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AN INTRODUCTION TO ENTOMOLOGY.

IMPERFECT SOCIETIES.

I see already, and I see it with pleasure, that you will not content yourself with being a mere collector of insects. To possess a cabinet well stored, and to know by what name each described individual which it contains should be distinguished, will not satisfy the love that is already grown strong in you for my favourite pursuit; and you now anticipate with a laudable eagerness, the discoveries that you may make respecting the history and economy of this most interesting department of the works of our Creator. I hail with joy this intention to emulate the bright example, and to tread in the hallowed steps of Swammerdam, Leeuwenhoek, Redi, Malpighi, Vallisnieri, Ray, Lister, Reaumur, De Geer, Lyonnet, Bonnet, the Hubers, &c.; and I am confident that a man of your abilities, discernment, and observation will contribute, in no small degree, to the treasures already poured into the general fund by these your illustrious predecessors.

I feel not a little flattered when you inform me that the details contained in my late letters relative to this subject, have stimulated you to this noble resolution.--Assure yourself, I shall think no labour lost, that has been the means of winning over to the science I love, the exertions of a mind like yours.

But if the facts already related, however extraordinary, have had power to produce such an effect upon you, what will be the momentum, when I lay before you more at large, as I next purpose, the most striking particulars of the proceedings of insects in society, and show the almost incredibly wonderful results of the combined instincts and labours of these minute beings? In comparison with these, all that is the fruit of solitary efforts, though some of them sufficiently marvellous, appear trifling and insignificant: as the works of man himself, when they are the produce of the industry and genius of only one, or a few individuals, though they might be regarded with admiration by a being who had seen nothing similar before, yet when contrasted with those to which the union of these qualities in large bodies has given birth, sink into nothing, and seem unworthy of attention. Who would think a hut extraordinary by the side of a stately palace, or a small village when in the vicinity of a populous and magnificent city?

Insects in society may be viewed under several lights, and their associations are for various purposes and of different durations.

There are societies the object of which is mutual defence; while that of others is the propagation of the species. Some form marauding parties, and associate for prey and plunder;--others meet, as it should seem, under certain circumstances, merely for the sake of company;--again, others are brought together by accidental causes, and disperse when these cease to operate;--and finally, others, which may be said to form proper societies, are associated for the nurture of their young, and, by the union of their labours and instincts, for mutual society, help, and comfort, in erecting or repairing their common habitation, in collecting provisions, and in defending their fortress when attacked.

Imperfect societies may be considered as of five descriptions:--associations for the sake of company only--associations of males during the season for pairing--associations formed for the purpose of travelling or emigrating together--associations for feeding together--and associations that undertake some common work.

"Nor wanting here to entertain the thought, Creatures that in communities exist, Less, as might seem, for general guardianship Or through dependance upon mutual aid, Than by participation of delight, And a strict love of fellowship combined. What other spirit can it be that prompts The gilded summer flies to mix and weave Their sports together in the solar beam, Or in the gloom and twilight hum their joy?"

"Some to the sun their insect wings unfold, Waft on the breeze, or sink in clouds of gold; Transparent forms, too fine for mortal sight, Their fluid bodies half dissolv'd in light; Loose to the wind their airy garments flew, Thin glittering textures of the filmy dew, Dipt in the richest tincture of the skies, Where light disports in ever mingling dyes, While every beam new transient colours flings, Colours that change whene'er they wave their wings."

