue to the difficult
question why one type should be more frequently adopted than another.
Above all, we must discover what are their enemies, and how and when
they are most exposed to them. M. de Walckenaer gives an entertaining
account[95] of the enemies to which spiders generally are exposed,
and of this the following list is an abstract.
[Footnote 95: Histoire des Insectes Aptères (Suites à Buffon), vol.
i. p. 172-7.]
Many kinds of monkeys, squirrels, and several sorts of birds, as
well as lizards, tortoises, frogs, and toads prey upon spiders. A
species of black sheep, found in the steppes of Asiatic Russia,
unearths the tarantulas (Lycosa), and eats them. ("Une espèce de
brebis noire, dans les steppes de la Russie asiatique, déterre les
tarentules et les mange"). In the East India Archipelago there
is an entire genus of birds of the passerine order, which have
been named "Arachnoptères" because the different species of which
it is composed live exclusively on spiders. Besides these, the
centipede (_Scolopendra_), and the following Hymenopterous insects,
_Philanthes_, _Sphex_, _Pompilus_, _Pimpla Ovivora_, and _P.
Arachnitor_ [which last lay their eggs in the eggs of spiders], carry
on perpetual hostilities against them.
I have seen it stated that ants are among the worst enemies of
spiders, driving their galleries through the silk tubes of the latter
and devouring their eggs. Of this I have never seen any trace, and,
on the contrary, have on four occasions found the remains of ants'
bodies at the bottom of the trap-door spiders' nests.
I have but seldom detected any refuse in these nests, and this
accords with what M. Erber tells us[96] of the care with which
_Cteniza Ariana_, which he watched by moonlight in the island of
Tinos, carried away the empty bodies of the beetles, the juices of
which had been sucked out, to a distance of some feet from its hole.
In October, 1872, however, I found a black layer of débris at the
bottom of five nests of _Nemesia Eleanora_, and this was composed
principally of the remains of insects, and among others of some
rather large beetles.
[Footnote 96: A translation of these very interesting observations
will be found below in Appendix B.]
As far as I am aware, M. Erber is the only naturalist who has ever
placed any detailed observations on record as to the nocturnal habits
of a trap-door spider in its native haunts; and we may learn from
him how we should watch these creatures, if we wish to discover the
manner in which they take their prey, and of what their prey consists.
He relates how he witnessed the capture, in the long low snare
which _Cteniza Ariana_ spreads close to the ground, of two strong,
night-flying beetles (_Pimelia_ and _Cephalostenus_), and how these
were at once devoured, and their horny coats thrown away.
More observations of this kind are greatly wanted, as it is most
important that we should know what are the principal sources of food
upon which these spiders depend for their existence.
If we could answer the questions, what do they eat? and what do they
fear? we should have advanced a long way towards resolving the larger
problem as to the causes which limit particular species to certain
districts.
I greatly envy those who are able to travel, and who have it in their
power to investigate the habits of these creatures at several widely
separated points; for there seems every probability that other new
types of nest remain to be detected in warm climates, some of which
may perhaps exceed those we have been here studying in beauty of
workmanship and adaptation; it is at least certain that an abundant
harvest of interesting facts in the life history of trap-door spiders
remains yet to be gathered in.
Indeed it appears to me that we are only on the threshold of
discoveries of this kind, and that the materials brought together in
the preceding pages may be considered as but a small sample of what
may be collected on the outermost edge of this great domain.
I shall be satisfied if I have been able in the present little work,
to hold the door sufficiently ajar to permit those who love nature
and her ways to catch a glimpse of the wonders and beauties of the
untrodden land that lies beyond.
APPENDIX.
A.
_Nemesia (Mygale) meridionalis_, Costa.[97]
[Footnote 97: Costa, Fauna del Regno di Napoli, Aracnidi (1861), p.
14, tab. i. figs. 1-4. [Translation.]]
"M. fusco rufoque-flavicante, maculis obscurioribus, thorace
radiatim, abdomine seriatim dispositis, subtus thorace rufescente,
abdomine flavidulo, mandibulis spinarum serie unica, tarsis omnibus
spinulosis."
"The cephalothorax oval, elongated and truncate in front, while the
head is smooth and bare, with a group of eight eyes, a little keeled
in the middle; of a fulvous-brown colour, with ten rather dusky
spots arranged in rays, and corresponding to the direction of the
eight legs (anche) and the two maxillæ. The mandibles are large,
horizontal at first, then curved downwards, making a quarter of a
circle, furnished with numerous hairs, especially on the inner side,
and at the anterior extremity above there are mobile and rather long
spines; below they are channelled, with six little teeth or spines
on the edge (rilievo) of the inner face, clothed with many bristling
hairs, with which the outside is also covered, but without any teeth;
on the inner face they are flattened, so that they fit perfectly
close. The fang is strong, curved, acute, and black. The maxillæ
are clothed with brown hairs almost as the legs are, and at their
extremity, on the outer side, stand the long palpi, rather hairy
(pelacciuti), terminated by a very short and simple little claw.
