Chapter V: Introduction (2)

[7] It may not be uninteresting after this account of the labours of the Mason-Ants, to give a sketch of the manner in which the Termites, or what have been termed by travellers, White Ants, so abundant in Africa, construct their dwelling. Compared with the Architects, their habitations are of an astonishing magnitude; they frequently exceed twelve feet in height, and are so firmly cemented as to bear the pressure of several men at the same time. It often happens that, whilst a herd of wild cattle are quietly grazing below, one of their body is stationed on them as sentinel, to give timely notice of approaching danger. The Termites begin constructing their habitations, by raising, at little distances from each other, several turrets of compact clay in the shape of sugar-loaves: upon these they erect others; those in the centre run to the greatest height: they afterwards cover in the spaces between them, and then take down the sides of all the inner turrets, leaving only the upper portion to form the cupola or dome, making use of the clay they thus procure, in the formation of the several chambers intended for magazines, nurseries, &c. The nurseries are entirely composed of wooden materials, enclosed in chambers of clay, usually half an inch in width, ranged around, and as close as possible to the royal apartment. The royal chamber, which, with the rest, are arched over, occupies as nearly as possible the centre of the building, and is on a level with the surface of the ground; it is at first only an inch in length, but increases in size with that of the Queen, until it extends to six or more inches. In this chamber the King and Queen are retained close captives; it is impossible they can ever quit it; the entrance only allowing of the passing and repassing of the Soldiers and Labourers (the Queen, in the last stage of her pregnancy, is 1000 times the weight of the King, and equal in bulk to about 20,000 Labourers, although, on her first appearance as a winged insect, she equalled only in bulk about 30 Labourers,--her abdomen increases from half an inch to three inches in length, and she lays, according to Smeathman, as many as 80,000 eggs in the course of 24 hours: hence the necessity for the numerous attendants by whom she is continually surrounded.) In an Ant-Hill of such extensive size, and where there is such an infinity of chambers to accommodate its numerous inhabitants, there must be of necessity a vast number of subterraneous and winding passages. These passages, which conduct to the upper parts of the dome, are carried in a spiral manner round the building, for the Labourers find it extremely difficult to ascend in a less circuitous direction. Very frequently, however, to shorten the distance to the upper nurseries, where they have to take the eggs, they project an arch of about ten inches in length, and half an inch in breadth, grooved or worked into steps, on its upper surface to allow of a more easy passage. When these insects quit their nest on any expedition, they construct covered galleries of clay which sometimes run to a considerable distance, and under this they continue their extensive and highly dreaded depredations.--T.

3. ARCHITECTURE OF THE DARK ASH-COLOURED ANTS.

These Ants, which are fully described in the Appendix, are distinguished, according to Latreille, by their having the body, head, and abdomen, of a shining dark ash-colour, the base of the antennæ and the feet reddish, the scale large and nearly triangular, and three small _ocelli_ or simple eyes.

The Ash-coloured Ants build in a manner very different from the Brown Ants. We have already seen from the description of their dwelling, that, in comparison to the latter, it is exceedingly simple and heavy in its construction. This simplicity, however, was better adapted to my object,--that of examining, if possible, how many ants could concur in the execution of the same design, and how far they appeared to understand each other in the general progress of their labour;--that of discovering also, if they acted in concert, or independently of each other; of their own accord, or from some general impulse. I do not flatter myself that I have solved these important questions, but the facts I am about to adduce, will, at least, serve to elucidate this subject.

When the Ash-coloured Ants seem desirous to give greater elevation to their dwelling, they commence, by placing over the roof a thick layer of earth, which they bring from the interior. It is here they trace _en creux et en relief_, the plan of a new story; they, at first, form here and there little dykes more or less close to each other, and of a breadth proportioned to the use for which they are designed: they give them nearly equal depth, for the most part equalling their breadth: the masses of earth left between them, serve afterwards, for the foundation of the inner walls. Having removed all the useless earth from the bottom of each chamber, and reduced to their proper thickness the foundation of the walls, the architects have nothing more to do, than to increase the height of their building, and cover over with a ceiling the several apartments.

After witnessing the manner in which these ant-hills are constructed, I was aware that the best and only mode of attaining a correct knowledge of their organization, was that of following individually the conduct of the Labourers engaged in erecting them. My journals are filled with observations of this nature. I extract a few that seem to possess some interest. I shall at present describe the operations of a single ant that I observed sufficiently long to satisfy my curiosity.

