Chapter I: Front Matter (1)

Supplement to Harvesting Ants and Trap-door Spiders.

J. Traherne Moggridge

Transcriber's Note: Text emphasis denoted as _Italic_ and =Bold=. Whole numbers and fractional parts as 123-4/5.

SUPPLEMENT

TO

HARVESTING ANTS

AND

TRAP-DOOR SPIDERS.

SUPPLEMENT
TO
HARVESTING ANTS
AND
TRAP-DOOR SPIDERS.

BY
J. TRAHERNE MOGGRIDGE, F.L.S., F.Z.S.

_WITH SPECIFIC DESCRIPTIONS OF THE SPIDERS,_

BY THE

REV. O. PICKARD-CAMBRIDGE.

LONDON:
L. REEVE & CO., 5, HENRIETTA STREET, COVENT GARDEN.
1874.

LONDON:
SAVILL, EDWARDS AND CO., PRINTERS, CHANDOS STREET,
COVENT GARDEN.

CONTENTS.

PAGE
SUPPLEMENT TO HARVESTING ANTS 157

SUPPLEMENT TO TRAP-DOOR SPIDERS 180

SPECIFIC DESCRIPTIONS OF SPIDERS 254

EXPLANATION OF PLATES.

Plate XIII., p. 183, fig. A.--Silk lining of tube of _Atypus
piceus_ (Sulz.), taken at Troyes in Champagne, and
communicated to me by M. E. Simon; B, drawing of portion
of nest of _Cyrtauchenius elongatus_ (Sim.) made after the
description of the discoverer, and subject to his (M. E.
Simon's) corrections. This is the only illustration in the
present work not taken from an actual specimen. These figures
are of the natural size.

Plate XIV., p. 193.--Diagrams of the known types of trap-door nest.
Fig. A, nest of _Atypus piceus_ (Sulz.); B, nest of cork
type; B 1, the layers of silk with earth rims of which a cork
door is composed; C, single-door unbranched wafer type; D,
single-door branched wafer type; E double-door unbranched
wafer type; E 1, lower door of the same, of the natural size;
F, Hyères double-door branched wafer type; F 1, lower door
of the same, of the natural size; G, and G 1, double-door
branched cavity wafer type. At G 1 the perfect type is seen,
while at G, the descending cavity, the outlines of which are
indicated by dotted lines, has been filled up; G 2, lower
door of the same of the natural size. (Figs. A, B, C, D,
E, F, G and G 1, diagrammatic representations of nest on a
reduced scale, Figs. B 1, E 1, F 1 and G 2, of the natural
size).

Plate XV., p. 198, fig. A.--Nest of _Cteniza Californica_ (Camb.)
nearly entire, enclosed in the clayey earth of the bank from
which the specimen was taken, the door being artificially
represented as being partly open; A 1, door of the same as
seen when closed; B, _Cteniza Californica_ (Camb.) from a
living specimen; B 1, the same seen in spirits, the legs not
represented; B 2, the same seen sideways; (figs. A, A 1, B, B
1 and B 2, are of the natural size); B 3, the eyes, greatly
magnified; B 4, the three claws terminating the tarsal joint
of the hindmost left leg; B 5, line representing the measured
length of the spider excluding the falces and spinners, the
uppermost division gives the length of the caput terminating
at the half-moon-shaped fovea, the middle division that of
the thorax, and the lowest that of the abdomen, while the
transverse line gives the breadth of the cephalothorax; B 6,
eggs laid by the spider in captivity on the under side of the
gauze which covered the box (the position is reversed here)
of the natural size; B 7, the same magnified; B 8, another
group of eggs, magnified; B 9, a portion of the same still
more highly magnified; B 10, lines showing measured lengths
of legs of the 1st, 2nd, 3rd, and 4th pairs, and of palpus,
with those of the several joints.

Plate XVI., p. 211, fig. A.--Part of the nest of _Nemesia Simoni_
(Camb.) taken at Bordeaux; A 1, _N. Simoni_ (Camb.) from
life, of the natural size; A 2, the same seen in spirits,
the legs not represented; A 3, the same seen sideways and
magnified; A 4, the eyes, magnified; A 5, the thoracic fovea,
magnified; A 6, line showing measured length of spider, (see
above explanation of fig. B 5, plate XV.); A 7, lines showing
measured lengths of legs of the 1st, 2nd, 3rd, and 4th pairs,
and palpus of spider, with those of the several joints. B,
cephalothorax and abdomen of another specimen of _N. Simoni_,
in which the proportions are different, taken from life, of
the natural size.

Plate XVII., p. 215, fig. A.--Part of the nest of _N. suffusa_
(Camb.) taken at Montpellier; A 1, _N. suffusa_ (Camb.)
from life, of the natural size; A 2, the same in spirits,
seen sideways and magnified, the legs not represented; A
3, another view of the same; A 4, the eyes, magnified; A
5, length of spider (see above, fig. B 5, plate XV.); A 6,
measurements of legs and palpus; B, _N. meridionalis_ (Costa
and Sim.), male, from a specimen in spirits, of the natural
size, legs not represented; B 1, the same magnified; B 2, the
eyes, magnified; B 3, radial and digital joints of the left
palpus with bulb, magnified; B 4, another view of the same,
magnified; B 5, back view of the same, magnified, but less
highly; B 6, length of spider (see above, fig. B 5, plate
XV.); C, _N. meridionalis_ (Costa and Sim.) female, from a
specimen in spirit of wine, of the natural size, legs not
represented; C 1, eyes of the same, magnified; C 2, length of
spider. These two specimens (male and female) were collected
in Corsica, and named by M. E. Simon, who kindly presented
them to me; they are now in the possession of the Rev. O.
Pickard-Cambridge.