The sternal lip is very small and round. The abdomen oval, longer
or shorter according to age, dusky ash in colour, spotted with
brown, and covered with short and depressed (rasicci) hairs. The
brown spots are disposed in slanting lines, placed obliquely to the
median line, which is also brown; below it is somewhat lighter, and
becomes slightly yellow, increasingly so in the female as pregnancy
advances. The pulmonal sacs are always pale yellow, and involved in
the fold (tramezzati dalla ripiegatura). Between these, and within
the fold itself, the female sexual organ opens, consisting of a
transverse opening invisible to the naked eye, but clearly seen on
using a lens and removing the fold under which it is concealed, by
means of the point of a scalpel or of a pin. The posterior extremity
of the anus presents four spinnerets, of which the two upper are much
the longer, and composed of four easily seen joints, the lower very
short. The feet are moderate, and the longest are of the length of
the entire body when this is fully developed (quando è perfettamente
sviluppato); of these the fourth pair are about a third longer
than the first, the third of about the same length as the second,
which is the shortest of all. The tarsi of these are armed with two
small curved claws, and the third and fourth joint with many long,
delicate, straight, and mobile spines, which in the first pair become
fewer as they approach the last joint. The eyes are arranged in three
lines, as they are represented in C, Plate I., Fig. 3, and of these
the two last of the posterior line are white and glistening, the
others brown.
"Our _Mygale_ lives in tubular cavities, or burrows, which she
excavates for herself in loose and friable soil, in walls made of
volcanic earth, in shady places, and for the most part turned to the
north or to the west, seldom to the south--hence cool and rather
damp. The burrows do not exceed the length of a palm, eight lines at
their widest part. For about the length of an inch the tube is funnel
shaped, thence it continues of a nearly uniform magnitude. Its first
direction is almost horizontal, then it rises continually, turning
to the right or left, and sometimes makes zigzags. As the tubes are
excavated in friable soil, she takes care to tapestry them inside
with the same glutinous material of which the other races make their
web, by means of which the burrows are made smooth on the inside, and
to strengthen them in such a manner that even when the outer earthy
part has become cracked, or been torn away by the action of the rain,
they remain firm and fit to conceal their inhabitant. I have often
found the tubes of web thus left exposed, as they are represented
in Plate I., Fig. 4, situated in the cement of a wall, and among
_Lycopodium denticulatum_, _Adiantum Capillus-Veneris_, _Marchantia
polymorpha_, and other small plants. And it seems that the animal,
perceiving the nature of the soil, takes care to reinforce the
silken case, so much the more as she finds the earth less firm, and
_vice versâ_. So that in burrows excavated in solid ground, with
the exception of a little space close to the aperture, the nest is
merely smoothed and daubed; while sometimes the spider constructs a
tube so strong that it supports itself even when deprived of all the
earth, the animal having had the foresight to attach it along the
course of the clefts of the rock, or to the cement of the pieces of
tufa in the wall, as represented in Plate I. They have often also a
double aperture, and the upper portions of the burrows converging,
meet and anastomose at about two inches distance. The aperture is
closed by a little door or valve (_a_), which, having its hinge in
the upper part and a little on one side, falls by its own weight, and
fits itself exactly to the opening. The outer surface of the wicket
is covered with earth, cemented by the glue of the spider, so that
it is rendered imperceptible to common eyes, and the industrious
little creature takes care to leave around the aperture a kind of
rim, to which the door fitting closely, leaves no passage for any
animal, nor does it show its edges. At the bottom of its tube the
creature keeps her numerous offspring, and always stands herself as
sentinel at the door, holding the wicket raised by means of the four
anterior feet, and the palpi, curved extremities of which she inserts
between the rim of the tube and of the door, as represented in _a'
f_. Sometimes, however, they do not appear, but she leaves only the
chink for observation, as one sees in _a_ of the same figure. Fig.