One rainy day, I observed a Labourer digging the ground near the aperture which gave entrance to the ant-hill. It placed in a heap the several fragments it had scraped up, and formed them into small pellets, which it deposited here and there upon the nest. It returned constantly to the same place, and appeared to have a marked design, for it laboured with ardour and perseverance. I remarked a slight furrow, excavated in the ground in a straight line, representing the plan of a path or gallery. The Labourer, the whole of whose movements fell under my immediate observation, gave it greater depth and breadth, and cleared out its borders; and I saw, at length--in which I could not be deceived--that it had the intention of establishing an avenue which was to lead from one of the stories to the under-ground chambers. This path, which was about two or three inches in length, and formed by a single ant, was opened above, and bordered on each side by a buttress of earth: its concavity _en forme de gouttiere_ was of the most perfect regularity; for the architect had not left an atom too much. The work of this ant was so well followed and understood, that I could almost to a certainty guess its next proceeding, and the very fragment it was about to remove. At the side of the opening where this path terminated, was a second opening to which it was necessary to arrive by some road. The same ant engaged in and executed alone this undertaking. It furrowed out and opened another path, parallel to the first, leaving between each a little wall of three or four lines in height.

Those ants who lay the foundation of a wall, a chamber, or gallery, from working separately, occasion now and then a want of coincidence in the parts of the same or different objects. Such examples are of no unfrequent occurrence, but they by no means embarrass them. What follows proves that the workman, on discovering his error, knew how to rectify it.

A wall had been erected with the view of sustaining a vaulted ceiling, still incomplete, that had been projected from the wall of the opposite chamber. The workman who began constructing it, had given it too little elevation to meet the opposite partition upon which it was to rest. Had it been continued on the original plan, it must infallibly have met the wall at about one-half of its height, and this it was necessary to avoid. This state of things very forcibly claimed my attention; when one of the ants, arriving at the place, and visiting the works, appeared to be struck by the difficulty which presented itself; but this it as soon obviated, by taking down the ceiling and raising the wall upon which it reposed. It then, in my presence, constructed a new ceiling with the fragments of the former one.

When the ants commence any undertaking, one would suppose that they worked after some preconceived idea, which indeed would seem verified by the execution. Thus, should any ant discover upon the nest, two stalks of plants, which lie cross-ways, a disposition favourable to the construction of a lodge; or some little beams that may be useful in forming its angles and sides, it examines the several parts with attention, then distributes with much sagacity and address parcels of earth, in the spaces, and along the stems, taking from every quarter materials adapted to its object, sometimes, not caring to destroy the work that others had commenced; so much are its motions regulated by the idea it has conceived, and upon which it acts, with little attention to all else around it. It goes and returns, until the plan is sufficiently understood by its companions.

In another part of the same ant-hill, several fragments of straw seemed expressly placed to form the roof of a large house; a workman took advantage of this disposition: these fragments lying horizontally, at half an inch distance from the ground, formed, in crossing each other, an oblong parallelogram. The industrious insect commenced, by placing earth in the several angles of this _carpentering_ work, and all along the little beams of which it was composed. The same workman afterwards placed several rows of the same materials against each other, when the roof became very distinct. On perceiving the possibility of profiting by another plant, to support a vertical wall, it began laying the foundations of it; other ants having by this time arrived, finished in common what this had commenced.[8]

[8] I have often been surprised at the ingenuity of these little creatures, in availing themselves of contiguous blades of grass, stalks of corn, &c., when they wish to enlarge the boundaries of their abode. As these are usually met with in the erect position, they are admirably calculated for pillars; they, therefore coat them over with a fine paste of earth, giving them, by additional layers, the solidity they judge necessary for the work on which they are engaged: they then leave them to be consolidated by the wind, and afterwards spring a number of arches, from pillar to pillar, and thus form an extensive saloon. Should they be, at any time, in want of small apartments, they have only to prepare a quantity of moistened earth, and by placing this between the pillars, and carrying it up to the roof, leaving here and there an aperture for entrance, their object is completely attained.--T.

From these observations, and a thousand similar, I am convinced that each ant acts independently of its companions. The first who conceives a plan of easy execution, immediately gives the sketch of it; others have only to continue what this has begun, judging, from an inspection of the first labours, in what they ought to engage. They can all lay down plans, and continue to polish or retouch their work as occasion requires. The water furnishes the cement they require, and the sun and air harden the materials of which their edifice is composed. They have no other chisel than their teeth, no other compass than their antennæ, and no other trowel than their fore-feet, of which they make use in an admirable manner, to affix and consolidate the moistened earth.

These, then, are the material and mechanical means which they employ in their building. In following an instinct purely mechanical, they might execute with precision, a geometrical and invariable plan, construct walls of equal length and breadth, vaulted ceilings, whose curve would only require a servile _obeissance_, and we should have been but moderately surprised by their industry: but to form these irregular domes, composed of so many stories; to distribute in a convenient, yet varied manner, the apartments they include, and to seize the most favourable time for their labours, but especially to vary them according to circumstances; to profit by the _points d’appui_ that may present themselves; and to judge of the advantage of such and such operations, is it not necessary they should be endowed with faculties closely approaching intelligence, and that, far from considering them as automatons, Nature allows them to perceive the intention of those labours in which they have been engaged?[9]

[9] For several curious particulars relative to the instinct of insects, I refer to the _Introduction to Entomology, by Messrs. Kirby and Spence_, vol. ii. p. 465.--This work I cannot too strongly recommend to the notice of my readers; since it abounds in a variety of interesting information, and possesses the no small advantage of being equally amusing as instructive.--T.