Plate XVIII., p. 225, fig. A.--Part of nest of _N. congener_
(Camb.) taken at Hyères; A 1, lower door of this nest viewed
from above, of the natural size; A 2, side view of the same;
A 3, _N. congener_ (Camb.) taken from life, of the natural
size; A 4, side view of the same, enlarged to twice the
natural size, the legs not represented; A 5, cephalothorax
and falces from specimen in spirits, magnified;[108] A 6, the
eyes, magnified; A 7, femur, patella (or genual joint) and
tibia of leg of third pair, showing the three spines on the
outer side of the patella, magnified. B, lower door from a
smaller and younger nest, viewed from above, of the natural
size; B 1, the same viewed sideways.

[Footnote 108: While these pages were passing through the press (Hyères, Oct. '74), I have had an opportunity of examining 17 additional specimens of _N. congener_. I learn from this that the pattern represented on the caput in fig. A 5, does not accord with that in the majority of adult specimens, being usually less defined and composed of three converging bands. Mr. Pickard-Cambridge's description (p. 293 below) is, however, quite correct. I may mention that three spines were present on the patella (genual joint) of legs III in 16 specimens, the 17th specimen having but a single spine.]

Plate XIX., p. 229, fig. A.--Nest of a young specimen of _N.
Manderstjernæ_ (Ausserer = _N. meridionalis_ Camb., in "Ants
and Spiders," p. 101) from Mentone, showing the descending
cavity, with the lower door pushed across, so as to close
the main tube and join the cavity; A 1, upper portion of
the same, showing the lower door closing the branch. B,
_N. cæmentaria_ (Latr.) from a living specimen taken at
Montpellier; B 1, the same seen in spirits of wine, legs not
represented; B 2, the eyes, magnified; B 3, one of the two
larger claws; and B 4, the small claw of the tarsus of one of
the hindmost legs; B 5, length of spider; B 6, measurements
of legs and palpus. C, the eyes of _N. Moggridgii_ (Camb.)
(= _N. cæmentaria_, Camb., in "Ants and Spiders," p. 92),
magnified. D, _N. incerta_ (Camb.), male, from a specimen
preserved in spirits, collected at Digne in the Basses
Alpes, by M. E. Simon, who kindly lent me the specimen for
examination, represented of twice the natural size, and
without the legs; D 1, another view of the same; D 2, radial
and digital joints of the palpus and palpal bulb, magnified;
D 3, back view of the same; D 4, the eyes magnified. E, eyes
of _N. dubia_ (Camb.), male (= _N. cæmentaria_, Sim.), from
a specimen in spirits, collected in the Pyrénées Orientales,
communicated by M. Simon, magnified; E 1, radial and digital
joints of the palpus with palpal bulb of the same, magnified;
E 2, another view of the same.

Plate XX., p. 254, fig. A, _Cteniza Moggridgii_ (Camb.), male (=
_Ct. fodiens_, Camb., in "Ants and Spiders," p. 89), from
a living specimen taken at Mentone, of the natural size; A
1, the same seen sideways, the legs not represented; A 2,
cephalothorax and falces of the same; A 3, the eyes; A 4,
radial and digital joints and the palpal bulb; A 5, another
view of the same; A 6, one of the two large claws, and A
7, the small claw of the tarsus of one of the legs of the
hindmost pair; A 8, length of the spider and breadth of the
cephalothorax; A 9, measurements of legs and palpus. (Figs.
A 1, A 2, A 3, A 4, A 5, A 6, and A 7, are all magnified.)
B, _N. Manderstjernæ_ (Ausserer), male (= _N. meridionalis_,
Camb., in "Ants and Spiders," p. 101), from a living specimen
taken at Mentone, of the natural size; B 1, the same seen in
spirits and magnified to twice the natural size; B 2, the
same viewed sideways; B 3, the eyes; B 4, tibia, metatarsus
and tarsus of the right leg of the first pair showing the
spine and process on the under and inner side of the enlarged
tibia; B 5, right leg of the third pair showing the three
short spines on the patella; B 6, one of the two large claws,
and B 7, the small claw of the tarsus of one of the legs of
the hindmost pair; B 8, radial and digital joints of palpus
with palpal bulb; B 9, another view of the same; B 10, back
view of the same (figs. B 1 to B 10, all magnified); B
11, measurements of legs and palpus. C, tibia, metatarsus
and tarsus of right leg of _N. Manderstjernæ_ (Ausserer),
male, viewed from the under side and magnified, drawn from
the original specimen belonging to Dr. L. Koch, collected
at Nice, and described as _N. Manderstjernæ_ by Professor
Ausserer. My best thanks are due to Dr. L. Koch for having
enabled me to examine this valuable specimen. [In fig. C,
the curved spine should bend towards, and not away from, the
process on its right and inner side.]

LIST OF SPIDERS DESCRIBED.