2, at _c_, represents the aperture of an abandoned burrow, and at
_d_ the raised door of another burrow, with its almost funnel-shaped
aperture. That which Sauvage, Olivier, and Latreille relate of her
is not true--namely, that she remains at the bottom of the burrow,
and runs to the door only when she sees it threatened, in order to
keep the door firmly closed. On the contrary, always standing at the
door as sentinel, she leaves it as soon as she thinks it in danger,
so that it can be raised without the least effort: but if you hold
it a little raised without making any sign of movement, she turns
on her back, and comes out to draw it down with her feet, making
all the efforts she can to conquer the obstacle. But if you take
it away entirely, she turns down the edges to close the aperture
as best she can, and that she does hurriedly, without waiting for
night. The light seems to offend her so much that, if exposed to the
full day, she remains so stupefied as to appear dead, nor does she
move even if shaken; on the contrary, she constantly stops still and
holds herself with her feet pressed against her body. At last, if
very much disturbed, she runs quickly for some distance, till she
finds a place in which to hide her head, and from thence she does
not stir. I have observed that the burrows are always short when
the aperture is small, and increase in length as they augment in
diameter, which makes me conclude that it is not true that they begin
their excavations from the base of the mother's tube, where I have
never found any communication with others. This spider is found in
the neighbourhood of Naples (ne' contorni della Capitale), on the
Camaldoli, in the island of Ischia, where it lives near the sources
of mineral waters, in Gaeta at the foot of the olive trees, among the
stones in the ground, &c. &c.
"Observation. The difference which distinguishes our _Mygale_ from
the _Sauvagesii_ consists, first, in the toothing of the mandibles,
which is observable on one side only of the channel, and not on both;
secondly, in the tarsi all equally armed with spines, and not only
the four anterior ones; thirdly, in the colour of the thorax and
the abdomen, which is not uniform as is usual in the _Sauvagesii_.
Nevertheless, such differences might be in part climatic, which would
cause our _Mygale_ to be considered as a mere variety of the same
species, and the others might be the result of the different method
of examining the parts, and of the goodness of the instruments."
At p. 19, in the _Fauna del Regno di Napoli_, M. Costa gives the
following account of the nest of _Nemesia cellicola_, which he
discovered above San Martino in September, 1833:--
"Vive entro la polvere arida, nelle cavità oscure delle muraglie, e
propriamente nelle così dette _Saettiere_, ove, col glutine suo, si
costruisce un tubo delicato e mobile, che ha cura di affidare nel suo
origine a qualche corpo stabile nel fondo del muro, e che in terra
nella polvere, aprendosi l'altro estremo sul piano inclinato dalla
polvere stessa costituto."
This, with the exception of the words "e che in terra nella polvere,"
which are unintelligible to me as they stand, and appear to want a
verb, may be translated as follows:--
"She lives in the dry dust, in the obscure crevices of walls, and
especially in those which are called _Saettiere_ (loop-holed walls?),
where she constructs a delicate and flexible tube with her viscid
secretion, and which she takes care to fasten at its commencement to
some solid body at the bottom of the wall, ... the other extremity
opening on the inclined plane formed by the dust itself."
We may remark that there is here no mention of any door or
concealment at the mouth of the tube, and in this and some other
respects the nest of _Nemesia cellicola_ would appear to resemble the
nest of _Atypus piceus_ from the neighbourhood of Paris. See above in
the text, p. 78.
B.
_On the Habits of Cteniza Ariana._
The following is a free translation of an account read by M. Erber
before the Botanico Zoological Association of Vienna,[98] of the
very curious observations which he made on _Cteniza Ariana_ when
travelling in the Grecian Archipelago.
[Footnote 98: Verhand. der k. k. zoologisch-botanischer Verein in
Wien, vol. xviii. (1868), p. 905.]
"On my return voyage [from Rhodes], I stayed for a fortnight in
the island of Tinos, and, among other things, I captured several
specimens of the so-called trap-door spider (Deckelspinne) _Cteniza
Ariana_, Walck., and with much trouble procured an entire tube and
trap-door of this creature.... I am thus enabled to exhibit to this
honourable assembly the complete nest of this creature, and the
spider herself, with her eggs, preserved in alcohol, and can moreover
add some few words as to her habits.
"It needs some practice, as the specimen before you shows, to enable
one to discover the nest, as the door is always closed by day. I dug
out several of these tubes, but failed to find either the remains of
food or excrement. So there was nothing for it but to devote a couple
of nights to watch these creatures. With this view I selected a place
where many spiders had excavated their tunnels, and availed myself of
a moonlight night for my observations.
"Shortly after nine o'clock the doors opened and the spiders came
out, fastened back the trap-doors by means of threads to neighbouring
blades of grass or little stones, then spun a snare about six inches
long by half an inch high, and afterwards returned quietly to their
holes.
"I had so chosen my position that I could see three of these spiders
at the same time. I now captured a specimen and put it into spirits,
and in a short time saw entangled in the net of one of the remaining
spiders a _Pimelia_, and of the other a _Cephalostenus_, both rather
hard-lived, night-flying beetles, which were seized by the spiders,
and the latter, after sucking out the juices, carried the empty
bodies to a distance of several feet from their holes. All these
events happened in about three hours, after which time I allowed the
two spiders to remain undisturbed, and returned to the house.