I could readily bring forward numberless examples of the industry of ants, in still mentioning after what manner several other species construct their abode; but, not to abuse or weary the patience of my readers, I shall not enter into a detail of the labours of the Field Ants, who build little chambers, one above the other, along the stems of plants, and who can, in time of need, connect grains of sand, by juxta-position alone, or by the admixture of a little moistened earth; nor of those of the Sanguine Ant, who are enabled to form from earth, dry leaves, and other materials, a compact tissue, difficult to break, and impenetrable to water; nor of those covered galleries, which the Brown Ants construct with earth, conducting from their nest to the feet of trees, and sometimes even to the origin of the branches, for the purpose of arriving with greater security at the places where they find their food.

4. ARCHITECTURE OF ANTS THAT FORM THEIR HABITATION IN TIMBER.[10]

[10] “Some ants” says Kirby, “form their nests entirely of the leaves of trees. One of these was observed by Sir Joseph Banks in New South Wales, which was formed by glueing together several leaves as large as a hand. To keep these leaves in a proper position, thousands of ants united their strength, and if driven away, the leaves spring back with great violence.” Latreille speaks of an ant which is met with at Cayenne (_F. bispinosa_) that forms its nest of a great quantity of down, which it removes from the seeds of a species of the cotton-tree. Madame Merian, in her “_Insectes de Surinam_,” speaks of an ant, which, in Tobago, is called the _parasol ant_. They are in the habit of cutting out circular pieces from the leaves of trees and plants (in this respect resembling the _apis papaveris_), and carrying them off to their nest. When thus engaged, they bear some resemblance to individuals walking with parasols, hence their name. Smeathman informs us, that one species of the Termites, or what are commonly known under the name of White Ants (_T. arborum_) builds its nest among the branches of trees; and we learn from M. de Laubere, that in that part of Siam which is exposed to inundations, all the ants construct their habitations in trees.--T.

Is it not a matter of astonishment, that Nature should have given to insects of the same genus, manners so varied, and an industry so widely different? Ants furnish us with one of the most striking examples of this kind. We have just completed a sketch of the several species of Mason-ants; each building in a different manner, and offering some striking peculiarities in the style and mode of their architecture. That of the Fallow-ants is founded upon different principles, and the industry of those who excavate their dwelling in wood, has no point of resemblance with that of the species of which we have lately treated. This tribe of ants includes several species; and we still observe in their architectural labours very sensible shades of difference: all these insects enter into the first of the nine divisions into which Latreille has distributed ants, it includes the Brown, the Ash-coloured, the Fallow, the Mining, the Sanguine, the Fuliginous, and the Yellow Ant, &c. These ants possess the same exterior organs, a similarity of the means employed in constructing their dwellings, and resemblances in figure, which have occasioned them to be placed under the same division; their instinct, however, places them at a considerable distance from each other, plainly showing that we cannot always form a correct judgment of the manners and customs of insects from analogy.

The labours of those ants that inhabit trees, or what we may term Timber Ants, are less open to general observation than those already described, and have, in consequence, received but little attention from naturalists.

The ant holding the first rank in this division, is, the Fuliginous, so called on account of its colour. It is of a shining black, and is two lines in length; its republics, composed of a great number of individuals, are less common than those of which we have hitherto spoken.

Let us figure to ourselves the interior of a tree entirely sculptured or hollowed out, consisting of numberless stories, more or less horizontal, whose floors and ceilings are at five or six lines’ distance from each other, and as thin as a card, supported at one time by vertical partitions, forming an infinity of chambers; at another time, by a series of small slender columns, allowing us to observe between them the extent of an almost entire story; the whole, composed of a blackish, and as it were smoked wood; and we shall have a just idea of the cities of these ants.

The greater number of the vertical partitions, which divide each story into compartments, are parallel; they follow the course of the ligneous layers, and are always concentrical, which gives to their work some degree of regularity. The floors, generally speaking, are horizontal. The little columns are from one to two lines in thickness, more or less round, of a height equal to that of the story they support, larger above and below than in the middle, a little flattened at the capital and base, and ranged in regular lines, since they have been worked out in the parallel partitions. What numerous apartments! What a series of lodges, halls and corridors do these insects not form by their own unsupported industry; and what labour in so great an undertaking does it not cost them!