Cteniza Moggridgii, sp. n. ♂ p. 254, pl. XX. fig. A.
" Californica, sp. n. ♀ p. 260, pl. XV. fig. B.
Nemesia cæmentaria (Latr.) ♀ p. 264, pl. XIX. fig. B.
" Eleanora (Cambr.) p. 272.
" Moggridgii, sp. n. ♀ p. 273, pl. XIX. fig. C.
" incerta, sp. n. ♂ p. 276, pl. XIX. fig. D.
" dubia, sp. n. ♂ p. 280, pl. XIX. fig. E.
" Manderstjernæ (Auss.) ♂ and ♀ p. 283, pl. XX. fig. B.
" meridionalis (Costa) ♂ and ♀ p. 289, pl. XVII. fig. B.
" congener, sp. n. ♀ p. 292, pl. XVIII. fig. A 3.
" suffusa, sp. n. ♀ p. 295, pl. XVII. fig. A 1.
" Simoni, sp. n. ♀ p. 297, pl. XVI. fig. A 1.

SUPPLEMENT TO HARVESTING ANTS.

During the short time which has elapsed since _Harvesting Ants and Trap-door Spiders_ left the printer's hands, fresh material has rapidly accumulated, and an assiduous search after these creatures, and the continued study of their works and ways, has met with ample reward and encouragement.

It was my wish, when originally publishing these observations, many of which were due to the active co-operation of friends, to invite my readers to take part with me in my pleasure and pursuits, so that we should from that time work together, and, by communicating our discoveries to each other, increase our knowledge, and at the same time enlarge the field of our research. My intention was that we should leave to others the necessary work of collection, preservation, and arrangement, and that, while our fellow naturalists pin specimens into classified cabinets, and devote long hours to the description of peculiarities of form and colour, we should undertake the lighter task of complementing their labours by observing and recording the habits and conditions of existence of the creatures themselves.

Looked at in this light, the present pages and those of the preceding work may be regarded as so many drawers in our _Cabinet of Habits_, and though, as we open drawer after drawer, many gaps and blank spaces remind us how much remains to be done in order to complete the collection, yet the interest and suggestiveness of the specimen-facts already secured, should encourage and direct us onwards. There have not been wanting instances in which my readers have associated themselves with me in the way indicated, and it is with pleasure, when reviewing the entire work, that I recall how many of its most interesting features are due to the researches and assistance of friends,[109] and commemorate at once their discoveries and unfailing kindness. I had certainly expected that before this time some new species of harvesting ants would have been discovered, either on the Riviera, where attention has been especially called to the subject, or in other parts of Europe, where dissimilar conditions might have been expected to be associated with a different fauna; but this has hitherto not been the case.

[Footnote 109: To all who have rendered me this valuable help I tender my cordial thanks. I am under very special obligations to Mr. Pickard-Cambridge, for descriptions of spiders, and to Mr. F. Smith for the names of the Ants; assistance which I should have found it almost impossible to dispense with or to replace.]

One might naturally suppose that if harvesting ants were discovered in localities very widely distant from each other, they would prove to belong to different species, but thus far, both in Europe and Northern Africa, it is the same two well-known species of _Atta barbara_ and _A. structor_ that constantly reappear.

For instance, I have recently learned that harvesting ants are found at Cadenabbia on the lake of Como, and at Montpellier in Southern France; but on examination, the ants from the former place are clearly seen to belong to the species _structor_, and those from Montpellier to the two species _structor_ and _barbara_.

I was greatly interested to receive specimens of ants, and of the seeds which they were carrying and storing beneath the stones of a paved road at Cadenabbia, for this is the northernmost point[110] at which the habit of harvesting has as yet been noted. This discovery suggests the possibility of the occurrence of the habit in the warmer and more sheltered of the Swiss valleys. When at Montpellier in May last I frequently observed long trains of ants bringing seeds and small dry fruits to their nests, but these harvesters also turned out on close inspection to be _Atta structor_ and _A. barbara_, with its red-headed variety. These, it will be remembered, are the only species of European ants which have as yet been proved to be harvesters and seed-storers in the fullest sense of the term, that is to say, which not only gather and carry seeds, but also store them in large quantities below the surface of the ground.[111]

[Footnote 110: I have related in a note at the foot of p. 4 in _Ants and Spiders_ how _Formica nigra_ in England, though paying no attention to seeds generally, will sometimes collect the fresh seeds of the sweet violet (_Viola odorata_).

When I published this account I was quite unaware that the fact that certain English ants collect sweet violet seeds had been observed by Mr. R. Wakefield forty years before.

This was communicated by Mr. Wakefield in a letter to Mr. John Curtis, the substance of which was read before the Linnean Society in 1854, and published in their Proceedings (see Proceedings of the Linnean Society, ii. 293), where we read: "He (Mr. Wakefield) states that he has seen the black species (_Formica nigra_, L.) for days and nights together industriously occupied in dragging to its cells the seeds of the common violet (_Viola odorata_, L.)

"He first noticed this fact on the 3rd of July, 1832; and he regards it as a curious subject of inquiry for what purpose, if not for their own future provision, they could accumulate these stores?" Mr. Wakefield appears to accept this as evidence that these ants possess the habit of storing seeds; but this is not so, as will be seen by reference to my note alluded to above, and I am inclined to believe that they collect these particular seeds either under the mistaken belief that they are larvæ, to which when fresh they bear some resemblance, or for the sake of some juices which they may obtain from the fleshy appendage attached to the seed.]

[Footnote 111: Six other species belonging to the genus _Atta_ are found in Europe, but they are all unknown to me.

It seems likely that, if other harvesting ants do exist in Europe they may belong to one of these six species; for we have seen (_Ants and Spiders_, p. 59) that all the ants which are known to possess this habit are either members of the genus _Atta_ or belong to genera closely related to it.]