"Early next morning I revisited the spot, and then perceived that
these two spiders had entirely removed the net which they made the
preceding night, but the entrance to the nest of the spider which
I had captured still remained open, and I could clearly trace the
shape of its snare, on which the heavy morning's dew lay. The upper
threads were isolated, but the snare became thicker as it approached
the ground. I found that these snares had, strange to relate, been
gathered up by the two other spiders, fastened on to the door, and
smoothly spun over, and, on making a vertical section of the doors,
which were nearly a quarter of an inch thick, I discovered that they
were composed of several layers.
"In the nests of several females I found eggs at the bottom of the
tube, not placed in cocoons, but attached by separate threads. The
young spiders when hatched are turned out from the asylum of their
mother's nest; and I found these creatures when scarcely two lines
long already established in nests three inches deep, and furnished
with perfect trap-doors, of which facts the specimens I now lay
before you are the evidence."
C.
Species of Territelariæ, enumerated by Professor Ausserer,[99]
belonging to Europe and the Mediterranean region, with synonyms, and
two species which I have added in brackets:--
[Footnote 99: Beiträge zur Kenntniss der Arachniden-Familie der
Territelariæ, in k. k. zool.-bot. Gesellschaft in Wien (1871), vol.
xxi. pp. 117-224.]
_Atypus piceus_, Sulzer. (_A. Sulzeri_, Latr.) Holland, France,
Switzerland, Germany, Northern Italy.
_A. Blackwallii_, Auss. England.
_A. Anachoreta_, L. Koch. Fiume.
_Idiops Syriacus_, Cambr. Beirût.
_Æpycephalus brevidens_, Doleschall. Sicily.
_Cteniza Sauvagei_, Rossi. (_Ct. fodiens_), Corsica, Pisa, Mentone,
Ionian Islands.
_Ct. orientalis_, Auss. Brussa.
_Ct. ædificatoria_, Westw. (_Actinopus ædificatorius_, Westw.)
Tangiers.
_Ct. algeriana_, Luc. Algiers.
_Cyrtocarenum Arianum_, Walck. (_Mygale (Cteniza) Ariana_, Walck.).
Naxos, Tinos.
_C. tigrinum_, L. Koch. Syra.
_C. grajum_, C. Koch. Nauplia in the Morea.
_C. ionicum_, Saunders. Ionia.
_C. lapidarium_, Luc. Crete.
_Cyrtauchenius Walckenaerii_, Luc. Algiers.
_C. Doleschallii_, Auss. Sicily.
_C. similis_, L. Koch. Saragossa.
_C. obscurus_, Auss. Sicily.
_Nemesia cæmentaria_, Latr. S. France, Spain, Sardinia, Corsica,
Sicily, Algiers.
_N. cæmentaria_, var. _germanica_, Auss. Wippach, near Görz in
Trieste.
[_N. meridionalis_, Costa. Naples, Ischia, Sestri near Genoa,
Mentone, and Cannes.]
[_N. Eleanora_. Mentone and Cannes.]
_N. cellicola_, Sav. et Aud. Rome, Sicily, and Egypt.
_N. maculatipes_, Doleschall. Sardinia.
_N. badia._, Auss. Corsica.
_N. manderstjernæ_, L. Koch. Nice.
_N. hispanica_, L. Koch. Madrid.
_N. macrocephala_, Auss. Palermo.
_Brachythele icterina_, C. Koch. Greece.
_B. incerta_, Auss. Brussa.
_Macrothele calpetana_, Walck. Southern Spain.
_M. luctuosa_, Luc. Southern Spain.
_Leptopelma transalpina_, Doleschall. Friuli.
_Ischnocolos triangulifer_, Doleschall. Sicily.
_I. holosericeus_, L. Koch. Spain.
_I. gracilis_, Auss. Cyprus.
_I. syriacus_, Auss. Syria.
_Chætopelma ægyptiaca_, Dol. Egypt.
D.
_Hints on Collecting Spiders._
It is very important to collect adult specimens of males and females,
but the former, from their roaming habits, are often extremely
difficult to find.
At night they may sometimes be taken by lamp-light near the nests
of the females, and certain kinds are said to live with the female
during the months of September and October. The females may usually
be found in their nests during the daytime (always in Europe?).
Large spiders should be killed, or at least stupefied with
chloroform, before being put into spirit of wine. It is convenient to
place the specimens in glass test-tubes closed with corks, and filled
with pure spirit of wine, as they may then be examined through the
glass.
When specimens of more than one species are placed in the same
tube or bottle, it is well to distinguish each by a number written
in pencil on a small strip of card fastened round the body with a
slip-noose of thread.