The wood, in which ants of this species excavate these labyrinths, takes a blackish hue:--does this arise from the extravasated fluids of the tree entering into combination with the external air, or from the emanation of the ants themselves, the odour of which may perhaps have some influence; or do the layers of wood, exposed by these insects, undergo any decomposition from combining with the formic acid? I cannot decide this question; but I rest well assured, that the wood hewn by these insects, is always blackish externally, and even takes the same colour internally, provided it be very thin, preserving only its natural colour when it has any degree of thickness. It appears that the oak, willow, and other trees in which these ants establish themselves, equally take these colours. I have often observed several other species of ants lodged in the interior of trees, but the wood never presented the same appearance. I have also often noticed at the foot of those which were inhabited by Fuliginous Ants, a very abundant and blackish liquid:--to what must this be attributed? The vegetation of these trees does not appear in the slightest degree affected by the labours of these insects.

It would be a highly interesting sight, could we observe ants occupied in carving the wood in which they fix their residence, we might then learn the origin of the black tint with which it is imbued; but the labourers of this species working always in the interior of trees, and desirous of being screened from observation, precludes every hope, on our part, of following them in their several occupations. I tried every expedient I could devise to surmount this difficulty; I endeavoured to accustom these ants to live and work under my inspection, but all my efforts were unsuccessful; they even abandoned the most considerable portion of their nest to seek some new asylum, and spurned the honey and sugar I offered them for nourishment. I was now, of necessity, limited to the inspection alone of these edifices; but by decomposing some of the fragments with care, I hoped to acquire some knowledge of their organization. Here, we perceive horizontal galleries, hidden in great part by their walls, which follow the circular direction of the ligneous layers; there, parallel galleries, separated by extremely thin partitions, having no communication except by a few oval apertures. Such is the nature of these works, remarkable for their delicacy and lightness.

In other fragments we notice avenues, opened laterally, including portions of walls and transverse partitions, erected here and there, within the galleries, so as to form separate chambers. When the work is further advanced, we always observe round holes, encased, as it were, between two pillars, cut out in the same wall. These holes in course of time become square, and the pillars, originally arched at both ends, are worked into regular columns by the chisel of our sculptors. This, then, is the second specimen of their art. This portion of the edifice will probably remain in this state.

But here are fragments differently wrought, in which these same partitions, pierced now in every part, and hewn skilfully, are transformed into colonnades, which sustain the upper stories, and leave a free communication throughout their whole extent. We can readily conceive how parallel galleries hollowed out upon the same plan, and the sides taken down, leaving only from space to space what is necessary to sustain their ceilings, may form an entire story; but as each has been pierced separately, the flooring cannot be very level: this, however, the ants turn to their advantage, since these furrows are better adapted to retain the larvæ that may be placed there.

The stories constructed in the great roots offer greater irregularity than those in the very body of the tree, arising, either from the hardness and interlacing of the fibres, which renders the labour more difficult, and obliges the labourers to depart from their accustomed manner, or from their not observing in the extremities of their edifice the same arrangement as in the centre: whatever it be, we still find horizontal stories, and numerous partitions. If the work be less regular, it becomes more delicate; for the ants, profiting by the hardness and solidity of the material, give to their building an extreme degree of lightness. I have seen fragments of from eight to ten inches in length and of equal height, formed of wood as thin as paper, containing a number of apartments, and presenting the most singular appearance. At the entrance of these apartments, worked out with so much care, are very considerable openings; but, in place of chambers, and extensive galleries, the layers of the wood are hewn in arcades, allowing the ants a free passage in every direction. These may be regarded as the gates or vestibules conducting to the several lodges.

Fig. 3. and 4., Pl. I., give but a very imperfect idea of the labours of these insects. The first represents a fragment taken from the trunk of an oak inhabited by Fuliginous Ants; the second, a small portion of their nest, taken from the roots of the same tree. To judge properly of these fragments, we should place them in every position, we shall then better observe their singular organization.

The Red Ant, a little larger than the preceding, forms a lodging in trees, very analagous to the above, but upon a much smaller scale. Their dwelling consists of stories more or less developed; some divided into little chambers or lodges, the walls of which are remarkably thin; others sustained by an infinity of little columns, resembling, in size and colour, those of which we have already spoken. The wood, however, is not blackened, as is the case with that excavated by the Fuliginous Ants, but retains its original colour. It is commonly less hard, and of the consistence of cork.

But what is most remarkable in the history of Red Ants is, that they are not only carvers, but even skilful masons. They more frequently fix their residence in the earth. This is not, however, the only species that can, in time of need, display more than one talent in this department. We are about to notice two kinds of ants which also enjoy this privilege, the Ethiopian and the Yellow Ant. They have also an art peculiar to them, of which I have not yet treated, and which must be regarded as belonging to the architecture of ants.

5. ARCHITECTURE OF THOSE ANTS THAT FORM THEIR RESIDENCE OF SAW-DUST, DECAYED TIMBER, &C.

The Ethiopian Ants, thus named, on account of their jet-black colour, hollow out extensive lodges and long galleries in the oldest trees; but if their works are proportioned to their size, which is greater than that of other ants, they scarcely represent the infancy of the art by the manner in which they are executed. What is most remarkable in their industry is, the use they make of the wood fallen into powder at the foot of the tree they inhabit, to stop up every chink in the flooring of their houses, to close useless passages, and to make compartments in those labyrinths which are too spacious.