The old Arabian fable, that they are directed in their flights by a leader or king, has been adopted: but I think without sufficient reason, by several travellers. Thus Benjamin Bullivant, in his observations on the Natural History of New England, says that "the locusts have a kind of regimental discipline, and as it were some commanders, which show greater and more splendid wings than the common ones, and arise first when pursued by the fowls or the feet of the traveller, as I have often seriously remarked." And in like terms Jackson observes, that "they have a government amongst themselves similar to that of the bees and ants; and when the king of the locusts rises, the whole body follow him, not one solitary straggler being left behind." But that locusts have leaders, like the bees or ants, distinguished from the rest by the size and splendour of their wings, is a circumstance that has not yet been established by any satisfactory evidence; indeed, very strong reasons may be urged against it. The nations of bees and ants, it must be observed, are housed together in one nest or hive, the whole population of which is originally derived from one common mother, and the leaders of the swarms in each are the females. But the armies of locusts, though they herd together, travel together, and feed together, consist of an infinity of separate families, all derived from different mothers, who have laid their eggs in separate cells or houses in the earth; so that there is little or no analogy between the societies of locusts and those of bees and ants; and this pretended sultan is something quite different from the queen-bee or the female ants. It follows, therefore, that as the locusts have no common mother, like the bees, to lead their swarms, there is no one that nature, by a different organization and ampler dimensions, and a more august form, has destined to this high office. The only question remaining is, whether one be elected from the rest by common consent as their leader, or whether their instinct impels them to follow the first that takes flight or alights. This last is the learned Bochart's opinion, and seems much the most reasonable. The absurdity of the other supposition, that an election is made, will appear from such queries as these, at which you may smile.--Who are the electors? Are the myriads of millions all consulted, or is the elective franchise confined to a few? Who holds the courts and takes the votes? Who casts them up and declares the result? When is the election made?--The larvae appear to be as much under government as the perfect insect.--Is the monarch then chosen by his peers when they first leave the egg and emerge from their subterranean caverns? or have larva, pupa, and imago each their separate king? The account given us in Scripture is certainly much the most probable, that the locusts have no king, though they observe as much order and regularity in their movements as if they were under military discipline, and had a ruler over them. Some species of ants, as we learn from the admirable history of them by M. P. Huber, though they go forth by common consent upon their military expeditions, yet the order of their columns keeps perpetually changing; so that those who lead the van at the first setting out, soon fall into the rear, and others take their place: their successors do the same; and such is the constant order of their march. It seems probable, as these columns are extended to a considerable length, that the object of this successive change of leaders is to convey constant intelligence to those in the rear, of what is going forward in the van. Whether any thing like this takes place for the regulation of their motions in the innumerable locust-armies, which are sometimes co-extensive with vast kingdoms; or whether their instinct simply directs them to follow the first that moves or flies, and to keep their measured distance, so that, as the prophet speaks, "one does not thrust another, and they walk every one in his path," must be left to future naturalists to ascertain. And I think that you will join with me in the wish that travellers, who have a taste for Natural History, and some knowledge of insects, would devote a share of attention to the proceedings of these celebrated animals, so that we might have facts instead of fables.

The last order of imperfect associations approaches nearer to perfect societies, and is that of those insects which the social principle urges to unite in some common work for the benefit of the community.

I am, &c.

FOOTNOTES:

The females have red legs, and the males black.

The authors of this work were the witnesses of the magnificent scene here described. It was on the second of September. The first was on the ninth of that month.

De Geer, vi. 338.

ii. 135.

Ibid. xi. 95.

Ibid. 94.

Pallas, ii. 422-6.

Proverbs xxx. 27.

Joel ii. 8.

De Geer, ii. 1029.

Bonnet, ii. 57.

Reaumur, ii. 180.

PERFECT SOCIETIES.

The associations of insects of which my last letter gave you a detail, were of a very imperfect kind, both as to their object and duration: but those which I am now to lay before you exhibit the semblance of a nearer approach, both in their principle and its results, to the societies of man himself. There are two kindred sentiments, that in these last act with most powerful energy--desire and affection.--From the first proceed many wants that cannot be satisfied without the intercourse, aid, and co-operation of others; and by the last we are impelled to seek the good of certain objects, and to delight in their society. Thus self-love combines with philanthropy to produce the social principle, both desire and love alternately urging us to an intercourse with each other; and from these in union originate the multiplication and preservation of the species. These two passions are the master-movers in this business; but there is a third subsidiary to them, which, though it trenches upon the social principle, considered abstractedly, is often a powerful bond of union in separate societies--you will readily perceive that I am speaking of fear;--under the influence of this passion these are drawn closer together, and unite more intimately for defence against some common enemy, and to raise works of munition that may resist his attack.

The main instrument of association is language, and no association can be perfect where there is not a common tongue. The origin of nationality was difference of speech: at Babel, when tongues were divided, nations separated. Language may be understood in a larger sense than to signify inflections of the voice,--it may well include all the means of making yourself understood by another, whether by gestures, sounds, signs, or words: the two first of these kinds may be called natural language, and the two last arbitrary or artificial.

But when we consider the object of these societies, the preservation and multiplication of the species; and the means by which that object is attained, the united labours and co-operation of perhaps millions of individuals, it seems as if they were impelled by passions very similar to those main-springs of human associations, which I have just enumerated. Desire appears to stimulate them--love to allure them--fear to alarm them. They want a habitation to reside in, and food for their subsistence. Does not this look as if desire were the operating cause, which induces them to unite their labours to construct the one and provide the other? Their nests contain a numerous family of helpless brood. Does not love here seem to urge them to that exemplary and fond attention, and those unremitted and indefatigable exertions manifested by the whole community for the benefit of these dear objects? Is it not also evidenced by their general and singular attachment to their females, by their mutual caresses, by their feeding each other, by their apparent sympathy with suffering individuals and endeavours to relieve them, by their readiness to help those that are in difficulty, and finally by their sports and assemblies for relaxation? That fear produces its influence upon them seems no less evident, when we see them, agitated by the approach of enemies, endeavour to remove what is most dear to them beyond their reach, unite their efforts to repel their attacks, and to construct works of defence. They appear to have besides a common language; for they possess the faculty, by significative gestures and sounds, of communicating their wants and ideas to each other.