In the case of _Pheidole megacephala_ (the only other European ant which I have detected collecting seeds in large numbers), I have never been able to find granaries or subterranean stores of any kind, though I have frequently made extensive search for them, and explored, to all appearance, the whole nest.

When we remember the great variety of ants which inhabit Europe alone (a recent list[112] enumerating no fewer than 104 distinct species), it certainly may seem strange at first that only two of their number should possess this habit. Perhaps, however, we may yet discover that some other of these species are true harvesters; but at present the chances seem rather against it, since the harvesters found at such distant points as Algiers, Cadenabbia, and Montpellier have all turned out to belong to one or other of the two species, _structor_ or _barbara_.

[Footnote 112: _Description des Fourmis d'Europe pour servir à l'étude des insectes myrmecophilis_, by Ernest André, in _Rev. et Mag. de Zool._ 3^{e} ser. tom. ii. (1874), p. 152, &c.]

Indeed it may very well be that the numerical superiority and wide distribution of these two species have served to secure to them a more or less exclusive right to the habit of harvesting, for it is clear that a given tract of country can only afford supplies of grain to a limited number of colonies; so that, if these ants have taken up the ground and are strong enough to maintain possession, no others would have a chance. However this may be, I find that the more insight I gain into the distinctive habits and relations of animals, the more the belief impresses itself upon me that wherever we find many closely-allied species inhabiting restricted areas, there we may safely look for important differences among these species in respect of their modes of life, and in the development of their instinct and intelligence. And indeed this may be considered as a corollary of the great law of natural selection, which uniformly tends to secure the greatest possible amount of divergence in this respect, and to prevent the co-existence in close proximity to each other of distinct species having the same requirements and manner of life.

Thus, for example, even _Atta barbara_ and _structor_, though most closely related as species, differ in habit; the former leading a much more active life during the winter months at Mentone than the latter, and seeking its home rather in wild than cultivated ground. Then what differences different ants present in respect of strength, speed, powers of offence and defence, numerical strength of colonies, timidity, date and frequency of departure of winged ants from the nest, odour emitted, combativeness, architecture and selection of localities, nature of food, nocturnal and diurnal habits, and in many other properties and conditions! It is doubtless owing to dissimilarity in these and other respects that it becomes possible for so many species to co-exist within very narrow limits, so that even three or four distinct kinds sometimes form their nests so close to each other that their galleries interlace and almost touch.

There are probably very few conditions of life (except those concerned with the nature and manner of obtaining food) which have a greater influence either in keeping creatures apart or in bringing them into collision, than those which constitute differences in their respective periods of activity and development. Thus, two species of which one has nocturnal and the other diurnal habits, or of which one is dormant while the other is active, may be said to travel different roads and to be complete strangers to one another. Complete separation of this kind is, of course, not the rule, and the greater number of species find themselves in more or less constant rivalry, but possess a sufficient number of points of dissimilarity in habit and requirements to make their co-existence possible.

It is curious to note what little differences, as they seem to us, may determine the fate of an ant. For example, the lizards will lie in wait for and greedily seize and devour the winged males and females of _structor_ and _barbara_, though they dare not attack the assembled workers. It is curious to watch the way in which these worker ants will protect the winged ants which are about to leave the nest, by gathering round and swarming over them. When, as often happens, the nest is placed in an old terrace-wall, one may see the lizards creeping along or lying moulded into the inequalities of the stones, all having their eager eyes directed towards the swarm. One may then see the worker ants walk with impunity straight up to the very noses of the lizards, while the male or female which should chance to straggle in the same direction would infallibly be eaten up. The lizards plainly show their fear of the workers by the way in which, when they make up their mind to try a dash at some outlying part of the ant colony, they leap through the lines in the utmost haste as if traversing a ring of fire.

Now these worker ants are destitute of stings, and I can only suppose that their power of combination, stronger jaws and more horny coats, have gained them this immunity. I remarked that the smaller lizards appeared to have some difficulty in dealing with the males and females which they captured, and would beat and pound them against the stones before devouring them, while the larger ones would often make but one mouthful of them, swallowing wings and all!

If it were not for this body-guard of workers it is difficult to see how the males and females in such situations could ever escape. It is also plain that if the worker harvesting ants were as liable to be seized and devoured as their winged companions, the species would soon become extinct, for they expose themselves more than ants ordinarily do, and their long provision-laden trains would be almost at the mercy of any enemy which could attack them without fear of results.[113]

[Footnote 113: Speaking of the enemies of ants, I may mention having seen a young robin in England picking up and swallowing the workers of _Formica nigra_ just as if they were crumbs. I knew that birds would eat the male and female ants, but I had thought the workers were exempt from their attacks, and, indeed, they must be so as a rule, for otherwise they would speedily become extinct.]

Remembering this, it is interesting to note how differently the tiger-beetle (_Cicendela_) behaves when hunting the powerful harvesting ants and when preying upon the weak little _Formica (Tapinoma) erratica_; for, while it seizes the latter without taking any precautions, it is evidently more than half afraid of the former.

I have seen this beetle lying in wait near a train of _structor_ or _barbara_ ants, watching until some individual separated a little from the main body, when it would rush forward and make a snap at it, retiring again as quickly as it came. If the tiger-beetle fails to seize its prey exactly behind the head it will let it go again, and two or three ants are often thus cruelly mutilated before a single one is carried off.

No doubt the beetle has learned that if once this ant clasps its mandibles upon either antennæ or legs, nothing, not even death itself, will make it release its hold. It therefore tries to pin the ant in such a way that it cannot use its formidable jaws. Perhaps the habit of forming long compact trains may have been acquired by the ants partly with a view to guarding against attacks of this kind.