The Yellow, one of the mason ants, shows great skill in the employment of this substance, when it establishes its residence in a hollow tree; it constructs entire stories with decayed wood, selecting the finest particles, which, on being mixed up at the bottom of the tree with a little earth and spider’s web, forms a mass of the consistency of _papier mâché_. This industry recalls to mind that of wasps, as the labours of the Mason and Timber Ants bring to our recollection those of the Mason and Timber Bees.

The class of hymenopterous insects, the richest of all in varied industry, in original manners and customs, in curious instinct, offers, continually, similarities and contrasts; connections between genera the farthest removed, and striking differences between species the most approximate. The moral condition of these insects does not appear to follow their physical condition; a truth of some importance to animal physiology.

CHAP. II.

OF THE EGGS, LARVÆ, AND PUPÆ OF ANTS.

The exterior of ant-hills, their form and construction, have hitherto entirely occupied us: it was, however, necessary to commence by establishing the ants in their abode previous to describing the rest of their labours. The object which will now evidently create some interest, is that solicitude the workers evince for the object of their charge, and the maternal attention they bestow upon them from the period of their quitting the egg to that of their complete developement.[1] Although several naturalists have studied the metamorphosis of ants, and described the principal circumstances connected with it, yet we are about to examine, under new relations, the developement and education of these insects in their different states. The history of the egg had entirely escaped their researches, as well as several particulars in the history of the pupæ and larvæ.

[1] It would be perhaps more regular to speak of the fecundation of ants, before making known the care and affection they evince for their young. This plan, from which we could not well depart, in speaking of insects that lead a solitary life, is not so natural, when treating of numerous and permanent republics, such as those of ants. It would have been difficult to have mentioned every circumstance connected with the reproduction of the species, before describing the interior of their habitations, and the method I found the most successful in my observations. The education of their young, being the chief end of all their labours, offers, in part, a picture of the manners of these industrious insects. It is for this reason, the plan I now follow appeared the best to elucidate subsequent remarks.--A.

My predecessors, not having made use of a glazed apparatus to observe what passed in the interior of ant-hills, had but very rarely seen these insects engaged in their household occupations; and this was not so easy of accomplishment as it at first appeared.

These insects, although possessing so little timidity, and regardless, as it concerns themselves, of the several changes in the weather, evince the greatest concern for their little ones. For beings, so delicately formed, they dread the slightest variations of the atmosphere, are alarmed at the least danger which threatens them, and seem particularly anxious to withdraw them from our notice.

I was in my first attempts continually disappointed, from the great repugnance they manifested in allowing the light to penetrate their abode: whenever I attempted to glaze their apartments, or to lay open to view any of their halls or passages, if they did not completely abandon them, they at least prevented me from following them in their in-door labours. At one time they would darken, by a heap of different materials, all the halls which admitted the light; at another time, as if conscious that the glass, notwithstanding its transparency, could guard them from the external air, and that nothing was wanting to render it a true wall, but the power of excluding that glaring light, at all times so disagreeable to them, they preserved entire all the galleries contiguous to it, taking the sole precaution of covering it over with a layer of moistened earth, which effectually hindered further observation.

Thus disappointed, I employed a method more simple, though more effectual:--I removed a portion of the ant-hill, and then placed over the remainder a thin flat board inclined to the south; the ants, attracted by the heat brought their little ones to this place. By removing this outside shutter or _contrevent_, I could ascertain the progress in their growth, although the workers, on being disturbed, hastened to convey them to their under-ground quarters.

I was often obliged to vary the means I employed; for the ants, soon wearied by my visits, still baffled all my efforts, by making a true wall of earth behind the _contrevent_. After having for some time attended to the manners and habits of these insects, I found that we might accustom them by degrees to suffer the entrance of the light in their abode; but it was necessary, notwithstanding, to use much caution. What succeeded with me the best, was that of forming an oblong opening in the middle of a table, and affixing underneath, a double frame, glazed on its two longest sides, and opened only at the upper part, which communicated with this aperture. These frames (fig. 1. Pl. I.) being furnished with shutters, permitted me, either to observe the ants, or to favour them in their taste for obscurity. This done, I scattered all the materials of a nest of Fallow Ants upon the table, and left them at liberty to arrange them at the bottom of the glazed box, which they did in such a manner, that it was easy to observe all their galleries, and the apartments to which they led. I at length covered over the whole of the materials with a large bell-glass, in order that I might witness the movements of my prisoners, as well inside as on the outside, and at the same time guard against their escape. But when I saw they were accustomed to their fate, and did not seek to leave their prison, I allowed them free issue from under the bell-glass, and the liberty of running over the platform upon which it rested, taking only the precaution of plunging the feet of the table in vessels filled with water, to arrest the ants in their passage, should they attempt to escape.

