A marauding excursion of the Amazons against the _F.

rufibarbis_, a sub-species of the _F. fusca_, or small

black ants, took place as follows:--The vanguard of

the robber army found that it had reached the

neighbourhood of the hostile nest more quickly than it

had expected; for it halted suddenly and decidedly,

and sent a number of messengers which brought up the

main body and the rearguard with incredible speed. In

less than thirty seconds the whole army had closed up,

and hurled itself in a mass on the dome of the hostile

nest. This was the more necessary as the _rufibarbes_

during the short halt had discovered the approach of

the enemy, and had utilised the time to cover the dome

with defenders. An indescribable struggle followed,

but the superior numbers of the Amazons overcame, and

they penetrated into the nest, while the defenders

poured by thousands out of the same holes, with their

larvæ and pupæ in their jaws, and escaped to the

nearest plants and bushes, running over the heaps of

their assailants. These looked on the matter as

hopeless, and began to retreat. But the _rufibarbes_,

furious at their proceedings, pursued them, and

endeavoured to get away from them the few pupæ they

had obtained, by trying to seize the Amazons' legs and

to snatch away the pupæ. The Amazon lets its jaws slip

slowly along the captive pupa, as far as the head of

its opponent, and pierces it, if it does not, as

generally happens, draw back. But it often manages to

seize the pupa at the instant at which the Amazon lets

it go and flies with it. This is managed yet more

easily when a comrade holds the robber by the legs,

and compels it to loose its prey in order to guard

itself against its assailant. Sometimes the robbers

seize empty cocoons and carry them away, but they

leave them on the road when they have discovered their

mistake. In the above case the strength of the

_rufibarbes_ proved at last so great that the

rearguard of the retreating army was seriously

pressed, and was obliged to give up its booty. A

number of the Amazons also were overpowered and

killed, but not without the _rufibarbes_ also losing

many people. None the less did some individuals, as

though desperate, rush into the thickest hosts of the

enemy, penetrated again into the nest, and carried off

several pupæ by sheer audacity and skill. Most of them

left their prey to go to the help of their comrades

when assailed by the _rufibarbes_. Ten minutes after

the commencement of the retreat all the Amazons had

left the nest, and, being swifter than their

opponents, they were only pursued for about halfway

back. Their attack had failed on account of a short

delay!

On another occasion observed by Forel, in which

several fertile Amazons also took part and killed many

enemies, the nest was thoroughly ravished, but the

retreat was also in this case very much disturbed and

harassed by the superior numbers of the enemy. There

were many slain on both sides. That in spite of the

above-mentioned unanimity different opinions among the

members of an expedition sometimes hinder its conduct,

the following observation seems to show:--An advancing

column divided after it had gone about ten yards from

the nest. Half turned back, while the other half went

on, but after some time hesitated and also turned

back. Arrived at home, it found those which had

formerly turned back putting themselves in motion in a

new direction. The newly returned followed them, and

the reunited army, after various wheelings, halts,

&c., at last turned home again by a long way round.

The whole business looked like a promenade. But

apparently different parties had different nests in

view, while others were entirely against the

expedition. Yet perhaps it was only a march for

exercise.

Outer obstacles do not, as a rule, hinder the Amazons

when they are once on the march. Forel saw them wade

through some shallow water, although many were drowned

in it, and then march over a dusty high road, although

the wind blew half of them away. As they returned,

booty-laden, neither wind, nor dust, nor water could

make them lay down their prey. They only got back with

great trouble, and turned back again to bring fresh

booty, although many lost their lives.

The following is also quoted from Büchner's excellent epitome of Forel's

observations in this connection:--

The most terrible enemy of the Amazons is the sanguine

ant (_F. sanguinea_), which also keeps slaves, and

thereby often comes into collision with the Amazons on

their marauding excursions. It is not equal to it in

bodily strength or fighting capacity, but surpasses it

in intelligence; according to Forel it is the most

intelligent of all the species of ants. If Forel, for

instance, poured out the contents of a sack filled

with a nest of the slave species near an Amazon nest,

the Amazons apparently generally regarded the tumbled

together heap of ants, larvæ, pupæ, earth, building

materials, &c., as the dome of a hostile nest, and

took all imaginable but useless pains to find out the

entrances thereinto, leaving on one side for this

investigation their only object, the carrying off the

pupæ; but the sanguine ants under similar

circumstances did not allow themselves to be deceived,

but at once ransacked the whole heap.

On another occasion, while a procession of Amazon ants was on its way to

plunder a nest of _F. fusca_, before it arrived Forel poured out a

sack-full of sanguine ants, and made a break in the nest:--

The sanguine ants pressed in, while the _fusca_ came

out to defend themselves. At this moment the first

Amazons arrived. When they saw the sanguine ants they

drew back and awaited the main army, which appeared

much disturbed at the news. But once united, the bold

robbers rushed at their foes. The latter gathered

together and beat back the first attack, but the

Amazons closed up their ranks and made a second

assault, which carried them on to the dome and into

the midst of the enemy. These were overthrown, as well

as a number of _F. pratensis_, which Forel at this

moment poured out on the nest. The conquerors delayed

for a moment on the dome after their victory, and then

entered the nest to bring out a little of the valuable

booty. A few Amazons which were mad with anger did not

return with the main army, but went on slaughtering

blindly among the conquered and the fugitives of the

three species, _fusca_, _pratensis_, and _sanguinea_.

The ravished _rufibarbes_ once became so desperate at

their overthrow that they followed the robbers to

their own nest, and the latter had some trouble in

defending it. The _rufibarbes_ let themselves be

killed in hundreds, and really seemed as though they

courted death. A small number of the Amazons also sank

under the bites of their enemies. The nest contained

slaves of the _rufibarbis_ species, which on this

emergency fought actively against their own race.

There were also slaves of the species _fusca_, so that

the nest included three different species of ants.

The same nest is often revisited many times on the

same day or at different periods, until either there

is no more to steal, or the plundered folk have hit

upon better mode of defence. A column which was in the

act of going back to such a plundered nest turned when

halfway there, and halted, apparently on no other

ground than because it had met the rearguard of the

army, and had learned that the nest was exhausted, and

that there was nothing more to be had there. The

robbers then went off to a _rufibarbis_ nest which was

in the neighbourhood, and killed half the inhabitants

while plundering the nest. The surviving _rufibarbes_

returned after the robbery and brought up new progeny;

but thirteen days later the Amazons again reaped a

rich harvest from the same nest. The Amazon army often

severs itself into two separate divisions when there

is not enough for both to do at the same spot.

Sometimes one division finds something and the other

nothing, and they then reunite. If any obstacle be

placed in their way they try to overcome it, in doing

which some leave the main army, lose themselves, and

only find their way home again with difficulty. Forel

has tried to establish the normal frequency of

expeditions, and found that a colony watched by

himself for a space of thirty days sent out no less

than forty-four marauding excursions. Of these about

eight-and-twenty were completely, nine partially, and

the remainder not at all successful. He four times saw

the army divide into two. Half the expeditions were

levelled against the _rufibarbes_, half against the

_fuscæ_. On an average a successful expedition would

bring back to the colony a thousand pupæ or larvæ. On

the whole, the number of future slaves stolen by a

strong colony during a favourable summer may be

reckoned at forty thousand!

The internecine battles which occasionally break out

among the Amazons themselves are naturally the most

cruel. They tear each other to pieces with incredible

fury, and knots of five or six individuals which have

pierced each other may be seen rolling over each other

on the ground, it being impossible to distinguish

between friend and foe. Civil wars among men are also

known to be the most embittered and the most bloody.