The patterns on the abdomen and cephalothorax of the spiders are seen
very distinctly when the spiders are immersed in spirits of wine,
and these frequently afford characters which aid in determining the
species.
M. Thorell, in the introduction to his work _On European
Spiders_,[100] gives a detailed account of a method by which
specimens may be prepared for mounting in cabinets, by drying them
within a glass tube held over a flame, but it would appear that, for
purposes of study, specimens preserved in spirit of wine are far
preferable.
[Footnote 100: Thorell (T.), On European Spiders, in Nova Acta Regiæ
Societ. Scientiar. Upsaliensis, ser. 3, vol. viii. fasc. I. et II.
(Upsala, 1871).]
It is very desirable to obtain characteristic portions of, or
if possible entire nests, but where the tubes are long, this is
extremely difficult to do satisfactorily.
Some nests, preserved in the British Museum, have been coated with
thin glue, and this appears to be of some use in binding the parts
together. I find that by stuffing the tube full of cotton-wool,
before attempting to remove the earth, the nest may sometimes be
obtained in tolerably good condition.
E.
_The Nest of the Tarantula (Lycosa Tarentula)._
As it is of some interest to compare the burrow of the Tarantula
with the nest of its near allies the trap-door spiders, I give the
following _résumé_ of M. Dufour's observations:[101]--
[Footnote 101: Quoted by M. Lucas, in his Histoire Nat. des Animaux
Crustacés et Arachnides, p. 357.]
"_Lycosa Tarentula_ forms a cylindrical burrow in the earth, often
more than a foot long, and about one inch in diameter. At about four
or five inches below the surface the perpendicular tube is bent
horizontally, and it is at this angle that the Tarantula watches for
the approach of enemies or prey.
"The external orifice of the burrow of the Tarantula is ordinarily
surmounted by a separately constructed tube, and which authors have
not hitherto mentioned; this tube, a true piece of architecture,
rises to about an inch above the surface of the ground, and is
sometimes as much as two inches in diameter, being thus larger than
the burrow itself. This tube is principally composed of fragments
of wood fastened together with clayey earth, and so artistically
disposed one above the other that they form a scaffolding having
the shape of an upright column, of which the interior is a hollow
cylinder."
M. Dufour observes, however, that the exterior tube was not found in
all the nests. In every case the tube was lined with silk throughout
its whole length.
F.
The following description is that given by Prof. Ausserer in his
monograph of _Territelariæ_,[102] of a male trap-door spider
which was found at Nice, and named by Herr L. Koch _Nemesia
Manderstjernæ_. It is just possible, I think, that this male may in
reality belong to _N. meridionalis_ [Costa-Cambr.], of which the
female alone is at present known.[103] If this is the case, then the
name _Manderstjernæ_ will have to be suppressed in favour of that of
_meridionalis_. If not, we have yet to discover the female spider and
nest of another species of _Nemesia_!
[Footnote 102: Beiträge zur Kenntniss der Arachniden-Familie der
Territelariæ, in Verhand. der k. k. zool.-bot. Gesellschaft in Wien
(1871), vol. xxi. p. 170.]
[Footnote 103: Mr. Pickard-Cambridge regards this suggestion (that
_N. Manderstjernæ_ may be the male of _N. meridionalis_) not
improbable.]
5. _Nemesia Manderstjernæ_, L. Koch.
♂ Die genaue Beschreibung dieser hübschen Art ihrem Autor, Herrn
Dr. L. Koch überlassend, führen wir hier nur jene wesentlichen
Unterscheidungsmerkmale an, welche diese Species von den verwandten
auszeichnen.--Cephalothorax schön gerundet mit schmalem, mässig hohem
Kopfe.--Augenhügel hoch, nach vorn und hinten steil abfallend.--Die
vordere und hintere Augenreihe bilden 2 nahezu parallele Curven,
mit der Concavität nach vorn. Vordere Mittelaugen stehen so hoch,
dass eine Gerade von ihrer Basis zu den Seitenaugen gezogen etwas
über denselben zu stehen käme, zugleich sind sie von einander
um ihren Radius und kaum weiter von den vorderen Seitenaugen
entfernt. Augen der vorderen Reihe fast doppelt so gross als
die der hinteren.--Zähne des Rechens lang und spitz.--Palpen
mässig lang, letztes und vorletztes Glied ähnlich bewaffnet wie
bei _N. cellicola_.[104]--Bulbus birnförmig, mit etwas kurzer,
dünner Spitze.--Alle Tarsen der Beine, ebenso Metatarsus I und
II mit dünner Scopula, zugleich sind die Tarsen wehrlos.--Tibia
I keilförmig verdickt, unten an der Spitze ein starker nach
oben und innen gebogener, spitzer Zahn, vor demselben ein oben
gerade abgestutzter Höcker.--Schenkel oben und innen mit dunkelm
Längsstreifen.--Cephalothorax 6·5^{mm}.