This apparatus, and several others of which the explanation would be long and tedious, had all the success I wished. I observed, with much pleasure, that the ants continued to take care of the larvæ, which proved, that in taking them, in some respects, from the state of nature, I had not too much disturbed them. This gave me reason to hope, that I should observe, in its greatest extent, all the care they took of the rising generation.

I did not, however, always keep to these artificial means. I compared, as often as possible, the conduct of my prisoners, with that of those ants inhabiting and ranging about the fields, and as I never remarked any sensible difference in their manner of acting, I concluded I could trust the results obtained by means of my glazed apparatus.

Let us now open the shutter which conceals from us the interior of the ant-hill, and let us see what is passing there.

Here, the pupæ are heaped up by hundreds in their spacious lodges; there, the larvæ are collected together, and guarded by workers. In one place, we observe an assemblage of eggs, in another place, some of the workers seem occupied in following an ant of a larger size than the rest;--this is the mother, or at least one of the females, for there are always several in each ant-hill:--she lays as she walks, and the guardians, by whom she is surrounded, take up her eggs, or seize them at the very moment of her laying them; they collect them together, and carry them in little heaps in their mouths.[2] On looking a little closer, we find that they turn them continually with their tongues; it even appears, they pass them one after the other between their teeth, and thus keep them constantly moistened. Such is the first _aperçu_ which my glazed apparatus offered.

[2] The eggs of ants are so remarkably minute, that there would seem an absolute necessity of their being held together by some glutinous matter, otherwise, it would render the removal of such small bodies in the mandibles of ants almost impossible; the mandibles being so constituted as not to be brought into that close contact necessary for this operation.--T.

Having directed my close attention to these eggs, I remarked they were of different sizes, shades, and forms. The smallest were white, opake, and cylindrical; the largest, transparent, and slightly arched at both ends; those of a middle size were semi-transparent. In holding them up to the light, I observed a sort of white oblong cloud; in some, a transparent point might be remarked at the superior extremity; in others, a clear zone above and underneath the little cloud. The largest presented a single opake and whitish point in their interior. There were some whose whole body was so remarkably clear, as to allow of my observing very distinctly the rings. In fixing my attention more closely upon the latter, I observed the egg open, and the larva appear in its place.

Having compared these eggs with those just laid, I constantly found the latter of a milky whiteness, completely opake, and smaller by one-half; so that I had no reason to doubt of the eggs of ants receiving a very considerable increase in size; that in elongating, they become transparent, but do not at this time disclose the form of the worm which is always arched.

To be convinced of the truth of this statement, I viewed these eggs with the microscope; I also measured them, and having separated them from each other, found the longest to be those only in which the worms were disclosed in my presence. If I removed them from the workers, before they had attained their full length and transparency, they dried up, and the worms never quitted them.

Is it, then, to the care which the workers take in passing them across their mouths, that we must attribute the secret of their preservation? Do these eggs require this humidity, or do they absorb a part of it, to furnish nourishment to the little worms they contain? It appears at least highly probable; and the observations of M. Reaumur give weight to this opinion. I have discovered in his writings, that there are other eggs, which also increase in size,--as those lodged in the galls of different trees, which are occasioned by _Cynips_[3], or other insects of the same kind.

[3] To these insects we are indebted for that valuable article of commerce, the gall-nut. The _Cynips_ is furnished with a finely-pointed instrument, with which it wounds the leaves and other parts of the tree, for the sake of depositing its eggs. The puncture of the leaves, &c. gives rise to those excrescences termed galls, which not only form the habitation, for a considerable period, of the infant insect, but serve it the whole time of its imprisonment for food. On examining the galls, some will be found to have an opening in them; these are they, from which the fly has escaped: others, that want this aperture, will be found to contain the insect, either in its larva, pupa, or imago state; for it appears these several changes, at least with some of the species, take place within the body of the gall.--T.

“It ought not,” says this exact and judicious observer, “to be passed by in silence, that the egg which I found in the gall appeared to me considerably larger than the eggs of the same species, when they proceed from the body of the fly, or even when they are taken from the body of the impregnated or mother-fly, near the time of their being laid. The whole of those I took from the abdomen of the flies I killed were remarkably small; it therefore appeared certain, that the egg would have increased, and indeed had increased, in the gall.”

We are only in the habit of observing eggs surrounded by a covering incapable of extension; but why is it that those eggs, which nature has enclosed, in a flexible membrane, do not increase? The envelope of the egg may, in this instance, be compared to the membrane which includes the human fœtus, and those of quadrupeds.

Nature has formed the eggs of some other insects in such a manner, that they are also capable of increase: such are, according to M. Vallisnieri, the eggs of the _Tenthredo_, which produce those larvæ that feed upon the rose.[4]

[4] Latreille alludes to this increase in the size of the eggs, both in these insects, and the _Cynips_.--T.