The mode of attack practised by the other best known species of

slave-making ant, _sanguinea_, is somewhat different:--

They march in small troops which, in case of need,

summon reinforcements, and therefore as a rule only

reach their goal slowly. Between the individual troops

messengers or scouts run continually backwards and

forwards. The first troop which arrives at the hostile

nest does not rush at it, as do the Amazons, but

contents itself with making provisional

reconnaissances, wherein some of the assailants are

generally made prisoners by the enemy, which have time

to bethink and to collect themselves. Reinforcements

are now brought up, and a regular siege of the nest

begins. A sudden invasion, like that of the Amazons,

is never seen. The besieging army forms a complete

ring round the hostile nest, and the besiegers hold

this with mandibles open and antennæ drawn back,

without going nearer. In this position they beat off

all assaults of the besieged, until they feel

themselves strong enough to advance to the attack.

This attack scarcely ever fails, and has for its chief

object the mastering of the entrances and outlets of

the nest. A special troop guards each opening, and

only allows such of the besieged to pass out as carry

no pupæ. This manoeuvre gives rise to a number of

comical and characteristic scenes. By this means the

sanguine ants in a few minutes manage to have all the

defenders out of the nests and the pupæ left behind.

This is the case at least with the _rufibarbes_, while

the rather less timid _fuscæ_ try, even at the last

moment when it is useless, to stop up or barricade the

entrances. The sanguine ants do not indeed possess the

terrible weapons and the warlike impetuosity of the

Amazons, but they are stronger and larger. If a

_fusca_ or a _rufibarbis_ fights with a sanguine ant

for the possession of a pupa, it is generally very

soon overcome. While the main part of the army is

penetrating into the nest to steal the pupæ, some

divisions pursue the fugitives, to take away from them

the few pupæ which may chance to have been saved. They

drive them even out of the cricket-holes in which they

have meanwhile taken refuge. In short, it is a

_razzia_, or sweeping burglary, as complete as can be

imagined. In the retreat the robbers in no wise hurry

themselves, for they know that they are threatened by

no danger and no loss, and the complete emptying of a

large and distant nest often takes several days in

accomplishing. The ants which have been so thoroughly

robbed scarcely ever return to their former abode.

It must be admitted that a human army, robbing a

foreign town or fortress, could not behave better or

more prudently.

Huber gives the following account of a battle waged by sanguine ants:--

At ten, in a July morning, he noticed a small band of

them emerge from their nest, and march rapidly towards

a nest of negroes, around which it dispersed. A number

of the blacks rushed out, gave battle, and succeeded

in defeating their invaders, and in making several of

them prisoners. Upon this, the remainder of the

attacking force waited for a reinforcement. When this

came up, they still declined further proceedings, and

sent more aides-de-camp to their own nest. The result

of these messages was a much larger reinforcement; but

even yet the pirates appeared to shun the combat. At

last, the negroes marched out from their nest in a

phalanx of about two feet square, and a number of

skirmishes began, which soon ended in a general

_mêlée_. Long before the event seemed certain, the

negroes carried off their pupæ to the most distant

part of the nest; and when, after a longer encounter,

they appeared to think further resistance vain, they

retreated, attempting to take with them their young.

In this, however, they were prevented, and the

invaders obtained possession of their nest and the

booty. When they had done this, they put in a

garrison, and occupied the night and the succeeding

day in carrying off their spoil.

Büchner says--

Battles between ants of the same species often end

with a lasting alliance, especially when the number of

the workers on both sides is comparatively small. The

wise little animals under such circumstances discover,

much more quickly and better than men, that they can

only destroy each other by fighting, while union would

benefit both parties. Sometimes they drive each other

out of their nests in a quite friendly way. Forel laid

on a table a piece of bark with a nest of the gentle

_Leptothorax acervorum_, and then put on it the

contents of another nest of the same species. The last

comers were by far the more numerous, and soon

possessed themselves of the nest, driving out the

inmates. But the latter did not know whither to go,

and turned back again. They were then seized by their

opponents one after the other, carried away as far as

possible from the nest, and there put down. The

oftener they came back the further were they carried

away. One of the carriers arrived in this fashion at

the edge of the table, and after it had by means of

its feelers convinced itself that it had reached the

end of the world, mercilessly let its burden drop into

the fathomless abyss. It waited a moment to see if it

had attained its object, and then turned back to the

nest. Forel picked up the ant which had fallen on the

floor, and put it down right in front of the returning

ant. The latter repeated the same manoeuvre as at

first, only stretching its neck further over the edge

of the table. He several times reiterated his

experiment, and always with the same result. Later the

two colonies were shut up together in a glass case,

and gradually learned to agree.

At other times, however, warlike ants show great and needless cruelty to

one another:--

They slowly pull from their victim, that is rendered

defenceless by wounds, exhaustion, or terror, first

one feeler and then the other, then the legs one after

another, until they at last kill it, or pull it in a

completely mutilated and helpless condition to some

out-of-the-way spot where it perishes miserably. Yet

some compassionate hearts are to be found among the

victors, which only pull the conquered to a distant

place in order to get rid of them, and there let them

go without injuring them.

The following account is also taken from Büchner's 'Mind in Animals,' p.

87:--

The doors are often guarded by special sentries, which

fulfil their important duty in various ways. Forel saw

a nest of the _Colobopsis truncata_, the two or three

very small round openings of which were watched by

soldiers, arranged so that their thick cylindrical

heads stopped them up, just as a cork stops up the

mouth of a bottle. The same observer saw the

_Myrmecina Latreillei_ defend themselves against the

invasions of the slave-making _Strongylognathus_, by

placing a worker at each of the little openings of the

nest, which quite stops up the opening either with

its head or abdomen. The _Camponotus_ species also

defend their nests by stretching their heads in front

of the openings, drawing back the antennæ. Each

approaching enemy thus receives a sharp blow or bite

delivered with the whole weight of the body. MacCook

noticed in the nests of the soon to be described

Pennsylvanian mound-building ants, the employment of

special sentries, which lay watching within the nest

entrances, and sprang out at the first sight of danger

to attack the enemy; and it was wonderful to see with

what swiftness the news of such an alarm spread

through the nest, and how the inhabitants came out _en

masse_ to meet the enemy. The _Lasius_ species defend

their large, strong, and very extensive nests against

hostile attack or sieges with equal courage and skill,

while other timid species seek to fly as speedily as

possible with their larvæ, pupæ, and fruitful queens.

There is, as Forel tells us, a regular barricade

fight. Passage after passage is stopped and defended

to the uttermost, so that the assailants can only

advance step and step. Unless the latter are in an

enormous majority, the struggle may last a very long

time with these tactics. During this time, other

workers are busy preparing subterranean passages

backwards for eventual flight. Generally such passages

are already made, and during a fight a new dome of the

_Lasius_ may be seen rising at a distance, it not

being difficult for them to make this with the help of

their extended subterranean passages and

communications.

The _F. exsecta_ or _pressilabris_ fights in a

peculiar way, which is due to care of their small and

very tender bodies. It avoids all single combats, and

always fights in closed ranks. Only when it thinks

victory secure does it spring on its enemy's back. But

its chief strength lies in the fact that many together

always attack a foe. They nail down their opponent by

seizing its legs and holding them firmly to the

ground, while a comrade springs on the back of the

defenceless creature and tries to bite through its

neck. But if threatened the holders sometimes take

flight, and so it happens that in battles between the

_exsectæ_ and the much stronger _pratenses_ not a few

of the latter are seen running about with a small

enemy clutching their shoulders, and making violent

efforts to tear the neck of its foe. If the bearer is

then seized with cramp, the nervous cord has been

injured. On the other hand, if an _exsecta_ is seized

by the back by a _pratensis_ it is at once lost.

