not himself witness the process of sowing, although he is not disposed to doubt the statements of his predecessor upon the subject. These statements, as already observed, are most emphatic and preciseLincecum saying, in italics, that he knows and is certain about the fact; but until corroborated it is safest to regard the fact as not yet fully established.

Honey-making Ants.-These ants are found in Texas and New Mexico. Their remarkable habits have been observed by Captain Fleeson, who communicated his observations to Mr. Darwin.

The community consists of three distinct kinds of ants, which appear to belong to two distinct genera. These are:

I. Yellow workers; nurses and feeders of II.

II. Yellow honey-makers; sole function to secrete a kind of honey in their large globose abdomens, on which the other ants are supposed to feed. They never quit the nest, and are fed and tended by I.

III. Black workers; guards and purveyors, which surround the nest as sentinels, and also forage for the food required for I. They are much larger and stronger than either I. or II., and are provided with very formidable mandibles.

The nest is in the form of an absolutely perfect square, of which each side measures from four to five feet, and the surface of which is kept quite unbroken save at two points, at each of which there is a very minute hole or entrance. One of these minute holes occurs near the west side of the square, and the other near the south-east corner; for it must be remarked that the square is always built with precise reference to the points of the compass, in such a way that one side faces due north, and consequently the others due south, east, and west. These boundaries are rendered very conspicuous by the guard of black workers or soldiers (III.), which continuously parade round three of the sides in a close double line of defence, moving in opposite directions. This sentry-path occupies the north, east, and west boundaries, the south side of the square being left open; but if an enemy approaches on this, or any other side, a number of the guards leave their stations and sally forth to face the foe, raising themselves on their hind legs on meeting the enemy, and moving their large mandibles in defiance. After tearing the enemy to pieces the guards return to their places in the line of defence, their object in destroying any insect or other small intruders being defence of the encampment, and not the obtaining of food.

The southern side of the square encampment, or rather fortress, is left open as just described in order to admit of a free entry of supplies. While some of the black workers are on duty as guard, another and larger division are engaged on duty as purveyors. These enter and leave the quadrangle by its south-west corner in a double line (one laden and the other not), which follows exactly the diagonal of the

square to its central point, where all the booty, consisting of flowers and aromatic leaves, is deposited in a heap. Passing from this central heap to the entrance at the south-east corner of the quadrangle, and therefore occupying the other semi-diagonal of the square, there is another double line of workers constantly engaged in carrying the booty from the central deposit into the store-houses below ground. These workers are exclusively composed of Class II., whose whole life is therefore spent in running backwards and forwards upon this semi-diagonal of the square, carrying in food and feeding Class I. No black ant is ever seen on the eastern diagonal, and no yellow ant is ever seen on the western; but each keeps to his own separate station, and here works with a steadfastness and apparent adherence to discipline which are not less remarkable than those exhibited by the sentries. The western hole before mentioned seems to be intended only as a ventilating shaft; it is never used as a gateway.

Section of the nest reveals, besides passages and galleries, a small chamber, across which is spread, like a spider's web, a network of squares spun by the insects. In each of these squares, supported by the web, sits one of the honey-secreting ants (II.). Here the honeymakers live in perpetual confinement, and receive a constant supply of flowers, pollen, &c., which is continually being brought them by I., and which, by a process of digestion and secretion, they convert into honey. It is particularly noteworthy that in this truly wonderful exhibition of social co-operation, the black and yellow workers appear to belong to two distinct genera; for hitherto this is the only case known of two distinct species of animals co-operating for a common end.

Ecitons. We have lastly to consider the most astonishing insects, if not the most astonishing animals, in the world. These are the so-called 'foraging,' or, as they might more appropriately be called, the military ants of the Amazon. They belong to several species of the same genus, and have been carefully watched by Bates, Belt, and other naturalists. The following facts must therefore be regarded as fully established.

Eciton legionis moves in enormous armies, and everything that these insects do is done with the most perfect instinct of military organisation. The army marches in the form of a rather broad and regular column, hundreds of yards in length. The object of the march is to capture and plunder other insects, &c., for food, and as the well-organised host advances, its devastating legions set all other terrestrial life at defiance. From the main column there are sent out smaller lateral columns, the composing individuals of which play the part of scouts-branching off in various directions, and searching about with the utmost activity for insects, grubs, &c., over every log and under every fallen leaf. If prey is found in sufficiently small quantities for them to manage alone, it is immediately seized and

carried to the main column; but if the amount is too large for the scouts themselves to deal with, messengers are sent back to the main column, whence there is immediately despatched a detachment large enough to cope with the requirements. Insects or other prey which, when killed, are too large for single ants to carry, are torn in pieces, and the pieces conveyed back to the main army by different individuals. Many insects in trying to escape run up bushes and shrubs, where they are pursued from branch to branch and twig to twig by their remorseless enemies, till on arriving at some terminal ramification they must either submit to immediate capture by their pursuers, or drop down amid the murderous hosts beneath. As already stated, all the spoils which are taken by the scouts, or by the detachments sent out in answer to their demands for assistance, are immediately taken back to the main army, or column. When they arrive there they are conveyed to the rear of that column by two smaller columns of carriers, which are constantly running in two double rows (one of each being laden and the other not) on either side of the main column. On either side of the main column there are also constantly running up and down a few individuals of smaller size, lighter colour, and having larger heads than the other ants. These appear to perform the duty of officers, for they never leave their stations, and while actively running up and down the outsides of the column, they seem intent only on maintaining order in the march-stopping every now and then to touch some member of the rank and file with their antennæ, as if giving directions.