These remarkable examples authorise me in admitting an increase in size, in the eggs of ants, as fully proved; although it may not be exactly under the same circumstances as those of which the philosopher I have just quoted speaks; but if they are not surrounded with a liquid, or preserved from the influence of the external air, their pellicle, moistened every instant by the workers, may preserve a certain degree of suppleness, and the faculty of extension, according to the developement of the worm they enclose.

At the end of fifteen days, the little worm is seen to quit the shell: its body is then perfectly transparent, and presents only a head and rings, without any rudiment of feet or antennæ. The insect, at this period, is completely dependant upon the workers.

I have been enabled to observe, through the glasses of my artificial ant-hill, the great care taken of these little worms, which bear also the name of Larvæ. They were generally guarded by a body of ants, who, raised upon their feet, with their abdomen brought between these members, were prepared to cast their venom upon all intruders, whilst, here and there, other workers were engaged in clearing the passages, by removing the materials which were out of place; a great number of their companions taking at the same time their repose, and appearing to be fast asleep: but a busy scene occurred at the moment of transporting their little ones to enjoy the warmth of the sun. When the sun’s rays fell upon the exterior portion of the nest, the ants, who were then on the surface, descended with great rapidity to the bottom of the ant-hill, struck with their antennæ the other ants, ran one after the other, and jostled their companions, who mounted at the moment under the bell-glass, and redescended with the same speed, putting in their turn the whole colony in motion, so that we could observe a swarm of workers, filling up all the passages; but what proved still more their intention by these movements, was, the violence with which the workers sometimes seized, with their mandibles, those who did not appear to understand them, dragging them forth to the top of the ant-hill, and immediately leaving them, to go and seek those still remaining with the young.

As soon as the ants had intimation of the appearance of the Sun, they occupied themselves with the larvæ and pupæ; they carried them with all expedition above the ant-hill, where they left them exposed to the influence of the heat. Their ardour suffered no relaxation; the female larvæ (which are heavier, and much larger than those of the other cast) were carried, with some difficulty, through the narrow passages, leading from the interior to the exterior of the ant-hill, and placed in the sun, by the side of those of the workers and males. After remaining there a quarter of an hour, the ants again took them up, and sheltered them from the direct rays of the sun, by placing them in chambers, situated under a layer of straw, which did not entirely intercept the heat.

The workers, after having fulfilled the duties imposed upon them in regard to the larvæ, did not forget themselves; they sought, in their turn, to stretch themselves in the sun, lay upon each other in heaps, and seemed to enjoy some repose, but it was of no long duration. I observed a great number constantly employed on the surface of the ant-hill, and others engaged in carrying back the larvæ, in proportion as the sun declined. The moment of nourishing them being at length arrived, each ant approached a larva, and offered it food. “The larvæ of ants,” observes M. Latreille, “resemble, when they quit the egg, little white worms, destitute of feet, thick, short, and in form almost conical; their body is composed of twelve rings; the anterior part is slender and curved. We remark at the head two little horny pieces or hooks, too distant from each other to be regarded as true teeth; under these hooks we observe four little points or _cils_, two on each side, and a _mamelon_, or tubercular process, almost cylindrical, soft, and retractile, by which the larva receives its food.”[5]

[5] What a world of wonders is there not opened to our view, in the transformations the insect tribe undergo, from the period of their birth, to the full and complete development of their several organs. Unless well assured of the fact, how could we imagine the feeble helpless worm just described would ever become the industrious, enterprising ant, furnished with organs of motion and of flight. How devoid of probability would appear the statement, did we not possess evidence to the contrary, that the magnificent butterfly we see hovering from flower to flower, ever drew its origin from the creeping caterpillar. But these changes, surprising as they are, are yet equalled by other circumstances connected with the metamorphoses of insects, for with these changes in appearance, the animal alters its habits and mode of life. The butterfly in its first or larva state of existence eats voraciously, and in a manner greatly disproportioned to its size, devouring twice its weight of leaves in a day; in its second or pupa state, this inordinate appetite ceases, and all its active powers are suspended; in its third, imago, or perfect state, no longer bound to the spot that gave it birth, it takes a wider range, cleaves the regions of the air, and sips the nectar of flowers. That beautiful silver-winged insect (_Libellula_) now crossing our path, passed the first part of its existence as a water insect, and that little creature (_Ephemera_) we see sporting in the sun-beam, whose existence as a winged insect is limited only to a few hours, and seemingly with no other view than that of continuing its kind, has also passed the first period of its life in the same element. The common gnat, that so much annoys us in our evening walks, was originally an inhabitant of some stagnant pool. The beetle that flits along at even-tide, lay in a worm-like state for a considerable period, locked up in the caverned chambers of the earth, and--but why proceed, when the whole insect tribe, generally speaking, undergo such developements.--T.