There are, however, the following great differences between human societies and those of insects. Man is susceptible of individual attachment, which forms the basis of his happiness, and the source of his purest and dearest enjoyments:--whereas the love of insects seems to be a kind of instinctive patriotism that is extended to the whole community, never distinguishing individuals, unless, as in the instance of the female bee, connected with that great object.

Man also, endowed with reason, forms a judgement from circumstances, and by a variety of means can attain the same end. Besides the language of nature, gestures, and exclamations, which the passions produce, he is gifted with the divine faculty of speech, and can express his thoughts by articulate sounds or artificial language.--Not so our social insects. Every species has its peculiar mode of proceeding, to which it adheres as to the law of its nature, never deviating but under the control of imperious circumstances; for in particular instances, as you will see when I come to treat of their instincts, they know how to vary, though not very materially, from the usual mode. But they never depart, like man, from the general system; and, in common with the rest of the animal kingdom, they have no articulate language.

Human associations, under the direction of reason and revelation, are also formed with higher views,--I mean as to government, morals, and religion:--with respect to the last of these, the social insects of course can have nothing to do, except that by their wonderful proceedings they give man an occasion of glorifying his great Creator; but in their instincts, extraordinary as it may seem, they exhibit a semblance of the two former, as will abundantly appear in the course of our correspondence.

I shall not detain you longer by prefatory remarks from the amusing scene to which I am eager to introduce you; but the following observations of M. P. Huber on this subject are so just and striking, that I cannot refrain from copying them.

"The history of insects that live in solitude consists of their generation, their peculiar habits, the metamorphoses they undergo; their manner of life under each successive form; the stratagems for the attack of their enemies, and the skill with which they construct their habitation: but that of insects which form numerous societies, is not confined to some remarkable proceedings, to some peculiar talent: it offers new relations, which arise from common interest; from the equality or superiority of rank; from the part which each member supports in the society;--and all these relations suppose a connexion between the different individuals of which it consists, that can scarcely exist but by the intervention of language: for such may be called every mode of expressing their wishes, their wants, and even their ideas, if that name may be given to the impulses of instinct. It would be difficult to explain in any other way that concurrence of all wills to one end, and that species of harmony which the whole of their institution exhibits."

Before I begin with the history of the societies of white ants, I must notice a remark that has been made applying to societies in general--that numbers are essential to the full development of the instinct of social animals. This has been observed by Bonnet with respect to the beaver; by Reaumur of the hive-bee; and by M. P. Huber of the humble-bee. Amongst hymenopterous social insects, however, the observation seems not universally applicable, but only under particular circumstances; for in incipient societies of ants, humble-bees, and wasps, one female lays the foundations of them at first by herself; and the first brood of neuters that is hatched is very small.

The first establishment of a colony of Termites takes place in the following manner. In the evening, soon after the first tornado, which at the latter end of the dry season proclaims the approach of the ensuing rains, these animals, having attained to their perfect state, in which they are furnished and adorned with two pair of wings, emerge from their clay-built citadels by myriads and myriads to seek their fortune. Borne on these ample wings, and carried by the wind, they fill the air, entering the houses, extinguishing the lights, and even sometimes being driven on board the ships that are not far from the shore. The next morning they are discovered covering the surface of the earth and waters: deprived of the wings which before enabled them to avoid their numerous enemies, and which are only calculated to carry them a few hours, and looking like large maggots; from the most active, industrious, and rapacious, they are now become the most helpless and cowardly beings in nature, and the prey of innumerable enemies, to the smallest of which they make not the least resistance. Insects, especially ants, which are always on the hunt for them, leaving no place unexplored; birds, reptiles, beasts, and even man himself, look upon this event as their harvest, and, as you have been told before, make them their food; so that scarcely a single pair in many millions get into a place of safety, fulfill the first law of nature, and lay the foundation of a new community. At this time they are seen running upon the ground, the male after the female, and sometimes two chasing one, and contending with great eagerness, regardless of the innumerable dangers that surround them, who shall win the prize.