When the scouts discover a wasp's nest in a tree, a strong force is sent out from the main army, the nest is pulled to pieces, and all the larvæ in the nest are carried by the carrier-columns to the rear of the army, while the wasps fly around defenceless against the invading multitudes. Or, if the nest of any other species of ant is found, a similarly strong force is sent out, or even the whole army may be deflected towards it, when with the utmost energy the innumerable insects set to work to sink shafts and dig mines till the whole nest is rifled of its contents. In these mining operations the Ecitons work with an extraordinary display of organised co-operation; for those low down in the shafts do not lose time by carrying up the earth which they excavate, but pass on the pellets to those above, and the ants on the surface, when they receive the pellets, carry them only just far enough to insure that they shall not roll back again into the shaft, and, after having deposited them at a safe distance, immediately hurry back for more.

The Ecitons have no fixed nest themselves, but live, as it were, on a perpetual campaign. At night, however, they call a halt and pitch a camp. For this purpose they usually select a piece of broken ground, in the interstices of which they temporarily store their plunder. In the morning the army is again on the march, and before an

hour or two has passed not a single ant is to be seen where thousands and millions had previously covered the ground.

The habits of E. humana and E. drepanophora are in general similar to those of the species just described. The latter, however, march in a narrower column (only four to six deep), which is therefore proportionally longer-sometimes extending to over half a mile. Bates tried the effect of interfering with a column of this species by abstracting an individual from it. News of the disturbance was quickly communicated to a distance of several yards to the rear, and the column at that point commenced retreating.' It was also this species that the same naturalist describes as enjoying periods of leisure and recreation when they call a halt in the sunny nooks of the forest.' On such occasions

the main column of the army and the branch columns 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 slowly about, others were brushing their antenna with their fore feet; but the drollest sight was their cleaning each other. . . . It is probable that these hours of relaxation and cleansing may be indispensable to the effective performance of their harder burdens; but whilst looking at them, the conclusion that they were engaged merely in play was irresistible.

E. prædator differs from the others of its genus in not hunting in columns, but' in dense phalanxes consisting of myriads of individuals.'

Nothing (says Bates) in insect movements is more striking than the rapid marchi of these large and compact bodies. Wherever they pass, all the rest of the animal world is thrown into a state of alarm. They stream along the ground and climb to the summit of all the lower trees, searching every leaf to its apex, and whenever they encounter a mass of decaying vegetable matter where booty is plentiful they concentrate, like other Ecitons, all their forces upon it, the dense phalanx of shining and quickly-moving bodies, as it spreads over the surface, looking like a flood of dark-red liquid. They soon penetrate every part of the confused heap, and then, gathering together again in marching order, onward they move.

A phalanx occupies from four to six square yards of ground, and the ants composing it do not move altogether in one straightforward direction, but in variously spreading contiguous columns, now separating a little from the general mass, now reuniting with it. The margins of the phalanx spread out at times like a cloud of skirmishers from the flanks of the main army.'

Two species of Eciton are totally blind, and the habits of these differ from those above described in that they march exclusively under covered roads or tunnels. The van of the column is constantly engaged in rapidly constructing the tunnels through which the army or regiment advances as quickly as they are made. Under the protection of these covered ways the ants travel at a surprising rate, and when they reach a rotten log or other promising hunting-ground, they pour into all the crevices, &c., in search of prey. Bates says:

The blind Ecitons, working in numbers, build up simultaneously the sides of their convex arcades, and contrive, in a wonderful manner, to approximate them and fit in the key-stones without letting the loose uncemented structure fall to pieces. There was a very clear division of labour between the two classes of neuters in these blind species. The large-headed class . . . act as soldiers, defending the working community (like soldier termites) against all comers. Whenever I made a breach in one of their covered ways, all the ants underneath were set in commotion, but the worker-minors remained behind to repair the damage, whilst the large-heads issued forth in a most menacing manner.

These two blind species of Eciton are particularly interesting from the fact that in a part of the world so remote from them as Western Africa there is another genus of military ant, also blind, which in all its habits closely resembles the blind Ecitons of Brazil. For, like the latter, Annornia arcens march in long close columns through tunnels, have no fixed nest, but make temporary halts in shaded places, and are no less organised, remorseless, and irresistible than their American congeners. In one curious particular, however, they differ; the relative position of the marchers and the carriers is reversed, for here the carrier columns occupy the middle place, while the marching columns with their officers occupy the flanks. When overtaken by a sudden African rain-storm, these ants congregate in a close mass, with the younger ants in the centre; they thus form a floating island.

It is remarkable that ants of different hemispheres should manifest so close a similarity with respect to all these wonderful habits. The Chasseur ants of Trinidad, and, according to Madame Merian, the ants of Visitation of Cayenne, also display habits of the same kind.

Special instances of the display of high intelligence.—I shall conclude this brief résumé of the more important facts at present known concerning the psychology of ants with a few selected observations of the display of high intelligence. It is always difficult to draw the line between instinct and reason, between adjustive action due to hereditary or purposeless habit, and adjustive action due to individual and purposive adaptation. But we may be least diffident in accepting as evidence of the latter cases where animals exhibit a power of adapting their actions to meet the requirements of novel circumstances or circumstances which cannot be supposed to have been of sufficiently frequent occurrence in the life-history of the species to have developed instincts of mechanical response in the individual. It is in view of this consideration that the following instances are selected.

Ebrard records in his Etudes de Mœurs an observation of his own on F. fusca. The ants were engaged in building walls, and when the work was nearly completed there still remained an interspace of 12 or 15 mms. to be covered in. For a moment the ants were thrown out, and

seemed inclined to leave their work, but soon turned instead to a grass-plant