The ants do not prepare for their larvæ _provisions de bouche_, as happens with several species of bees and other insects, which provide before-hand for the wants of their little ones; they give them every day the nourishment best suited to their condition; the instinct of the larvæ is sufficiently developed, to enable them to demand and receive their repast, in the same way as the young of birds receive it from their parents. When hungry, they erect their body, and search with their mouth that of the workers, who are appointed to nourish them. The ant then separates its mandibles, and allows them to take from its very mouth the fluids they seek.

I know not if these fluids undergo any change in the body of the workers, but I am far from believing it to be the case, since I have often seen the ants offer them nourishment, almost immediately after they had themselves taken it; perhaps honey and sugar dissolved in water. I presume, however, that the regimen is proportioned to the age and sex of each individual, that the aliment is more substantial the nearer the time of their metamorphosis, and that more is given to the larvæ of females than to those of the workers and males; but the questions which have reference to the quality and quantity of these aliments are of difficult solution: however, as it is of some importance to ascertain if the nourishment which the larva takes has any influence upon the development of the sexes in the females of ants, as obtains in bees, I purpose making some experiments by nourishing myself the larvæ of different species. Let us at present follow the workers in the last care they bestow upon the larvæ; it is not sufficient to lay them in the sun and give them food; it is still necessary to keep them remarkably clean. These insects, therefore, who in point of tenderness to the young committed to their charge, do not yield to any of the females of the larger animals, pass their tongue and mandibles continually over their bodies, and thus render them perfectly white.[6] The ants have also another occupation; that of extricating them from their cuticle, which becomes distended and soft at the period of their transformation.

[6] As these insects evince so much attachment to the charge committed to their care, I was desirous of ascertaining if they would show equal concern for the offspring of another species. For this purpose, I visited a nest inhabited by the little black ant, where there were only larvæ, and removed a few to a nest occupied by the yellow ant, containing only pupæ. Here they lay for a time unnoticed. At length, one or two of the ants took them up, with the intention of carrying them away, when another, who appeared stationed as centinel, ran violently against and overthrew them, thus occasioning them to relinquish their hold: this part of the nest was at length deserted, the larvæ were left where first deposited, and the centinel retired. At this time not a single ant was within view. In about five minutes a little troop sallied forth, and, as if acting under some general impulse, carried off their unwelcome visitors to one of their underground apartments. Visiting this nest from day to day, I never afterwards saw these larvæ, and therefore, conclude they had been set apart, where, from neglect, they had perished. Had the larvæ been brought up in common with those of their own family, I must have known it; for, as I before said, the nest contained pupæ only. In an after-visit to this nest, I reversed the experiment, by carrying away some of the pupæ, and placing them in the nest from which I had before taken the larvæ. This done, a similar scene took place. The pupæ were at first regarded with indifference. Some of the inhabitants then attempted a removal, to which there was, for a time, strong opposition. In a few minutes, however, they were carried off to the subterranean chambers. In these experiments, there was this slight difference: in the former instance, the ants retired, as it would seem, to deliberate; in the latter, they remained the whole time within sight, a little distance from the pupæ. Had the larvæ or pupæ been suffered to remain where first placed, this would have greatly embarrassed the ants in their daily operations, this being the spot where they were in the habit of bringing their young to enjoy the sun’s warmth. But why they should take them under-ground, in preference to carrying and depositing them beyond the nest, is a question I can only answer by supposing they there conveyed them to insure their certain destruction, and thus prevent further molestation.--T.

Previous to changing this skin, the larvæ spin themselves a silken covering or cocoon, (as is the case with many other insects,) in which in the form of pupæ, they prepare to undergo their last metamorphosis. This cocoon is of a cylindrical form, elongated, of a pale yellow colour, and very smooth and close in its texture. A remarkable circumstance for which no cause has been yet assigned is, that there are ants whose larvæ never spin; but this exception only holds with those species that possess a sting and two knots on the peduncle of the abdomen. Thus, there are some larvæ which undergo their change in a silken envelope, and others which become pupæ, without lying under the necessity of spinning or weaving one.[7]

[7] Among the spinning larvæ, there are some whose web is marked with a black point at one of the extremities, which has been taken for the remains of the skin of the pupæ, which they reject in their preceding state; but as I have found the cocoons, thus stained, before the larvæ they contained had undergone their metamorphosis, this supposition falls to the ground. I am fully convinced it is nothing more than the residue of the aliment, which these insects discharge a little time before their change.--A.

Gould is of our Author’s opinion; but Sir Edward King, who published a memoir on ants in an early number of the Philosophical Transactions conjectures, that it is a secretion cast out by the larva in its transformation.--T.

The larvæ of some ants pass the winter heaped up in the lowermost floor of their dwelling. I have found, at this period, very small larvæ in the nests inhabited by the Yellow Ant, the Field Ant, and some other species, but none, in those of the Fallow, Ash-coloured, and Mining Ants. Those that are to pass the winter in this state are covered with hair, which is not the case in summer; affording another proof of that Providence at which naturalists are struck at every step. We do not find the larvæ of males and females but in the spring; their transformation takes place in the beginning of summer.