The tactics of the turf ants resemble those of the

_exsectæ_, three or four of them seizing an opponent

and pulling off his legs. In similar fashion the

attack of the _Lasius_ species is chiefly directed

against the legs of its enemies, three, four, or five

uniting in the effort. They understand barricade

fighting particularly well in their large well-built

dwellings, and if it comes to the worst fly by

subterranean passages. They are feared by most ants on

account of their numerical superiority. Forel one day

poured the contents of ten nests of _pratenses_ in

front of a tree trunk inhabited by _Lasius

fuliginosus_ (jet ant). The siege at once began; but

the jet ants called in help from the nests connected

with their colony, and thick black columns were at

once seen coming out from the surrounding trees. The

_pratenses_ were obliged to fly, and left behind them

a mass of dead as well as their pupæ, which last were

carried off by the victors to their nests to be eaten.

Battles, however, are not confined to species of ants having warlike and

slave-making habits. The agricultural ants likewise at times wage fierce

wars with one another. The importance of seeds to these ants, and the

consequent value which they set upon them, induce the animals, when

supplies are scarce, to plunder each other's nests. Thus Moggridge

says,--

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. . . . 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 January 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.

The agricultural ants of Texas do not appear to be less pugnacious than

their European congeners. Thus MacCook says:--

A young community has sometimes to struggle into

permanent prosperity through many perils. The

following example is found in the unpublished Lincecum

manuscripts. One day a new ant-city was observed to be

located within ten or twelve yards of a

long-established nest, a distance that the doctor

thought would prove too near for peaceable

possession--for the agriculturals seem to pre-empt a

certain range of territory around their formicary as

their own, within which no intrusion is allowed. He

therefore concluded to keep these nests under close

observation, and visited them frequently. Only a day

or two had elapsed before he found that the

inhabitants of the old city had made war upon the new.

They had surrounded it in great numbers, and were

entering, dragging out and killing the citizens. The

young colonists, who seemed to be of less size than

their adversaries, fought bravely, and,

notwithstanding they were overwhelmed by superior

numbers, killed and maimed many of their assailants.

The parties were scattered in struggling pairs over a

space ten or fifteen feet around the city gate, and

the ground was strewed with many dead bodies. The new

colonists aimed altogether at cutting off the legs of

their larger foes, which they accomplished with much

success. The old-city warriors, on the contrary,

gnawed and clipped off the heads and abdomens of their

enemies. Two days afterward the battlefield was

revisited, and many ants were found lying dead tightly

locked together by legs and mandibles, while hundreds

of decapitated bodies and severed heads were strewed

over the ground.

Another example, which is given in the published

paper, is quite similar, and had like result. In

forty-eight hours the old settlers had exterminated

the new. The distance between the nests was about 20

feet. While the young colonists remained in

concealment they were not disturbed, but as soon as

they began to clear away their open disk war was

declared.

MacCook, however, says that 'these ants are not always so jealous of

territorial encroachment, or at least must have different standards of

rights.' For he observed many cases of nests situated within twenty, and

even ten feet of one another, without a battle ever occurring between

members of the two communities. Therefore, without questioning the

accuracy of Lincecum's observations--which, indeed, present no scope for

inaccuracy--he adds, 'That neighbouring ants, like neighbouring nations

of civilised men, will fall out and wage war Lincecum's examples show.

Perhaps we should be quite as unsuccessful in case of these ants as of

our human congeners, should we seek a sufficient reason for these wars,

or satisfactory cause for these differences in dealing with neighbours

which appear from the comparison of Lincecum's observations with mine.'

In connection with the wars of these ants, the following quotations may

also be made from the same author:--

The erratic ants do not appear to be held as common

enemies by the agriculturals, and they are even

permitted to establish their formicaries within the

limits of the open disk. Sometimes, however, the

diminutive hillocks which mark the entrance to an

erratic ant-nest multiply beyond the limit of the

agriculturals' forbearance. But they do not declare

war, nor resort to any personal violence.

Nevertheless, they get rid of them, oddly enough, by a

regular system of vexatious obstructions. They

suddenly conclude that there is urgent demand for

improving their public domain. Forthwith they sally

forth in large numbers, fall eagerly to work gathering

the little black balls which are thrown up by the

earth-worms in great quantities everywhere in the

prairie soil, which they bring and heap upon the paved

disk until all the erratic ant-nests are covered! The

entire pavement is thus raised an inch or so, and

pains are taken to deposit more balls upon and around

the domiciles of their tiny neighbours than elsewhere.

The erratics struggle vigorously against this Pompeian

treatment; they bore through the avalanche of balls,

only to find barriers laid in their way. The

obstructions at length become so serious that it is

impossible to keep the galleries open. The dwarfs

cease to contend against destiny, and, gathering

together their household stores, quietly evacuate the

premises of the inhospitable giants. It is the triumph

of the policy of obstruction, a bloodless but

effectual opposition.

Lastly, MacCook records the history of an interesting engagement which

he witnessed between two nests of _Tetramorium cæspitum_. It took place

between Broad Street and Penn Square in Philadelphia, and lasted for

nearly three weeks. Although all the combatants belonged to the same

species, however great the confusion of the fight, friends were always

distinguished from foes--apparently by contact of antennæ.

_Habit of keeping Domestic Pets._--Many species of ants display the

curious habit of keeping in their nests sundry kinds of other insects,

which, so far as observation extends, are of no benefit to the ants, and

which therefore have been regarded by observers as mere domestic pets.

These 'pets' are for the most part species which occur nowhere else

except in ants' nests, and each species of 'pet' is peculiar to certain

species of ants. Thus Moggridge found 'a large number of a minute

shining brown beetle moving about among the seeds' in the nests of the

harvesting ant of the south of Europe, 'belonging to the scarce and very

restricted genus _Colnocera_, called by Kraatz _C. attæ_, on account of

its inhabiting the nests of ants belonging to the genus _Atta_.' He also

observed inhabiting the same nests a minute cricket 'scarcely larger

than a grain of wheat' (_Gryllus myrmecophilus_), which had been

previously observed by Paolo Savi in the nests of several species of

ants in Tuscany, where it lived on the best terms with its hosts,

playing round the nests in warm weather, and retiring into them in

stormy weather, while allowing the ants to carry it from place to place

during migrations. Again, Mr. Bates observes that 'some of the most

anomalous forms of coleopterous insects are those which live solely in

the nests of ants.' Sir John Lubbock also, and other observers whom we

need not wait to cite, mention similar facts. The Rev. Mr. White says

that altogether 40 distinct species of Coleoptera, most of which he has

in his own collection, are known to inhabit the nests of various species

of ants, and to occur nowhere else.

As in all these cases the ants live on amicable terms with their guests,

and in some cases even bestow labour upon them (as in carrying them from

one nest to another during migration), it is evident that these insects

are not only tolerated, but fostered by the ants. Moreover, as it seems

absurd to credit ants with any mere fancy or caprice such as that of

keeping pets, we can only conclude that these insects, like the aphides,

are of some use to their hosts, although we are not yet in a position to

surmise what this use can be.

_Habits of Sleep and Cleanliness._--It is probable that all species of

ants enjoy periods of true sleep alternating with those of activity; but

actual observations on this subject have only been made on two or three

species. The following is MacCook's account of these habits in the

harvesting ant of Texas:--

The observation upon the ants now before me began at 8

o'clock; at 11 P.M. the cluster had nearly dissolved,

only a few being asleep. To illustrate the soundness

of this sleep I take the quill pen with which I write,

and apply the feather end of it to an ant who is

sleeping upon the soil. She has chosen a little oval

depression in the surface, and lies with abdomen upon

the raised edge, and face toward the lamp. Her legs

are drawn up close to the body. She is perfectly

still. I gently draw the feather tip along the body,

stroking 'with the fur,' if I may so say. There is no

motion. Again and again this action is repeated, the

stroke gradually being made heavier, although always

quite gentle. Still there is no change. The strokes

are now directed upon the head, with the same result.

Now the tip is applied to the neck, the point at which

the head is united to the pro-thorax, with a waving

motion intended to produce a sensation of tickling.