[Footnote 104: Description of palpi of _N. cellicola_, p. 168:
"Palpen kurz, stark. Femuralglied oben bestachelt; vorletztes Glied
oben an der Spitze mit 4 starken, etwas kurzen Stacheln, auch das
Endglied nach oben mit sehr kleinen Stacheln bewaffnet. Bulbus kurz
birnförmig, in eine feine, mässiglange, fadendunne (vorn nicht
gespaltene) Spitze auslaufend."]
Nizza.
Of this description the following is, I hope, a tolerably correct
translation:--
_Nemesia Manderstjernæ_, L. Koch.
♂ Passing over the precise description of this pretty species by its
author, Herr Dr. L. Koch, let us note here some of the essential
characters which distinguish this species from its relations.
_Cephalothorax_ fairly (schön) rounded, with small, moderately
prominent head. Eye eminence (Augenhügel) prominent, steeply inclined
in front and behind. The front and rear row of eyes form two nearly
parallel curves with the concavity in front. The foremost central
eyes stand so high that a line (eine Gerade) drawn from their base to
the lateral eyes would pass just above them, although they are not
separated from the lateral eyes by a distance greater than that of
their own radius. Eyes of front row almost twice as large as those of
hind row. Teeth of rake (Rechens) long and sharp. _Palpi_ moderately
long, the last and penultimate joint armed as in _N. cellicola_.[105]
Bulb pear-shaped, with a rather shorter, more slender point. All the
tarsi of the legs, and even the metatarsi I and II, with a slender
scopula, although the tarsi are unarmed. Tibia I enlarged into a
wedge-shape, (having) beneath the apex a stout pointed tooth bent
upwards and inwards, in front of which (is) a truncated prominence
(ein oben gerade abgestutzter Höcker). Femur (Schenkel) (having)
dusky longitudinal stripes above within.--Cephalothorax 6·5^{mm}.
[Footnote 105: Description of palpi of _N. cellicola_:--_Palpi_,
short, strong. Femoral joint furnished with spines above; penultimate
joint armed with four stout rather short spines above the apex, the
terminal joint also having some very small spines. Bulb shortly
pear-shaped, running out into a fine, moderately long point, which is
slender as a thread, and not split in front.]
Nice.
G.
_On Nemesia meridionalis and N. Eleanora, Captive in Company with
their Young._
I have tried the experiment of keeping specimens of _Nemesia
meridionalis_ and _N. Eleanora_ captive in flower-pots, partly
filled with earth and covered with gauze, but I have never been
able to detect the least inclination on the part of either of these
spiders to excavate a burrow in the earth.
Thinking that I might have better success if I were to place the
mother spiders, together with their young, in captivity, I captured a
female _N. meridionalis_ and _N. Eleanora_, each with its brood, and
placed them on moist earth in flower-pots under gauze. The result,
however, was that the young spiders concealed themselves in the
crevices of the soil, while the mother spiders remained exposed.
The adult _N. meridionalis_ lived thus for twenty days (from the 7th
to the 27th of November), capturing and killing flies with which I
supplied her, but she then suddenly died.
After seventeen days' captivity the other species (_N. Eleanora_)
began to cover a small surface of the gauze with a semi-transparent
substance (which resembled varnish rather than silk), secreted from
its spinners, and four days later it began to weave a cell; this
cell took twelve days to complete, and finally assumed the shape of
a rudely-formed figure of 8, with a circular aperture at either end,
each of which was kept open during the construction of the cell, and
then closed. The gauze itself, covered with silk, formed the ceiling
of the cell, while the floor was made of silk attached to the earth,
and the sides of strong and rather opaque silk.
This cell bore no resemblance to any portion of any trap-door
nest that I have ever seen, and it is difficult to conceive how
the idea of such a structure presented itself to the spider. Its
outline indeed had some likeness to the general outline of the
spider herself, one loop of the figure 8 being rather smaller than
the other. The distance between the floor and the ceiling of this
impromptu cell was a little over half an inch, its width varying from
one inch in the broadest to eight lines in the narrowest part, while
its length was an inch and a quarter.
It would appear that the object which the spider had in view
was to construct a warm and secure retreat for the winter, and
accordingly after having completed this chamber, she no longer made
excursions to catch the flies with which I supplied her, but remained
self-immured in her cell.[106]
[Footnote 106: My observations on the captive spider were still in
progress at the time of going to print, so that the above notes must
be considered as incomplete.]
It would be interesting to discover whether any of the spiders of
this group (but which do not construct trap-door nests) pass the
winter in similar structures.
H.