The colonies of the little _F. erratica_, on the other hand, apparently have to trust to their habit of working under the covered ways which they construct, as well as to their activity and great numbers for their preservation.

I had thought that the very powerful, and, to me, disagreeable, odour of these little ants might have rendered them distasteful to the tiger-beetle, but this is evidently not the case.

I have said above that, as far as our present knowledge goes, only two out of the 104 species of European ants are possessed of the habit of collecting and storing seed, and it may be reasonably asked how it can have come about, if this is the case, that the ancient authors were so well acquainted with the fact.

The explanation is that these writers lived on the shores of the Mediterranean, where these two species--_Atta barbara_ and _structor_--are extremely common objects, both on account of their abundance and their habits. The long trains of harvesters remain exposed to view for hours together, and _structor_ seeks the neighbourhood or even the interior of towns, so that these ants arrest the attention even of the unobservant, and often become familiar as the sparrows.

There can be little doubt that these two ants display the same habits throughout all the warmer districts which they inhabit, but whether they do so in Switzerland, Germany, Northern France, and the other colder portions of their range, remains one of the many interesting questions which still await investigation.

Mr. F. Smith has recorded the presence of _Atta barbara_ in Palestine, and I have lately obtained some curious evidence which goes to show that harvesting ants not only carried on their operations in times past in that country, but that their seed-stores were on a much larger scale than any I have observed on the Riviera.

I am indebted to Dr. F. A. Pratt for the information that mention was made of ants and their stores in the Misna, that codification of the traditionary and unwritten laws of the Jews, which was commenced after the birth of Christ under the presidency of Hillel, and which has at least the merit of serving as a record of a multitude of very ancient customs and observances which, but for it, would probably have long ago been forgotten.

Now it so happens that the very first section of the Misna is called _Zeraim_, and has to do with seeds and crops, and I was thus enabled, without any very prolonged search, to light upon one of the passages in question.[114] It occurs in a chapter entitled _De Angulo_ in the Latin version, treating of the _corner_ of the fields bearing crops which should be set aside for the poor, and of the rights of the gleaners, and may be freely rendered as follows: "The granaries of ants (_Formicarum cavernulæ_), which may be found in the midst of a growing crop of corn, shall belong to the owner of the crop; but, if these granaries are found after the reapers have passed, the upper part (of each heap contained in these granaries) shall go to the poor and the lower to the proprietor." And then is added: "The Rabbi Meir is of opinion that the whole should go to the poor, because whenever any doubt arises about a question of gleaning the doubt is to be given in favour of the gleaner."

[Footnote 114: "Formicarum cavernulæ in media segete proprietarii censentur; pone messores superiore parte pauperum, inferiore proprietarii. R. Meir totum pauperum esse censet, quia quod dubium est in spicelegio, spicilegium est." And to this the following explanatory note is appended: "Formicarum cavernulæ, Frumentum inibi repertum." Misna, Sect. I. Zeraim. Cap. IV. p. 25. Latine vertit et commentario illustravit Gulielmus Guisius. _Accedit_ Mosis Maimonidis _Præfatio in_ Misnam, Edo. Pocockio _Interprete_, Oxoniæ A.D. 1690.]

The intention of this very quaint bit of legislation, or rather of the ancient custom which gave rise to it, appears to have been the following; it was to settle once and for all a nice point of conscience with reference to the claims of the poor upon these ant stores. If the heaps of grain were found among the standing corn before the reapers reached the spot or while they were still at work, the proprietor might claim them without any hesitation; but, if they were discovered after the passing of the reapers, then it was conceivable that the ants, which during the whole time had never ceased their labours, might have collected some of the grain from the fallen ears of corn which lay upon the ground, and were the property of the gleaners. These grains would be those which the ants had collected most recently, and would therefore lie on the surface of each granary heap. Thus it was settled that the upper portion of each heap should belong to the poor, and the lower, that collected from the standing crop, to the proprietor.

We may perhaps laugh at the notion of critically discussing and legislating upon such a subject, and think that such a pitiful matter might have been allowed to pass among those _minima_ about which even the Jewish law need not care.

Be this as it may, it is interesting for us to learn that a custom of the kind had its place among the recognised traditions of the people, and that the harvesting ants of Syria had earned a place in these records by amassing stores of sufficient size, and so disposed as to make them worth collecting.

This reminds us of what M. Germain de St. Pierre has related (_Ants and Spiders_, p. 29) of the extent of the depredations made among the corn crops at Hyères by these ants; and doubtless other observers who have opportunities for watching the ants during the summer months might supply further confirmation.

It would be of interest to learn the extent and manner of concealment of these large stores of grain, but, during the months from October to May, I have never seen corn in any quantity in the granaries, though there was frequent evidence of its late presence in the dense masses of husks of oats and other large grain lying near the nests. In October, 1873, I found near the entrances to a nest of _structor_ a circular mound formed of this refuse, twenty-seven inches in diameter, and averaging two inches in thickness, while near other nests I have found the chinks between the stones of the terrace-wall behind which the nest lay, literally stuffed with husks. It was plain that these grains of cereals and the larger grasses had been collected during the summer. The granaries in the winter and spring contain the grains of some few of the autumnal grasses, but are principally filled with seeds of the other more abundant autumn-fruiting plants belonging to the neighbourhood.