The ant remains motionless. After continuing these

experiments for several minutes, I arouse the sleeper

by a sharp touch of the quill. She stretches out her

head, then her legs, which she also shakes, steps

nearer to the light, and begins to cleanse herself in

the manner already described. This act invariably

follows the waking of ants from sleep. The above

description applies to the general habit of somnolence

as observed upon the two named species of harvesting

ants for nearly four months. I have often applied the

quill, and even the point of a lead pencil, to the

sleeping Floridians without breaking their slumber.

There are some other details which have not appeared

in the behaviour of the individual just put under

observation.

Thus, I have several times seen the ants (_Crudelis_)

_yawning_ after awaking. I use this word for lack of

one which more accurately expresses the behaviour. The

action is very like that of the human animal; the

mandibles are thrown open with the peculiar muscular

strain which is familiar to all readers; the tongue

also is sometimes thrust out, and the limbs stretched

with the appearance, at least, of that tension which

accompanies the yawn in the genus _homo_. During sleep

the antennæ have a gentle, quivering, apparently

involuntary motion, which seemed to me, at times, to

have the regularity of breathing. I also often noted

an occasional regular lifting up and setting down of

the fore-feet, one leg after another, with almost a

rhythmic motion.

The length of time during which sleep is prolonged

appears to vary according to circumstances and,

perhaps, organism. The large head-soldiers of the

Floridian harvesters appear to have a more sluggish

nature than the smaller workers. Their sleep is longer

and heavier. The former fact the watch readily

determined. The latter appeared from the greater

stolidity of the creatures under disturbance. While

the ants of one group are taking sleep others may be

busy at work, and these stalk among and over the

sleepers, jostling them quite vigorously at times.

Again, new members occasionally join the group, and,

in their desire to get close up to the heat and light,

crowd their drowsy comrades aside. I have seen ants

who had been at work in the galleries drop their

pellets, push thus into the cluster, and presently be

apparently sound asleep. This rough treatment is

invariably received with perfect good humour, as are

like jostlings when the ants are awake. I have never

seen the slightest display of anger or attempt to

resent disturbance even under these circumstances, so

peculiarly calculated to excite the utmost irritation

in men. But of course some of the sleepers are

aroused. They change position a little, or give

themselves a brief combing, and then resume their nap,

unless, indeed, they are satisfied. In watching these

movements it was quite evident that the Florida

soldiers were far less easily disturbed than their

smaller fellows. They slept on stolidly while all the

others were in agitation around them. Moreover, their

very appearance, particularly when awaking out of

sleep, indicated the greater sluggishness of their

temperament in this respect.

The ordinary duration of sleep MacCook takes to be about three hours.

Ants, like many other insects, are in the habit of cleaning themselves,

being, like them, provided by nature with combs and brushes, &c., for

the purpose. But, unlike other insects, several species of ants are also

in the habit of assisting each other in the performance of their toilet.

The author last quoted gives the following account of this process in

the genus _Atta_:--

We take a couple; the cleanser has begun at the face,

which is licked thoroughly, even the mandibles being

cared for, they being held apart for convenient

manipulation. From the face the cleanser passes to the

thorax, thence to the haunch, and so along the first

leg, along the second and third in the same manner,

around to the abdomen, and thence up the other side of

the ant to the head. A third ant approaches and joins

in the friendly task, but soon abandons the field to

the original cleanser. The attitude of the cleansed

all this while is one of intense satisfaction, quite

resembling that of a family dog when one is scratching

the back of his neck. The insect stretches out her

limbs, and, as her friend takes them successively into

hand, yields them limp and supple to her manipulation;

she rolls gently over upon her side, even quite over

upon her back, and with all her limbs relaxed presents

a perfect picture of muscular surrender and ease. The

pleasure which the creatures take in being thus

'combed' and 'sponged' is really enjoyable to the

observer. I have seen an ant kneel down before another

and thrust forward the head, drooping, quite under the

face, and lie there motionless, thus expressing, as

plainly as sign-language could, her desire to be

cleansed. I at once understood the gesture, and so did

the supplicated ant, for she at once went to work. If

analogies in nature-studies were not so apt to be

misleading, one might venture to suggest that our

insect friends are thus in possession of a modified

sort of Emmetonian Turkish bath.

The acrobatic skill of these ants, which has often

furnished me amusement, and which I shall yet further

illustrate, was fully shown one morning in these

offices of ablution. The formicary was taken from the

study, where the air had become chilled, and placed in

an adjoining chamber upon the hearth, before an

open-grate fire. The genial warmth was soon diffused

throughout the nest, and aroused its occupants to

unusual activity. A tuft of grass in the centre of the

box was presently covered with them. They climbed to

the very top of the spires, turned round and round,

hanging by their paws, not unlike gymnasts performing

upon a turning-bar. They hung or clung in various

positions, grasping the grass blade with the third and

fourth pairs of legs, which were spread out at length,

cleansing their heads with the fore-legs or bending

underneath to comb and lick the abdomen. Among these

ants were several pairs, in one case a triplet,

engaged in the cleansing operation just described. The

cleanser clung to the grass, having a fore-leg on one

side and a hind leg on the other side of the stem,

stretched out at full length, while the cleansed hung

in a like position below, and reached over and up,

submitting herself to the pleasant process. As the

progress of the act required a change of posture on

the part of both insects, it was made with the utmost

agility.

Similarly, Bates thus describes the cleansing process in another genus

of ants (_Ecitons_):--

Here and there an ant was seen stretching forth first

one leg and then another, to be brushed and washed by

one or more of its comrades, who performed the task by

passing the limb between the jaws and tongue,

finishing by giving the antennæ a friendly wipe.

_Habits of Play and Leisure._--The life of ants is not all work, or, at

least, is not so in all species; for in some species, at any rate,

periods of recreation are habitually indulged in.

Büchner('Geistesleben der Thiere,' p. 163) gives the following abstract

of Huber's celebrated observations in this connection:--

It was of the _pratensis_ that Huber wrote the

observations touching its gymnastic sports which

became so famous. He saw these ants on a fine day

assembled on the surface of their nest, and behaving

in a way that he could only explain as simulating

festival sports or other games. They raised themselves

on their hind legs, embraced each other with their

fore-legs, seized each other by the antennæ, feet, or

mandibles, and wrestled--but all in friendliest

fashion. They then let go, ran after each other, and

played hide-and-seek. When one was victorious, it

seized all the others in the ring, and tumbled them

over like ninepins.

This account of Huber's found its way into many

popular books, but in spite of its clearness won

little credence from the reading public. 'I found it

hard to believe Huber's observation,' writes Forel,

'in spite of its exactness, until I myself had seen

the same.' A colony of the _pratensis_ several times

gave him the opportunity when he approached it

carefully. The players caught each other by the feet

or jaws, rolled over each other on the ground like

boys playing, pulled each other inside the entrances

of their nest, only to come out again, and so on. All

this was done without bad temper, or any spurting of

poison, and it was clear that all the rivalry was

friendly. The least breath from the side of the

observer was enough to put an end to the games. 'I

understand,' continues Forel, 'that the affair must

seem marvellous to those who have not seen it,

especially when we remember that sexual attraction can

here play no part.'

MacCook also gives an account of habits of play as indulged in among

ants of the other Hemisphere:--

At one formicary half a dozen or more young queens

were out at the same time. They would climb up a large

pebble near the gate, face the wind, and assume a

rampant posture. Several having ascended the stone at

one time, there ensued a little playful

passage-at-arms as to position. They nipped each other

gently with the mandibles, and chased one another from

favourite spots. They, however, never nipped the

workers. These latter evidently kept a watch upon the

sportive princesses, occasionally saluted them with

their antennæ in the usual way, or touched them at the

abdomen, but apparently allowed them full liberty of

action.