_On the Structure of Cork Doors._
In order to test my theory to the effect that the trap-door nests are
enlarged from time to time, and that the numbers of layers of silk in
an undisturbed cork door should represent the number of enlargements
which the nest has undergone, I examined the doors of twenty-eight
nests of the cork type (all I believe of _N. cæmentaria_), in order
to prove whether as a rule the larger cork doors do contain more
layers of silk than the small ones, as they should on this hypothesis.
This is, I think, fairly established by the following table:--
_Comparative Table._
One cork door measuring 1 line across contained 1 layer of silk.
Four " doors " 1-1/2 lines " 3 layers "
One " door " 1-1/2 " 2 "
One " door " 1-3/4 " 4 "
One " door " 2 " 5 "
Two " doors " 2-1/2 " 6 "
One " door " 2-1/2 " 5 "
One " door " 3 " 8 "
Two " doors " 3-1/2 " 5 "
One " door " 3-1/2 " 7 "
One " door " 4 " 7 "
Two " doors " 4-1/2 " 8 "
One " door " 4-1/2 " 7 "
Two " doors " 5 " 9 "
One " door " 5 " 5 "
One " door " 5 " 6 "
One " door " 5 " 13 "
One " door " 5-1/2 " 9 "
One " door " 5-1/2 " 10 "
One " door " 5-1/2 " 14 "
One " door " 6 " 12 "
The apparent exceptions to this rule, in which the larger doors have
fewer layers than some of the smaller ones, may probably be accounted
for in the following manner.
During the heavy rains and in times of drought flakes of earth often
become detached from the sloping banks, and carry away the doors of
such nests as are found in them.
This happens frequently, and the spiders hasten to repair the damage
and spin new doors.
But I have found, on examining eight of these new doors, that, even
in large nests,[107] they do not then contain more than three layers
of silk; so that each time a nest of any size loses its door, the
number of layers is greatly reduced.
[Footnote 107: Of the eight doors in question the smallest measured
3-1/2 lines across, and the largest 7 lines.]
In the case of six of these nests I had myself acted the part of the
landslip and removed the existing door. These original and apparently
undisturbed doors measured 3-1/2, 4, 5, 5, 5, and 5 lines across, and
contained respectively 5, 7, 8, 13, 9 and 5 layers of silk; while
of the equally large doors which replaced them five contained three
layers of silk only, and the remaining nest but a single layer.
INDEX.
PART I.--HARVESTING ANTS.
Ælian on harvesting ants, 7-9.
Aldrovandus, radicle of seed gnawed by ants, 9.
Algiers, harvesters observed in, 52.
Aphides and cocci not sought by harvesting ants, 48.
Atta _barbara_, 15, &c.;
_barbara_ var., 16, 31, 63;
_barbata_, 12;
_cephalotes_, 13;
_diffusa_, 12 (note), 65;
_megacephala_, 16, working at night, 49;
_providens_, 12 (note), 65;
_rufa_, 12 (note), 64;
_structor_, 16, 29, 63, working at night, 49.
Battles of ants between different colonies of the same species, 37, 40;
with caterpillar, 41.
Capri, harvesting ants at, 68.
Captive ants, 42-49.
Crematogaster _scutellaris_, 62;
_sordidulus_, 63.
Dispersal of seeds by means of ants, 4, 21, 53, 55.
Distribution of harvesting ants, 52, 57, 59.
Enemies of the ants, 56.
Formica _cruentata_, 37, 61;
_cursor_, 62;
_emarginata_, 61, working at night, 49;
_erratica_, 37, 62;
_fusca_, 51, 61;
_marginata_, 62;
_nigra_, 5 (note);
_nigerrima_, 52;
_viatica_, 52.
Galls found in ants' nests, 36.
Germination of seeds arrested by ants, 20, 25, 26, 40;
this fact mentioned by Aldrovandus, 9.
Granaries, structure of, 22, 23, 31, 32, 49, 54;
position of, 31;
contents of, 27;
time required to construct, 45.
Insects inhabiting ants' nests, 35, 36, 56.
Jerdon (Dr.) on harvesting ants in India, 12, 64, 65.
Kirby and Spence, assertion that ants do not harvest in Europe, 10.
Mistakes made by ants, 19, 37.
Mouth organs of ants, 48.
Myrmica _cæspitum_, 37, 51, 63.
Occasional harvesters, 51.
Œcodoma _cephalotes_, 13;
_diffusa_, 12 (note), 65;
_providens_, 12 (note), 65.
Pheidole _megacephala_, 16, 50, 63, working at night, 49;
_pallidula_, 51, 63.
Pseudomyrma _rufo-nigra_, 67.
Radicle of germinating seeds gnawed off by ants, 20, 25, 26;
this fact mentioned by Aldrovandus, 9.