I have now collected from the granaries of these ants the seeds or small dry fruits of fifty-four distinct species of wild plants, and on examination I find that during my stay in the south (from October to May) the seeds of the distinctively spring and summer-flowering plants are either entirely absent or are very scarce, while the great bulk of the seeds belong to plants which ripen their fruits in the autumn. Thus the grains of oats, of the large fescue and brome grasses, of quaking grasses (_Melica_), and other kinds common near the nests in May, are conspicuously absent in the winter, as are the fruits of all the sedges but one, and this one (_Carex distans_) retains its fruits till late in the autumn. Among other spring-flowering plants common near the nests, the seeds of which are also absent, I may mention violets (_Viola odorata_), poppies, (_Papaver_), certain species of _Veronica_, _Helianthemum guttatum_, _Silene quinque-vulnera_ and _Plantago Bellardi_.

Here a curious question arises--viz., What becomes of the large stores of seeds which one may still find in the nests in May, when the ants are busy pouring fresh supplies into the nest? The answer probably is, that, as the weather becomes warmer, ever-increasing calls are made by the larvæ upon the food-resources of the nest, and that old and new seeds rapidly disappear together, and all the energy and activity of the colony is needed to meet the increased demand.

Still, it would be interesting, if it were possible, to assure oneself whether this is the case; that is to say, whether the residue of the winter stores is really consumed during the summer, or whether a portion of it remains in the granaries until the following autumn. One might perhaps learn something as to this if one had an opportunity of opening a nest late in July, and before the characteristic autumn-fruiting plants had set their seed. If the granaries were then principally filled with seeds of spring-fruiting plants, and the winter seeds were almost or entirely absent, this would afford tolerably good negative evidence in favour of the latter having been eaten during the summer.

One thing is certain, and that is, that these harvesting ants do not habitually abandon their nests every year. On the contrary, while many swarms leave the nests at different seasons, a portion of the original colony, or of its descendants, still remains in the old home, and very few out of the many nests which I have watched during the past three years, and of which I have noted and mapped the positions, have been deserted. On my return to Mentone in October, 1873, I hastened to examine the nests between which war had been carried on in the previous year (_Ants and Spiders_, p. 38), and found in one case that the vanquished nest was completely lifeless and abandoned, while the victorious colony was remarkably thriving, and its granaries teemed with seeds. The locality occupied by the other belligerent colonies had unfortunately been built over.

I have often been asked whether I could give an approximate estimate of the quantity of seeds contained in a nest of average size, but I have hitherto felt unable to do this in a satisfactory manner. I am now in possession of more reliable data, and believe that the following calculation may be taken as a near approximation to the truth. During the spring of 1873 I removed with but very little loss the contents of two granaries from a very extensive nest of _Atta structor_, consisting principally of seeds of clover, fumitory, and pellitory. These seeds, when perfectly clean and freed from earth, weighed in the one case 4 sc. 4 grs., and in the other 5 sc. 8 grs. Now there cannot have been less than eighty such granaries in this nest, so that, if we take five scruples as the average weight of the seeds in each granary, and this, allowing for loss in collection, which we may fairly do, we should have a total weight of more than sixteen ounces, or one pound avoirdupois weight of seeds contained in the nest. But, though this mass of seeds represents the result of infinite labour on the part of the ants, each individual granary contains but an insignificant quantity, and the store-chambers often lie at great distances apart; it is therefore impossible to believe that the stores alluded to in the Misna can have been as small and scattered as these were, and we must, on the contrary, suppose them to have been both larger and more accessible.[115]

[Footnote 115: Perhaps these heaps of corn may have been piled up at the entrance to the nest, as is sometimes the case when the workers, in their eagerness to secure as much as possible of a passing harvest, bring in the supplies too fast for their companions within the nest to be able to find room for and accommodate. When this happens the seeds lie outside the nest until fresh chambers are prepared for their reception.]

The means employed by the ants to prevent the germination of the seeds contained in their granaries still remain secret, and all the experiments and investigations which I have hitherto been able to make have failed to give me the clue.

The problem to be solved is the following: Given seeds, the readiness of which to germinate has been proved, to place them in damp soil at depths varying from half an inch to twenty inches below the surface in such a manner that they shall remain there dormant, neither germinating nor decaying, for weeks and even months. These very seeds must be capable of germinating after the conclusion of the experiment.

This is what the ants do for millions of seeds, for the instances in which a few seeds appear to have sprouted within the nest in defiance of the ants, are very rare and wholly exceptional; and when after prolonged wet weather germinated seeds are seen outside the nest, it will usually be found that these have the little root cut off, and are eventually carried back into the nest and used as food. By a fortunate chance I have been able to prove that the seeds will germinate in an undisturbed granary when the ants are prevented from obtaining access to it; and this goes to show not only that the structure and nature of the granary chamber is not sufficient of itself to prevent germination, but also that the presence of the ants is essential to secure the dormant condition of the seeds.

I discovered in two places portions of distinct nests of _Atta structor_ which had been isolated owing to the destruction of the terrace-wall behind which they lay, and there the granaries were filled up and literally choked with growing seeds, though the earth in which they lay completely enclosed and concealed them, until by chance I laid them bare! In one case I knew that the destruction of the wall had only taken place ten days before, so that the seeds had sprouted in this interval.

My experiments also tend to confirm this, and to favour the belief that the non-germination of the seeds is due to some direct influence voluntarily exercised by the ants, and not merely to the conditions found in the nest, or to acid vapours which in certain cases are given off by the ants themselves.