As to leisure, Bates writes:--

The life of these Ecitons is not all work, for I

frequently saw them very leisurely employed in a way

that looked like recreation. When this happened the

place was always a sunny nook in the forest. The main

column of the army and the branch columns, at these

times, were in their ordinary relative positions; but

instead of pressing forward eagerly and plundering

right and left, they seemed to have been all smitten

with a sudden fit of laziness. Some were walking

sternly about, others were brushing their antennæ with

their fore-feet; but the drollest sight was their

cleaning each other. [Here follows the above-quoted

passage.] The actions of these ants looked like simple

indulgence in idle amusement. . . . It is probable

that these hours of relaxation and cleaning may be

indispensable to the effective performance of their

harder burdens; but whilst looking at them, the

conclusion that the ants were engaged merely in play

was irresistible.[31]

_Funereal Habits._--In another connection it has already been stated

that Sir John Lubbock found his ants to be very careful in disposing of

the dead bodies of their comrades. This habit seems to be pretty general

among many species of ants, and is no doubt due to sanitary

requirements, thus becoming developed as a beneficial instinct by

natural selection. The funereal habits of the agricultural ant are thus

related by MacCook:[32]--

There is nothing which is apt to awaken deeper

interest in the life-history of ants than what may

properly be called their funereal habits. All species

whose manners I have closely observed are quite alike

in their mode of caring for their own dead, and for

the dry carcasses of aliens. The former they appear to

treat with some degree of reverence, at least to the

extent of giving them a sort of sepulture without

feeding upon them. The latter, after having exhausted

the juices of the body, they usually deposit together

in some spot removed from the nest. I did not see any

of the 'cemeteries' of the agricultural ant upon the

field, nor, indeed, observe any of their behaviour

towards the dead, but my artificial nests gave me some

insight of this. In the first colony had been placed

eight agriculturals of another nest, which were

literally cut to pieces. Very soon after the ants were

comfortably established in their new home, a number of

them laid hold upon these _disjecta membra_, and began

carrying them back and forth around the formicarium.

The next day this continued, and several of their own

number who had died were being treated in like

manner. Back and forth, up and down, into every corner

of the box the bearers wandered, the very embodiment

of restlessness. For four days this conduct continued

without any intermission. No sooner would a body or

fragment thereof be dropped by one bearer than another

would take it up and begin the restless circuit. The

difficulty, I easily understood, was that there was no

point to be found far enough removed from the

living-rooms of the insects in which to inter these

dead. Their desire to have their dead buried out of

their sight was strong enough to keep them on this

ceaseless round, apparently under the continuous

influence of the hope that something might turn up to

give them a more satisfactory burial-ground. It does

not appear greatly to the credit of their wisdom that

they were so long discovering that they were limited

to a space beyond their power to enlarge. When,

however, this fact was finally recognised they gave

their habit its utmost bent, and began to deposit the

carcasses in the extreme corner of the flat, as

distant as possible from the galleries on the terrace

above. Here a little hollow was made in the earth,

quite up against the glass, wherein a number of bodies

were laid. Portions of bodies were thrust into the

chinks formed in the dry sod. This flat became the

permanent charnel-house of the colony, and here, in

corners, crevices, and holes, for the most part out of

sight, but not always so, the dead were deposited. But

the living never seemed quite reconciled to their

presence. Occasionally, restless resurrectionists

would disentomb the dead, shift them to another spot,

or start them once more upon their unquiet wanderings.

Even after the establishment of this cemetery, the

creatures did not seem able to lay away their newly

deceased comrades--for there were occasional deaths in

the formicary--without first indulging in this

funereal promenade.

In the formicaries established in glass jars, both of

_barbatus_ and _crudelis_, the same behaviour

appeared. So great was the desire to get the dead

outside the nest, that the bearers would climb up the

smooth surface of the glass to the very top of the

jar, laboriously carrying with them a dead ant. This

was severe work, which was rarely undertaken except

under the influence of this funereal enthusiasm. The

jar was very smooth and quite high. Falls were

frequent, but patiently the little 'undertaker' would

follow the impulse of her instinct, and try and try

again. Finally, as in the large box, the fact of a

necessity seemed to dawn upon the ants, and a portion

of the surface opposite from the entrance to the

galleries, and close up against the glass, was used

as burial-ground and sort of kitchen-midden, where all

the refuse of the nest was deposited. Mrs. Treat has

informed me that her artificial nests of _crudelis_

behaved in precisely the same way.

An interesting fact in the funereal habits of _Formica

sanguinea_ was related to me by this lady. A visit was

paid to a large colony of these slave-makers, which is

established on the grounds adjoining her residence at

Vineland, New Jersey. I noticed that a number of

carcasses of one of the slave species, _Formica

fusca_, were deposited together quite near the gates

of the nest. These were probably chiefly the dry

bodies of ants brought in from recent raids. It was

noticed that the dead ants were all of one species,

and thereupon Mrs. Treat informed me that the red

slave-makers never deposited their dead with those of

their black servitors, but always laid them by

themselves, not in groups, but separately, and were

careful to take them a considerable distance from the

nest. One can hardly resist pointing here another

likeness between the customs of these social

hymenopters and those of human beings, certain of whom

carry their distinctions of race, condition, or

religious caste, even to the gates of the cemetery in

which the poor body moulders into its mother dust!

It will be observed that none of these accounts furnish evidence of ants

burying their dead, as Pliny asserts to have been the case with ants in

the south of Europe. In the Proceedings of the Linnæan Society, however

(1861), there is a very definite account of such a practice as obtaining

among the ants of Sydney; and although it is from the pen of an observer

not well known, the observation seems to have been one about which there

could scarcely have been a mistake. The observer was Mrs. Hutton, and

this is her account. Having killed a number of 'soldier ants,' and

returning half an hour afterwards to the place where the dead bodies

were lying, she says:

I saw a large number of ants surrounding the dead

ones. I determined to watch their proceedings closely.

I followed four or five that started off from the rest

towards a hillock a short distance off, in which was

an ants' nest. This they entered, and in about five

minutes they reappeared, followed by others. All fell

into rank, walking regularly and slowly two by two,

until they arrived at the spot where lay the dead

bodies of the soldier ante. In a few minutes two of

the ants advanced and took up the dead body of one of

their comrades; then two others, and so on, until all

were ready to march. First walked two ants bearing a

body, then two without a burden; then two others with

another dead ant, and so on, until the line was

extended to about forty pairs, and the procession now

moved slowly onwards, followed by an irregular body of

about two hundred ants. Occasionally the two laden

ants stopped, and laying down the dead ant, it was

taken up by the two walking unburdened behind them,

and thus, by occasionally relieving each other, they

arrived at a sandy spot near the sea. The body of ants

now commenced digging with their jaws a number of

holes in the ground, into each of which a dead ant was

laid, where they now laboured on until they had filled

up the ants' graves. This did not quite finish the

remarkable circumstances attending this funeral of the

ants. Some six or seven of the ants had attempted to

run off without performing their share of the task of

digging; these were caught and brought back, when they

were at once attacked by the body of ants and killed

upon the spot. A single grave was quickly dug, and

they were all dropped into it.

The Rev. W. Farren White also, in his papers on ants published in the

'Leisure Hour' (1880), after alluding to the above case, corroborates it

by some interesting observations of his own. He says:--

Several of the little sextons I observed with dead in

their mandibles, and one in the act of burying a

corpse. . . . I should mention that the dead are not

interred without considerable difficulty, in

consequence of the sides of the trays being almost

perpendicular. The work of the sextons continued until

no dead bodies remained upon the surface of the nest,

but all were interred in the extramural cemeteries.

Afterwards I removed the trays, and turned the

contents of the formicarium upside down, and then I

placed six trays on the surface of the earth, two of

which I filled with sugar for food. All six were used

freely as cemeteries, being crowded with the corpses

of the little people and their young, the larvæ which

had perished in the disruption of their home.

I have noticed in one of my formicaria a subterranean

cemetery, where I have seen some ants burying their

dead by placing earth above them. One ant was

evidently much affected, and tried to exhume the

bodies, but the united exertions of the yellow sextons

were more than sufficient to neutralise the effort of

the disconsolate mourner. The cemetery was now

converted into a large vault, the chamber where the

dead were placed, together with the passage which led

to it, being completely covered in.

