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).