The workers, who are continually prowling about in their covered ways, occasionally meet with one of these pairs, and, being impelled by their instinct, pay them homage, and they are elected as it were to be king and queen, or rather father and mother, of a new colony: all that are not so fortunate, inevitably perish; and, considering the infinite host of their enemies, probably in the course of the following day. The workers, as soon as this election takes place, begin to inclose their new rulers in a small chamber of clay, before described, suited to their size, the entrances to which are only large enough to admit themselves and the neuters, but much too small for the royal pair to pass through;--so that their state of royalty is a state of confinement, and so continues during the remainder of their existence. The impregnation of the female is supposed to take place after this confinement, and she soon begins to furnish the infant colony with new inhabitants. The care of feeding her and her male companion devolves upon the industrious larvae, who supply them both with every thing that they want. As she increases in dimensions, they keep enlarging the cell in which she is detained. When the business of oviposition commences, they take the eggs from the female, and deposit them in the nurseries. Her abdomen now begins gradually to extend, till in process of time it is enlarged to 1500 or 2000 times the size of the rest of her body, and her bulk equals that of 20,000 or 30,000 workers. This part, often more than three inches in length, is now a vast matrix of eggs, which make long circumvolutions through numberless slender serpentine vessels:--it is also remarkable for its peristaltic motion, which, like the undulations of water, produces a perpetual and successive rise and fall over the whole surface of the abdomen, and occasions a constant extrusion of the eggs, amounting sometimes in old females to sixty in a minute, or eighty thousand and upwards in twenty-four hours. As these females live two years in their perfect state, how astonishing must be the number produced in that time!

The royal cell has besides some soldiers in it, a kind of body guard to the royal pair that inhabit it; and the surrounding apartments contain always many both labourers and soldiers in waiting, that they may successively attend upon and defend the common father and mother, on whose safety depend the happiness and even existence of the whole community; and whom these faithful subjects never abandon even in the last distress.

You have before heard of their diligence in building. Does any accident happen to their various structures, or are they dislodged from any of their covered ways, they are still more active and expeditious in repairing. Getting out of sight as soon as possible,--and they run as fast or faster than any insect of their size,--in a single night they will restore a gallery of three or four yards in length. If, attacking the nest, you divide it in halves, leaving the royal chamber, and thus lay open thousands of apartments, all will be shut up with their sheets of clay by the next morning;--nay, even if the whole be demolished, provided the king and the queen be left, every interstice between the ruins, at which either cold or wet can possibly enter, will be covered, and in a year the building will be raised nearly to its pristine size and grandeur.

Besides building and repairing, a great deal of their time is occupied in making necessary alterations in their mansion and its approaches. The royal presence-chamber, as the female increases in size, must be gradually enlarged, the nurseries must be removed to a greater distance, the chambers and exterior of the nest receive daily accessions to provide for a daily increasing population--and the direction of their covered ways must often be varied, when the old stock of provision is exhausted and new discovered.

The collection of provisions for the use of the colony is another employment, which necessarily calls for incessant attention: these to the naked eye appear like raspings of wood;--and they are, as you have seen, great destroyers of timber, whether wrought or unwrought:--but when examined by the microscope, they are found to consist chiefly of gums and the inspissated juices of plants, which, formed into little masses, are stored up in magazines made of clay.

When any one is bold enough to attack their nest and make a breach in its walls, the labourers, who are incapable of fighting, retire within, and give place to another description of its inhabitants, whose office it is to defend the fortress when assailed by enemies:--these, as observed before, are the neuters or soldiers. If the breach be made in a slight part of the building, one of these comes out to reconnoitre; he then retires and gives the alarm. Two or three others next appear, scrambling as fast as they can one after the other;--to these succeed a large body, who rush forth with as much speed as the breach will permit, their numbers continually increasing during the attack. It is not easy to describe the rage and fury by which these diminutive heroes seem actuated. In their haste they frequently miss their hold, and tumble down the sides of their hill: they soon, however, recover themselves, and, being blind, bite every thing they run against. If the attack proceeds, the bustle and agitation increase to a ten-fold degree, and their fury is raised to its highest pitch. Wo to him whose hands or legs they can come at! for they will make their fanged jaws meet at the very first stroke, drawing as much blood as will counterpoise their whole body, and never quitting their hold, even though they are pulled limb from limb. The naked legs of the Negroes expose them frequently to this injury; and the stockings of the European are not sufficient to defend him.