_Habits Peculiar to Certain Species._

_Leaf-cutting Ants of the Amazon_ ([OE]codoma cephalotes).--The mode of

working practised by these ants is thus described by Mr. Bates:--

They mount a tree in multitudes. . . . Each one places

itself on the surface of a leaf, and cuts with its

sharp scissor-like jaws a nearly semicircular incision

on the upper side; it then takes the edge between its

jaws, and by a sharp jerk detaches the piece.

Sometimes they let the leaf drop to the ground, where

a little heap accumulates, until carried off by

another relay of workers; but generally each marches

off with the piece it has operated on, and as all take

the same road to the colony, the path they follow

becomes in a short time smooth and bare, looking like

the impression of a cart-wheel through the herbage.

Each ant carries its semicircular piece of leaf upright over its head,

so that the home-returning train is rendered very conspicuous. Nearer

observation shows that this home-returning or ladened train of workers

keeps to one side of the road, while the outgoing or empty-handed train

keeps to the other side; so that on every road there is a double train

of ants going in opposite directions. When the leaves arrive at the nest

they are received by a smaller kind of workers, whose duty it is to cut

up the pieces of leaf into still smaller fragments, whereby the leaves

seem to be better fitted for the purpose to which, as we shall presently

see, they are put. These smaller workers never take any part in the

outdoor labours; but they occasionally leave the nest, apparently for

the sole purpose of obtaining air and exercise, for when they leave the

nest they merely run about doing nothing, and frequently, as if in mere

sport, mount some of the semicircular pieces of leaf which the carrier

ants are taking to the nest, and so get a ride home.

From his continued observation of these ants, Bates concludes--and his

opinion has been corroborated by that both of Belt and Müller--that the

object of all this labour is highly interesting and remarkable. The

leaves when gathered do not themselves appear to be of any service to

the ants as food; but when cut into small fragments and stored away in

the nests, they become suited as a nidus for the growth of a minute kind

of fungus on which the ants feed. We may therefore call these insects

the 'gardening ants,' inasmuch as all their labour is given to the

rearing of nutritious vegetables on artificially prepared soil. They are

not particular as to the material which they collect and store up for

soil, provided that it is a material on which the fungus will grow. Thus

they are very partial to the inside white rind of oranges, and will

carry off the flowers of certain shrubs while leaving the leaves

untouched. But, to quote again from Bates,--

They are very particular about the ventilation of

their underground chambers, and have numerous holes

leading up to the surface from them. These they open

out or close up, apparently to keep up a regular

degree of temperature below. The great care they take

that the pieces of leaves they carry into the nest

should be neither too dry nor too damp, is also

consistent with the idea that the object is the growth

of a fungus that requires particular conditions of

temperature and moisture to ensure its vigorous

growth. If a sudden shower should come on, the ants do

not carry the wet pieces into the burrows, but throw

them down near the entrances. Should the weather clear

up again, these pieces are picked up when nearly

dried, and taken inside: should the rain, however,

continue, they get sodden down into the ground, and

are left there. On the contrary, in dry and hot

weather, when the leaves would get dried up before

they could be conveyed to the nest, the ants, when in

exposed situations, do not go out at all during the

hot hours, but bring in their leafy burdens in the

cool of the day and during the night. As soon as the

pieces of leaves are carried in they must be cut up by

the small class of workers into little pieces. Some of

the ants make mistakes, and carry in unsuitable

leaves. Thus grass is always rejected by them, but I

have seen some ants, perhaps young ones, carrying

leaves of grass; but after a while these pieces are

always brought out again and thrown away. I can

imagine a young ant getting a severe ear-wigging from

one of the major-domos for its stupidity.

When a nest is disturbed and the masses of ant-food

spread about, the ants are in great concern to carry

every morsel of it under shelter again; and sometimes,

when I had dug into a nest, I found the next day all

the earth thrown out filled with little pits, that the

ants had dug into it to get out the covered-up food.

When they migrate from one part to another, they also

carry with them all the ant-food from their old

habitations.

In Büchner's 'Geistesleben der Thiere' there is published an interesting

description of the habits of these ants, which was communicated to the

author by Dr. Fr. Ellendorf of Wiedenbrück, who has lived many years in

Central America. Dr. Ellendorf says that--

It would be quite impossible for them to creep even

through short grass with loads on their heads for

miles. They therefore bite off the grass close to the

ground for a breadth of about five inches, and throw

it on one side. Thus a road is constructed, which is

finally made quite smooth and even by the continual

passing to and fro of millions upon millions night and

day. . . . If the road is looked down upon from a height

with these millions thickly pressed together, and all

moving along with their green bannerets over their

heads, it looks as though a giant green snake were

gliding slowly along the ground; and this picture is

all the more striking in that all these bannerets are

swaying backwards and forwards.[33]

This observer made the experiment of interrupting the advance of a

column of these ants, with the interesting result which he describes:--

I wished to see how they would manage if I put an

obstacle in their way. Thick high grass stood on

either side of their narrow road, so that they could

not pass through it with the load on their heads. I

placed a dry branch, nearly a foot in diameter,

obliquely across their path, and pressed it down so

tightly on the ground that they could not creep

underneath. The first comers crawled beneath the

branch as far as they could, and then tried to climb

over, but failed owing to the weight on their heads.

Meanwhile the unloaded ants from the other side came

on, and when these succeeded in climbing over the

bough there was such a crush that the unladen ants had

to clamber over the laden, and the result was a

terrible muddle. I now walked along the train, and

found that all the ants with their bannerets on their

heads were standing still, thickly pressed together,

awaiting the word of command from the front. When I

turned back to the obstacle, I saw with astonishment

that the loads had been laid aside by more than a

foot's length of the column, one imitating the other.

And now work began on both sides of the branch, and in

about half an hour a tunnel was made beneath it. Each

ant then took up its burden again, and the march was

resumed in the most perfect order.

A migration of these ants is thus described by the same observer:--

The road led towards a cocoa plantation, and here I

soon discovered the building which I afterwards

visited daily. As I again went thither one day I was

met, at a considerable distance from the nest, by a

closely pressed column coming thence, and all the ants

laden with leaves, beetles, pupæ, butterflies, &c.;

the nearer I came to the nest, the greater was the

activity. It was soon plain to me that the ants were

in the act of leaving their dwelling, and I walked

along the train to discover the new abode. They had

gone for some distance along the old road, and had

then made a new one through the grass to a cooler

place, lying rather higher. The grass on the new road

was all bitten off close to the ground, and thousands

were busy carrying the path on to the new building. At

the new home itself was an unusual stir of life. There

were all sorts of labourers--architects, builders,

carpenters, sappers, helpers. A number were busy

digging a hole in the ground, and they carried out

little pellets of earth and laid them together on end

to make a wall. Others drew along little twigs,

straws, and grass-stalks, and put them near the place

of building. I was anxious to know why they had

quitted their old home, and when the departure was

complete, I dug it up with a spade. At a depth of

about a foot and a half I found several tunnels of a

large marmot species, the terror of cocoa planters,

because in making their passages they gnaw off the

thickest roots of the cocoa plants. The interior of

the ant-hill had apparently fallen in through these

mines. Unfortunately I was unable to follow further

the progress of the new building, for I was obliged to

leave the next day for San Juan del Sur. When I

returned at the end of a week the building was

finished, and the whole colony was again busy with the

leaves of the coffee plants.