Rock nest, sandstone mined by ants, 32-35.
Rubbish heaps, materials which compose, 21, 22, 55.
Sandstone mined by ants, the rock nests, 31-35.
Seeds, dispersal of, by means of ants, 4, 21, 53, 55;
tendency to germinate arrested, 24, 50;
eaten by ants, 46-48, 54.
Seed stores of ants used as food by natives of India, 67.
Spherical chamber found in ant's nest, 35.
Sykes (Lieut.-Col.) and Jerdon (Dr.) on harvesting ants in India, 12,
64, 65.
Winged males and females of Aph. _Structor_ and _Barbara_, 41.
PART II.--TRAP-DOOR SPIDERS.
Atypus _Blackwallii_, 78.
Atypus _piceus_, 77;
nest of, 78.
Ausserer (A.), description of Nemesia _manderstjernæ_, 145.
Australia, trap-door spiders in, 114, 130.
Blackwall, on nests of Atypus _piceus_, 78 (note).
Blackwall, on the tarsi of certain spiders being furnished with a
viscous secretion, 87.
British representative of the sub-order Territelariæ, 77.
Browne (Patrick), on the trap-door spider of Jamaica, 73.
Cambridge (Rev. O. Pickard), description of Cteniza _fodiens_, 89;
of Nemesia _cæmentaria_, 92;
of N. _meridionalis_, 101;
of N. _Eleanora_, 108.
Captive trap-door spiders, 118, 122, 143.
Claws, compared in different trap-door spiders, 86;
retractile, 87 (note).
Construction of trap-door nests, 118, 122, 123, 149.
Cork nests, 80, 88, 94, 97, 116, 124, 131, 132, 141.
Costa (O. G.), on Mygale (Nemesia) _meridionalis_, 105, 137.
Cteniza _ariana_, 115, 135, 141;
_ædificatorius_, 85;
_fodiens_, 89;
_ionica_, 91;
_nidulans_, 81.
Double-door branched nest, 80, 98, 103-106, 131.
Double-door unbranched nest, 80, 98, 106, 111, 131.
Dufour (Léon), on the nest of Lycosa _tarentula_, 146.
Enemies of spiders, 101, 134.
Epeira _fasciata_, cocoon of, 76.
Erber, on the nocturnal habits of Cteniza _ariana_, 115, 135, 141.
Geographical range of species of trap-door spiders, 131, 132, 133, 143.
Gosse (P. H.), on the single-door wafer nest in Jamaica, 80-83.
Instinct (?) of nest building in very young spiders, 123, 126, 128.
Lucas (H.), on spiders having retractile claws, 87.
Lycosa _tarentula_, M. Dufour on the nest of, 146.
Male of Nemesia _Eleanora_, 109, 115.
Mygalidæ, name changed to Territelariæ, 75.
Nemesia _cæmentaria_, 73, 92, 97, resisting when the door is touched,
94-96;
_cellicola_, 141, 147, 148;
_Eleanora_, 98, 106, 108, 112;
_Manderstjernæ_, 147;
_meridionalis_, 98, 101, 137.
Nest of Lycosa _tarentula_, 146.
Nocturnal habits of trap-door spiders, 115, 116.
Olivier, on cork nests at Hyères, 115.
Rossi (P.), on Cteniza _fodiens_, 73.
Resistance of spiders when doors are touched, 94-96, 100, 112.
Saunders (S. S.), on Cteniza (_Mygale_) _ionica_, 91, 122.
Sauvages (Abbé), on Nemesia _cæmentaria_, 73.
Selection of materials for trap-doors, 119, 120.
Sells (W.), on the nest of Cteniza _nidulans_, 83.
Single-door wafer nests, 80, 131.
Tarsi of spiders furnished with a viscous secretion, enabling them to
traverse perpendicular polished surfaces, 87.
Territelariæ a sub-order of Araneæ, formerly called Mygalidæ, 75.
Territelariæ, species of, inhabiting the Mediterranean region, 130, 131,
133, 143.
Theridion, cocoon of, 77.
Trap-door nests enlarged not abandoned, 123, 127, 150.
Walckenaer (C. A. de) on habits of trap-door spiders, 114, 117;
on structure of cork doors, 125 (note).
Wallace (A. R.) on the philosophy of birds' nests, 129.
West Indian nests of the single door wafer type, 80.
Westwood (Prof.) on the nest of Cteniza _ædificatorius_, 85.
Young spiders found in nests of Nemesia _meridionalis_ and N.
_Eleanora_, 112.
* * * * *
Transcriber's Note
Minor typos corrected. Text rearranged so that illustrations will not
split paragraphs. For a number of species that list a pair of alternate
Genera in italics with an unitalic "or" between them in the text, the
italics markup includes the "or".
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