In order to put this latter point to the test of experiment, I confined about a hundred harvesting ants (_A. structor_), with their queen and several larvæ, in a glass test-tube eight inches long and one inch in diameter, closed with a cork and filled up to within about an inch of the cork with damp sandy soil, most of which was taken from the ants' nest.

I added six peas, six cress and six millet, and then kept the tube tightly corked for nine days, only once removing the cork for a few seconds in order to sprinkle a little water on the ants, which were evidently in need of it. On the ninth day I turned out the contents of the tube and found that all the peas, millet and cress, had germinated and were growing strongly. One of the cress, however, had had its root, which lay across the gallery constructed by the ants, gnawed off; four clover seeds, which had come with the soil taken from the nest, and which had formed part of the ants' stores, had germinated also. Here the small quantity of air contained in the test-tube must certainly have become saturated with any vapour which the ants may be supposed to give off, and we cannot therefore accept this as the cause of the dormant condition of the granary seeds.

I made other experiments in which harvesting ants were imprisoned along with various seeds in small, cylindrical, closed vessels containing a little damp sand. Here the vessels were frequently rolled from side to side or shaken, during the twenty-two hours for which the experiment lasted, so as to excite the ants and make them give off such odours as they possessed, but no trace of injurious influence was produced upon the seeds, which germinated and grew normally afterwards.

At Mr. Darwin's suggestion I made a long series of experiments with formic acid, in which measured quantities, pure or diluted, were placed in a watch-glass on damp sand and surrounded by seeds, the whole being enclosed in a covered tumbler, so that the effects produced on the seeds by the vapour rising from the acid might be noted. Similar seeds were sown at the same time and in the same way, but without the acid, so as to permit of comparison. These experiments have afforded some interesting results,[116] but do not supply any positive data which might help us to discover the secret of the ants. They narrow, indeed, the area in which search can profitably be made, indicating as they do that the vapour of formic acid is incapable of rendering the seeds dormant after the manner of the ants, and showing, on the contrary, that its influence is always injurious to the seeds, even when present only in excessively minute quantities.

[Footnote 116: I hope shortly to offer these observations, together with another series of a similar nature in which my friend Mr. J. B. Andrews has taken part, to the Linnean Society.]

It appears to me now that the most promising field for experiments made with a view to clearing up this difficulty, is that afforded by the closer investigation of the phenomena of normal germination, and by a study of the conditions under which seeds remain dormant, as they are occasionally known to do, in situations which our general experience would have selected as favourable to germination.

I have good hopes, also, that when we come to know more of the habits of harvesting ants in tropical countries, and when naturalists have excavated and described their subterranean stores--a thing which has not yet been done as far as I know--we may gather fresh indications to guide us in our search.

I am puzzled to account for the fact, which I have seen stated by more than one observer in India, that the ants there have a habit of bringing out large quantities of grain and seed and laying them in heaps outside their nests at the commencement of the wet season. Dr. King, the director of the Royal Botanic Gardens at Calcutta, has told me that when in the Gwalior territory during the beginning of the rainy season, he saw heaps of seeds, principally those of a leguminous plant (_Alyssocarpus_), piled up round the entrances to the ants' nests, and that it was precisely at that time that flocks of a rock-grouse (_Pterocles exustus_) first made their appearance. They fed freely upon the seeds, and Dr. King found the crops of some of these birds, which he had shot, filled with them.

It is difficult to imagine why these Indian ants should turn out from their nests the very seeds which it had cost them so much labour to collect, and the more so as we find that these seeds are devoured by birds. It seems just possible, however, that the ants, remaining torpid during the rainy season, do not require the seeds, and know that, under these circumstances, if left in the nest, they would sprout, and choke up the galleries and granaries. Perhaps also they may have learned that a certain number of the ejected seeds will spring up and afford future harvests within easy reach of the nest.

All this, however, and especially the suggestion as to the dormant condition of the ants during the rainy season, might easily be proved or disproved by direct observation; and at present we have nothing but mere speculation to go upon.

It is curious to find that the native population in a certain part of India pay a kind of tribute to the ants, for Dr. King informs me that the Hindoos in Rajputana, a province in which the old traditions and superstitions retain especial hold, have a custom of scattering dry rice and sugar for the ants, and thus apparently recognise both their love of sweet things and their habit of collecting seeds. It may be that this custom is now little more than a meaningless rite; but in the past it probably had its origin, either in a wish to propitiate the good will and avert the destructive attacks of creatures which are the scourge and dread of entire districts, or in a sentiment of combined fear and admiration--fear of the power, and admiration of the energy, forethought, perseverance, and sense of duty to the community displayed by these marvellous insects.

That the latter feeling may have had some share in prompting this act is suggested by another custom which is stated[117] to prevail in Arabia, in accordance with which an ant is placed in the hand of a newly-born child, in order that its virtues may pass into and possess the infant.

[Footnote 117: Freytag, paragraph under the Arabic word for Ant, in his _Lexicon Arabico-Latinum_, vol. iv. p. 339, where he quotes from a local dictionary.]

Among the many curious and obscure features in the economy of ants, one of the most interesting is the occasional presence in their nests of different creatures which live among and often in harmony with them, the nature of the relations between host and guest being for the most part quite unknown.

When examining the contents of some granaries from an extensive nest of _Atta structor_ at Mentone last spring (1874), I found large numbers of a minute, shining-brown beetle moving about among the seeds. These little creatures were themselves not unlike some very small seeds, and were of an elliptic form, measuring a trifle less than one line in length. They proved to belong to the scarce and very restricted genus _Coluocera_.[118] This species, named by Kraatz _C. attæ_, on account of its inhabiting the nests of ants belonging to the genus _Atta_, has been found in Greece.