_Harvesting Ants_ (Atta).--The ants which, so far as at present known,

practise the peculiar and distinctive habits to be described under this

division belong for the most part to one genus, _Atta_, which, however,

comprises a number of species distributed in localised areas over all

the four quarters of the globe. Hitherto nineteen species have been

detected as having the habits in question. These consist of gathering

nutritious seeds of grasses during summer, and storing them in granaries

for winter consumption. We owe our present knowledge concerning these

insects to Mr. Moggridge,[34] who studied them in the south of Europe,

Dr. Lincecum,[35] and Mr. MacCook,[36] who studied them in Texas, and

Colonel Sykes[37] and Dr. Jerdon,[38] who made some observations upon them

in India. They also occur scattered over a great part of Europe and in

Palestine, where they were clearly known to Solomon and other classical

writers of antiquity,[39] whose claim to accurate observation, although

long disputed (owing to the authority of Huber), has now been amply

vindicated.

Mr. Moggridge, who was a careful and industrious observer, found the

following points of interest in the habits of the European harvesters.

From the nest in various directions there proceed outgoing trains, which

may be from twenty to thirty or more yards in length, and each consists

of a double row of ants, moving, like the leaf-cutting ants, in opposite

directions. Those in the outgoing row are empty-handed, while those in

the incoming row are laden. But here the burdens are grass seeds. The

roads terminate in the foraging ground, or ant-fields, and the insects

composing the columns there become dispersed by hundreds among the

seed-yielding grasses. The following is their method of collecting

seeds; I quote from Moggridge:--

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

to 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

(_Stellaria media_) and entire calyces, containing the

nutlets of calamint, 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 of the manner in which the

spikelets of corn are severed and thrown down 'to the

people below,' [Greek: tô dêmô tô katô].

The recognition of the principle of the division of labour which the

latter observation supplies, is further proved by the following

quotation from the same author. A dead grasshopper which was being

carried into their nest was--

Too large to pass through the door, so they tried to

dismember it. Failing in this, several ants drew the

wings and legs as far back as possible, while others

gnawed through the muscles where the strain was

greatest. They succeeded at last in thus pulling it

in.

The same thing is strikingly shown by the following quotation from

Lespès:--

If the road from the place where they are gathering

their harvest to the nest is very long, they make

regular depôts for their provisions under large

leaves, stones, or other suitable places, and let

certain workers have the duty of carrying them from

depôt to depôt.

Büchner (_loc. cit._ p. 101) also makes the following references to the

statements of previous observers:--

The subterranean workers of this remarkable genus are

very clever. The Rev. H. Clark reports from Rio de

Janeiro, that the _Sa-ubas_ have made a regular tunnel

under the bed of the river Parahyba, which is there as

broad as the Thames at London, in order to reach a

storehouse which is on the opposite bank. Bates tells

us that close to the Magoary rice-mills, near Para,

the ants bored through the dam of a large reservoir,

and the water escaped before the mischief could be

remedied. In the Para Botanical Gardens an

enterprising French gardener did everything he could

to drive the _Sa-ubas_ away. He lit fires at the chief

entrances of their nests, and blew sulphur vapour into

their galleries by means of bellows. But how

astonished was Bates when he saw the vapour come out

at no less a distance than seventy yards! Such an

extension have the subterranean passages of the

_Sa-ubas_.

The recognition of the principle of the division of labour, which is

shown by the above observations, is further corroborated by the

following quotation from Belt:--

Between the old burrows and the new one was a steep

slope. Instead of descending this with their burdens,

they cast them down on the top of the slope, whence

they rolled down to the bottom, where another relay of

labourers picked them up and carried them to the new

burrow. It was amusing to watch the ants hurrying out

with bundles of food, dropping them over the slope,

and rushing back immediately for more.

The same thing has been observed, as already stated, of the leaf-cutting

ants--those engaged in cutting frequently throwing down the fragments of

leaf which they cut to the carriers below. The prevalence of this habit

among various species of ants therefore renders credible the following

statements of Vincent Gredler of Botzen which are thus recorded in 'der

Zool. Gart.,' xv. p. 434:--

In Herr Gredler's monastery one of the monks had been

accustomed for some months to put food regularly on

his window-sill for ants coming up from the garden.

In consequence of Herr Gredler's communications he

took it into his head to put the bait for the ants,

pounded sugar, into an old inkstand, and hung this up

by a string to the cross-piece of his window, and left

it hanging freely. A few ants were in with the bait.

These soon found their road out over the string with

their grains of sugar, and so their way back to their

friends. Before long a procession was arranged on the

new road from the window-sill along the string to the

spot where the sugar was, and so things went on for

two days, nothing fresh occurring. But one day the

procession stopped at the old feeding-place on the

window-sill, and took the food thence, without going

up to the pendent sugar-jar. Closer observation

revealed that about a dozen of the rogues were in the

jar above, and were busily and unwearyingly carrying

the grains of sugar to the edge of the pot, and

throwing them over to their comrades down below.

Many other instances of the division of labour might be given besides

these, and those to be mentioned hereafter in other connections

throughout the course of the present chapter; but enough has been said

to show that the principle is unquestionably acted upon by sundry

species of ants.

That ants are liable to make mistakes, and, when they do, that they

profit by experience, is shown by the following experiment made by

Moggridge; and many other instances might be given were it desirable:--

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 strewed 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.

When the grain is thus taken into the nest, it is stored in regular

granaries, but not until it has been denuded of its 'husks' or 'chaff.'

The denuding process is carried on below ground, and the chaff is

brought up to the surface, where it is laid in heaps to be blown away by

the wind.

It is a remarkable thing, and one not yet understood, why the seed, when

thus stored in subterranean chambers just far enough below the surface

to favour germination, does not germinate. Moggridge says that out of

twenty-one nests and among many thousands of seeds that he examined, he

only found twenty-seven cases of incipient germination. Moreover, all

these cases occurred in months from November to February, while in the

nests opened in October, March, April, and May, no sprouted seeds were

discovered, though these are the months highly favourable to

germination. He is at a loss to suggest the treatment to which the ants

expose the seeds in order to prevent their sprouting. '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 he has proved that the vitality of the seeds is not impaired, for he

succeeded in raising crops of young plants from seeds removed from the

granaries.

He also says,--

By a fortunate chance I have been able to prove that

the seeds will germinate in an undisturbed granary

when the ants are prevented from obtaining access to

it: and this goes to show not only that the structure

and nature of the granary chamber is not sufficient of

itself to prevent germination, but also that the

presence of the ants is essential to secure the

dormant condition of the seeds.

I discovered in two places portions of distinct nests

of _Atta structor_ which had been isolated owing to

the destruction of the hollow wall behind which they

lay, and then the granaries well filled up and

literally choked with growing seeds, though the earth

in which they lay completely enclosed and concealed

them until by chance I laid them bare. In one case I

knew that the destruction of the wall had only taken

place ten days before, so that the seeds had sprouted

in the interval.

My experiments also tend to confirm this, and to

favour the belief that the non-germination of the

seeds is due to some direct influence voluntarily

exercised by the ants, and not merely to the

conditions found in the nest, or to acid vapours which

in certain cases are given off by the ants themselves.

These experiments consisted in confining a large number of harvesting

ants with their queen and larvæ in a glass test-tube partly filled with

damp soil and various seeds, the whole being closed with a cork in the

mouth of the test-tube. Under these circumstances the seeds all

sprouted, showing that mere confinement in an atmosphere of exhalations

from the ants did not prevent germination. Another series of

experiments, undertaken at the suggestion of Mr. Darwin, on the effects

of an atmosphere of formic acid, showed that although this vapour was

very injurious to the seeds, it did not prevent their incipient

germination. Therefore it yet remains to be ascertained why the seeds do

not germinate in the granaries of the ants.

But in whatever way the ants manage to prevent germination, it is

certain that they are aware of the importance in this connection of

keeping the seeds as dry as possible; for Moggridge repeatedly observed

that when the seeds which had been stored proved over-moist, the ants

again took them out and spread them in the sun to dry, to be again

brought into the nest after a sufficient exposure.