While the labourers are thus employed, almost all the soldiers have retired quite out of sight, except here and there one, who saunters about amongst them, but never assists in the work. One in particular places himself close to the wall which they are building; and turning himself leisurely on all sides, as if to survey the proceedings, appears to act the part of an overseer of the works. Every now and then, at the interval of a minute or two, by lifting up his head and striking with his forceps upon the wall of the nest, he makes a particular noise, which is answered by a loud hiss from all the labourers, and appears to be a signal for dispatch; for, every time it is heard, they may be seen to redouble their pace, and apply to their work with increased diligence. Renew the attack, and this amusing scene will be repeated:--in rush the labourers, all disappearing in a few seconds, and out march the military as numerous and vindictive as before.--When all is once more quiet, the busy labourers reappear, and resume their work, and the soldiers vanish. Repeat the experiment a hundred times, and the same will always be the result;--you will never find, be the peril or emergency ever so great, that one order attempts to fight, or the other to work.

Till the manners of exotic ants are more accurately explored, it would, however, be rash to affirm that no ants have magazines of provisions; for although, during the cold of our winters in this country, they remain in a state of torpidity, and have no need of food, yet in warmer regions, during the rainy seasons, when they are probably confined to their nests, a store of provisions may be necessary for them. Even in northern climates, against wet seasons, they may provide in this way for their sustenance and that of the young brood, which, as Mr. Smeathman observes, are very voracious, and cannot bear to be long deprived of their food; else why do ants carry worms, living insects, and many other such things into their nests? Solomon's lesson to the sluggard has been generally adduced as a strong confirmation of the ancient opinion: it can, however, only relate to the species of a warm climate, the habits of which, as I have just observed, are probably different from those of a cold one;--so that his words, as commonly interpreted, may be perfectly correct and consistent with nature, and yet be not at all applicable to the species that are indigenous to Europe. But I think, if Solomon's words are properly considered, it will be found that this interpretation has been fathered upon them, rather than fairly deduced from them. He does not affirm that the ant which he proposes to his sluggard as an example, laid up in her magazines stores of grain: "Go to the ant thou sluggard, consider her ways and be wise; which, having neither captain, overseer, nor ruler, prepares her bread in the summer, and gathers her food in the harvest." These words may very well be interpreted simply to mean, that the ant, with commendable prudence and foresight, makes use of the proper seasons to collect a supply of provision sufficient for her purposes. There is not a word in them implying that she stores up grain or other provision. She prepares her bread, and gathers her food,--namely, such food as is suited to her,--in summer and harvest,--that is, when it is most plentiful,--and thus shows her wisdom and prudence by using the advantages offered to her. The words thus interpreted, which they may be without any violence, will apply to our European species as well as to those that are not indigenous.

Captain Haverfield, R. N. gave me an account of an extraordinary appearance of ants observed by him in the Medway, in the autumn of 1814, when he was first-lieutenant of the Clorinde--which is confirmed by the following letter addressed by the surgeon of that ship, now Dr. Bromley, to Mr. MacLeay:

"In September 1814, being on the deck of the hulk to the Clorinde, my attention was drawn to the water by the first-lieutenant observing there was something black floating down with the tide. On looking with a glass, I discovered they were insects.--The boat was sent, and brought a bucket full of them on board;--they proved to be a large species of ant, and extended from the upper part of Salt-pan reach out towards the Great Nore, a distance of five or six miles. The column appeared to be in breadth eight or ten feet, and in height about six inches, which I suppose must have been from their resting one upon another." Purchas seems to have witnessed a similar phenomenon on shore. "Other sorts ," says he, "there are many, of which some become winged and fill the air with swarms, which sometimes happens in England. On Bartholomew 1613 I was in the island of Foulness on our Essex shore, where were such clouds of these flying pismires, that we could no where fly from them, but they filled our clothes; yea the floors of some houses where they fell were in a manner covered with a black carpet of creeping ants; which they say drown themselves about that time of the year in the sea."

These ants were winged:--whence, in the first instance here related, this immense column came was not ascertained. From the numbers here agglomerated, one would think that all the ant-hills of the counties of Kent and Surrey could scarcely have furnished a sufficient number of males and females to form it.

When Colonel Sir Augustus Frazer, of the Horse Artillery, was surveying on the 6th of October 1813 the scene of the battle of the Pyrenees from the summit of the mountain called Pena de Aya, or Les Quatre Couronnes, he and his friends were enveloped by a swarm of ants, so numerous as entirely to intercept their view, so that they were glad to remove to another station, in order to get rid of them.

The females that escape from the injury of the elements and their various enemies, become the founders of new colonies, doing all the work, as I have related in a former letter, that is usually done by the neuters. M. P. Huber has found incipient colonies, in which were only a few workers engaged with their mother in the care of a small number of larvae; and M. Perrot, his friend, once discovered a small nest, occupied by a solitary female, who was attending upon four pupae only. Such is the foundation and first establishment of those populous nations of ants with which we every where meet.

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