[Footnote 118: I am indebted to Mr. F. Smith of the British Museum for the name of this beetle and for the following reference to its description; Kraatz in _Berliner Entomologische Zeitschrift_ for 1858-9, p. 140.]

Mr. Bates,[119] in his most interesting account of his travels on the Amazons, remarks upon the singular fact, of which the above instance is an example: "that some of the most anomalous forms of Coleopterous insects are those which live solely in the nests of ants," and he then goes on to allude to the strange snake _Amphisbæna_, a native of that region, which also lives in the nests of the Sauba ants (_Œcodoma cephalotes_), observing how curious it is that an abnormal form of snakes should be found in the society of these insects. He is of opinion, however, that the _Amphisbæna_ is not an inoffensive guest, but lives upon the ants whose nest it selects for its home.

[Footnote 119: _Naturalist on the Amazons_, p. 61-2 (Ed. 2, 1864).]

Another remarkable inhabitant of ants' nests is a minute cricket, of which I found a single example in the midst of a colony of black ants at Mentone in February, 1874. This miniature cricket is scarcely as large as a grain of wheat, the body, excluding the antennæ and other appendages, measuring only two lines in length. It has been described by Dr. Paolo Savi[120] under the name of _Gryllus myrmecophilus_. He detected it in the nests of several species of ants in Tuscany, where it lived on the best terms with its hosts, playing round their nests in warm, and retiring into them in stormy weather, while allowing the ants to carry it from place to place during their migrations.

[Footnote 120: Dr. P. Savi, _Osservazione sopra la Blatta acervorum di Panzer_ in _Bibliotheco Italiana_, tom. xv. p. 217.]

_Gryllus myrmecophilus_ has also been observed in nests of the turf ant (_Tetramorium cæspitum_) near Paris.[121]

[Footnote 121: _Bulletin Soc. Entom. de France_ (1872), p. li.]

At Mentone I have never found more than this one specimen, and the ants among which it was domiciliated were of a species new to me (_Camponotus_ (_Formica_) _lateralis_, Oliv.). This colony of ants was composed of many winged males and females, as well as workers, the last-named measuring from two and a half to three lines in length, and black in colour. In other colonies I have found the workers black, with red head and thorax.

Another ant, not enumerated in my list in _Ants and Spiders_, is _Camponotus_ (_Formica_) _sylvatica_, which I detected in March last under stones on Cap Martin, near Mentone. When disturbed, this ant runs along with its abdomen raised vertically in the air, much as the devil's coachhorse (_Staphylinus_) does. The same curious habit of erecting the abdomen is found in another ant, not uncommon in decaying wood in the South, _Crematogaster scutellaris_; and probably all three insects adopt this threatening attitude, which is that of the scorpion preparing to strike and sting, in order to intimidate their enemies, though _Crematogaster_ is the only one which really possesses a sting.

_Camponotus sylvatica_ has the same long legs and slender body as _Formica cursor_, and is of about the same size; the workers, which are of a dark brown colour, measuring about 3-1/2 lines in length.

Perhaps it may be well, in concluding these remarks on Harvesting Ants, to call attention to the principal questions which still await solution. The first is one which any observer who travels in Central Europe during the summer may help to solve.

1. Do _any_ ants collect and store seed in Switzerland, Germany, North France, England, or indeed in any of the colder parts of the world?

2. What are the habits of _Atta structor_ and _A. barbara_ when living, as they are known to do, in Switzerland, Germany, and Northern France?

3. How do the ants contrive to preserve the seeds in their granaries free from germination and decay?

4. How are the seed-stores of tropical ants disposed below ground, and of what do they consist?

5. Do harvesting ants exist in the southern states of North America, in Australia, New Zealand, or at the Cape?

SUPPLEMENT

TO

TRAP-DOOR SPIDERS.

There would doubtless be a just feeling of pride and satisfaction in the heart of a naturalist who could say that he had made himself thoroughly acquainted with all the species of a particular group of animals, had learned their most secret habits, and mastered their several relations to the objects, animate and inanimate, which surrounded them. But perhaps a still keener pleasure is enjoyed by one who carries about with him some problem of the kind but partially solved, and who, holding in his hand the clue which shall guide him onwards, sees in each new place that he visits fresh opportunities of discovery. The latter is certainly the condition of those who take an interest in searching out the habits and characters of trap-door spiders; for this subject, far from being exhausted, expands under the light of recently acquired facts, and invites research in many parts of Europe, north as well as south.

We have only to compare the number of types of trap-door nest which were known before the publication of _Ants and Spiders_, with those at present recorded, to see how fruitful this field of inquiry has already proved.

Before this little work was published, only one type of trap-door nest was known in Europe: two new types were described in its pages, and I have now the pleasure of being able to bring three more hitherto unknown European types before the notice of my readers, thus raising the number to six in all. I do not include in these six types the very curious, and still imperfectly-known nest of _Atypus_;[122] a spider which is a true representative of the trap-door group as far as its structural characters are concerned, but which, although it excavates a silk-lined burrow in the earth, does not appear to construct any kind of door at the mouth of its tube.

[Footnote 122: See _Ants and Spiders_, page 78. _Atypus_ belongs to the sub-family _Atypinæ_, a division which does not include any of the _Nemesias_ or _Ctenizas_, and of which indeed _Atypus_ is the only European representative.]