Lastly, he also repeatedly observed the most surprising and interesting

fact that when, as we have seen was occasionally the case, the seeds did

begin to germinate in the nests, the ants knew the most effective method

of preventing the germination from proceeding; for he found that in

these cases the ants gnawed off the tips of the radicles. This fact

deserves to be considered as one of the most remarkable among the many

remarkable facts of ant-psychology.

Passing on now to the harvesting or agricultural ants of Texas,

attention was first called to the habits of this insect by Mr. Buckley

in 1860,[40] and by Dr. Lincecum, who sent an account of his observations

to Mr. Darwin, by whom they were communicated to the Linnæan Society in

1861. Five years later a paper was published in the Proceedings of the

Academy of Natural Sciences of Philadelphia from the MS. of Dr.

Lincecum. Lastly, in 1877 Mr. MacCook went to Texas expressly to study

the habits of these insects, and he has recently embodied the results of

his observations in a book of three hundred pages.[41] These observations

are for the most part confirmatory of those of Lincecum, and for this as

well as for reasons to be deduced from the work itself, they deserve to

be accepted as trustworthy, notwithstanding that in some cases they are

provokingly incomplete. The following is an epitome of these

observations.

The ants clear away all the herbage above their nest in the form of a

perfect circle, or 'disk,' 15 or 20 feet in diameter, by carefully

felling every stalk of grass or weed that may be growing thereon. As the

nests are placed in thickly grown localities, the effect of these bald

or shaven disks is highly conspicuous and peculiar, exactly resembling

in miniature the clearings which the settlers make in the American

backwoods. The disk, however, is not merely cleared of herbage, but also

carefully levelled, all inequalities of the surface being reduced by

building pellets of soil into the hollows to an extent sufficient to

make a uniformly flat surface. The action of rain and the constant

motion of multitudes of ants cause this flat surface to become hard and

smooth. In the centre of the disk is the gateway of the nest. This may

be either a simple hole or a hollow cone.

From the disk in various directions there radiate ant-roads or avenues,

which are cleared and smoothed like the disk itself, and which course

through the thick surrounding grass, branching and narrowing as they go

till they eventually taper away. These roads are usually three or four

in number before they begin to branch, but may be as many as seven.

They are usually two to three inches wide at their origin, but in large

nests may be as much as five. MacCook found no road longer than sixty

feet, but Lincecum describes one of three hundred feet. Along these hard

and level roads there is always passing, during the daytime of the

harvesting season, a constant stream of ants--those going from the nest

being empty-handed, and those returning to it being laden with seeds. Of

course the incoming ants, converging from all quarters upon the road,

and therefore increasing in numbers as they approach the nest, require

greater space for free locomotion; while the outgoing ants, diverging as

they get further from home, also require greater proportional space the

less their distance from the nest: hence the gradual swelling in the

width of the roads as they approach the nests.

The manner of collecting the seeds in the jungle surrounding the roads

is thus described by MacCook:--

At last a satisfactory seed is found. It is simply

lifted from the ground, or, as often happens, has to

be pulled out of the soil into which it has been

tightly pressed by the rain or by passing feet. Now

follows a movement which at first I thought to be a

testing of the seed, and which, indeed, may be

partially that; but finally I concluded that it was

the adjusting of the burden for safe and convenient

carriage. The ant pulls at the seed-husk with its

mandibles, turning and pinching or 'feeling' it on all

sides. If this does not satisfy, and commonly it does

not, the body is raised by stiffening out the legs,

the abdomen is curved underneath, and the apex applied

to the seed. I suppose this to be simply a mechanical

action for the better adjusting of the load. Now the

worker starts homeward. It has not lost itself in the

mazes of the grass forest. It turns directly towards

the road with an unerring judgment. There are many

obstacles to overcome. Pebbles, pellets of earth, bits

of wood, obtruding rootlets, or bent-down spears of

grass block up or hinder the way. These were scarcely

noticed when the ant was empty-handed. But they are

troublesome barriers now that she is burdened with a

seed quite as thick, twice as wide, and half as long

as herself. It is most interesting to see the skill,

strength, and rapidity with which the little harvester

swings her treasure over or around, or pushes it

beneath these obstacles. Now the seed has caught

against the herbage as the porter dodges under a too

narrow opening. She backs out and tries another

passage. Now the sharp points of the husk are

entangled in the grass. She jerks or pulls the burden

loose, and hurries on. The road is reached, and

progress is comparatively easy. Holding the grain in

her mandibles well above the surface, she breaks into

what I may describe with sufficient accuracy as 'a

trot,' and with little further interruption reaches

the disk and disappears within the gate. There are

variations from this behaviour, more or less marked,

according to the nature of the grounds, the seeds, and

(I suppose) the individuality of the harvesters; but

the mode of ingathering the crop is substantially as

above. Each ant operated independently. Once only did

I see anything like an effort to extend sympathy and

aid. A worker minor seeming to have difficulty in

testing or adjusting a large seed of buffalo-grass,

was assisted (apparently) by one worker major, and

then by another, after which she went on her way.

But these ants do not confine their harvesting operations to gathering

fallen seeds; they will, like the ants of Europe, also cut seeds from

the stalk.

In order to test the disposition of _crudelis_ to

garner the seeds from the stem, bunches of millet were

obtained from the North, and stalks eighteen inches

high, crowned by the boll of close-set seeds, were

stuck in the mound of an active formicary. The ants

mounted the stems and set to work vigorously to secure

the seeds, clusters of twenty or more being engaged at

once upon one head. The seeds were carried off and

stored within the nest. This experiment proved pretty

conclusively that in the seeding season _crudelis_

does not wait for the seeds to drop, but harvests them

from the plant.

The 'granaries' into which the seeds are brought are kept distinct from

the 'nurseries' for the pupæ. Their walls, floor, and roof are so hard

and smooth, that MacCook thinks the insects must practise upon them

'some rude mason's craft.'

He traced these granaries to a depth of four feet below the surface of

the ground, and believes, from the statements of a native peasant, that

they, or at least the formicaries, extend to a depth of fifteen feet.

As regards the care that the ants take of the gathered grain, Lincecum

describes the same habit as Moggridge and Sykes describe--viz., the

sunning of wet seeds to dry. MacCook, however, neglected to make any

experiments on this subject. Neither has he been able to throw any light

upon the question as to why the stored seeds do not germinate, and is

doubtful whether the habit of gnawing the radicle of sprouting seeds,

which prevails in the European species, is likewise practised by the

American. On two other points of importance MacCook's observations are

also incomplete. One of these has reference to an alleged statement,

which he is disposed to believe, that when some ants in a community have

been killed by poison, the survivors avoid the poison: he, however, made

no experiments to test this statement.

The other main point on which his observations are defective has

reference to a remarkable statement made by Lincecum in the most

emphatic terms. This statement is that upon the surface of their disk

the ants sow the seeds of a certain plant, called ant-rice, for the

purpose of subsequently reaping a harvest of the grain. There is no

doubt that the ant-disks do very often support this peculiar kind of

grass, and that the ants are particularly fond of its seed; but whether

the plant is actually sown in these situations by the insects, or grows

there on account of these situations being more open than the general

surface of the ground--this question MacCook has failed to answer, or

even to further. We are, therefore, still left with Dr. Lincecum's

emphatic assurance that he has witnessed the fact. His account is that

the seed of the ant-rice, which is a biennial plant, is sown in time for

the autumnal rains to bring up. At the beginning of November a green row

or ring of ant-rice, about four inches wide, is seen springing up round

the circumference of the disk. In the vicinity of this circular ring the

ants do not permit a single spire of any other grass or weed to remain a

day, but leave the aristida, or ant-rice, untouched until it ripens,

which occurs in June of the next year. After the maturing and harvesting

of the seed, the dry stubble is cut away and removed from the pavement

or disk, which is thus left unencumbered until the ensuing autumn, when

the same species of grass again appears as before, and so on. Lincecum

says he has seen the process go on year after year on the same

ant-farms, and adds,--