LETTER XIV.

HABITATIONS OF INSECTS.

In forming an estimate of the civilization and intellectual progress of a newly discovered people, we usually pay attention to their buildings and other proofs of architectural skill. If we find them, like the wretched inhabitants of Van Diemen's Land, without other abodes than natural caverns or miserable penthouses of bark, we at once regard them as the most ignorant and unhumanized of their race. If, like the natives of the South Sea Isles, they have advanced a step further, and enjoy houses formed of timber, thatched with leaves, and furnished with utensils of different kinds, we are inclined to place them considerably higher in the scale. When, as in the case of ancient Mexico, we discover a nation inhabiting towns containing stone houses, regularly disposed into streets, we do not hesitate without other inquiry to decide that it must have been civilized in no ordinary degree. And if it were to chance that some future Park in Africa should stumble upon the ruins of a large city, where, in addition to these proofs of science, every building was constructed on just geometrical and architectural principles; where the materials were so employed as to unite strength with lightness, and a confined site so artfully occupied as to obtain spacious symmetrical apartments, we should

eagerly inquire into the history of the inhabitants, and sigh over the remains of a race whose intellectual advances we should infer with certainty were not inferior to our own.

Were we by the same test to estimate the sagacity of the different classes of animals, we should beyond all doubt assign the highest place to insects, which in the construction of their habitations leave all the rest far behind. The nests of birds, from the rook's rude assemblage of sticks to the pensile dwellings of the tailorbird, wonderful as they doubtless are, are indisputably eclipsed by the structures formed by many insects; and the regular villages of the beaver, by far the most sagacious architect amongst quadrupeds, must yield the palm to a wasp's nest. You will think me here guilty of exaggeration, and that, blinded by my attachment to a favourite pursuit, I am elevating the little objects, which I wish to recommend to your study, to a rank beyond their just claim. So far, however, am I from being conscious of any such prejudice, that I do not hesitate to go further, and assert that the pyramids of Egypt, as the work of man, are not more wonderful for their size and solidity than are the structures built by some insects.

To describe the most remarkable of these is my present object; and that some method may be observed, I shall in this letter describe the habitations of insects living in a state of solitude, and built each by a single architect; and in a subsequent one, those of insects living in societies built by the united labours of many. The former class may be conveniently subdivided into habitations built by the parent insect, not for its own

use, but for the convenience of its future young; and those which are formed by the insect that inhabits them for its own accommodation. To the first I shall now

call your

your attention.

The solitary insects which construct habitations for their future young without any view to their own accommodation, chiefly belong to the order Hymenoptera, and are principally different species of wild bees. Of these the most simple are built by M. succincta, fodiens, and other species of the first family of the genus Melitta, Kirby (Colletes, Latr.). The situation which the parent bee chooses, is either the dry earth of a bank, or the vacuities of stone walls cemented with earth instead of mortar. Having excavated a cylinder about two inches in depth, running usually in a horizontal direction, the bee occupies it with three or four cells about half an inch long, and one-sixth broad, shaped like a thimble, the end of one fitting into the mouth of another. The substance of which these cells are formed is two or three layers of a silky membrane, composed of a kind of glue secreted by the animal, resembling gold-beater's leaf, but much finer, and so thin and transparent that the colour of an included object may be seen through them. As soon as one cell is completed, the bee deposits an egg within, and nearly fills it with a paste composed of pollen and honey; which having done, she proceeds to form another cell, storing it in like manner until the whole is finished, when she carefully stops up the mouth of the orifice with earth, Our countryman Grew seems to have found a series of these nests in a singular situation-the middle of

1

the pith of an old elder-branch-in which they were placed lengthwise one after another with a thin boundary between each.

Cells composed of a similar membranaceous substance, but placed in a different situation, are constructed by Apis manicata, L. This gay insect does not excavate holes for their reception, but places them in the cavities of old trees, or of any other object that suits its purpose. Sir Thomas Cullum discovered the nest of one in the inside of the lock of a gardengate, in which I have also since twice found them. It should seem, however, that such situations would be too cold for the grubs without a coating of some nonconducting substance. The parent bee, therefore, after having constructed the cells, laid an egg in each, and filled them with a store of suitable food, plasters them with a covering of vermiform masses, apparently composed of honey and pollen; and having done this, aware, long before Count Rumford's experiments, what materials conduct heat most slowly, she attacks the woolly leaves of Stachys lanata, Agrostemma coronaria, and similar plants, and with her mandibles industriously scrapes off the wool, which with her fore legs she rolls into a little ball and carries to her nest. This wool she sticks upon the plaster that covers her cells, and thus closely envelops them with a warm coating of down impervious to every change of temperature".

a Grew's Rarities of Gresham Colledge, 154. Kirby Mon. Ap. Angl. i. 131. Melitta. *. a.

b Mon. Ap. Ang. i. 173. Apis **. c. 2. a. From later observations I am inclined to think that these cells may possibly, as in the case of the humble-bee, be in fact formed by the larva previously to becoming a

The bee last described may be said to exercise the trade.of a clothier. Another numerous family would be more properly compared to carpenters, boring with incredible labour out of the solid wood long cylindrical tubes, and dividing them into various cells. Amongst these, one of the most remarkable is the Apis violacea,L. (Xylocopa, Latr.), a large species, a native of Southern Europe, distinguished by beautiful wings of a deep violet colour, and found commonly in gardens, in the upright putrescent espaliers or vine-props of which, and occasionally in the garden seats, doors and windowshutters, she makes her nest. In the beginning of spring, after repeated and careful surveys, she fixes upon a piece of wood suitable for her purpose, and with her strong mandibles begins the process of boring. First proceeding obliquely downwards, she soon points her course in a direction parallel with the sides of the wood, and at length with unwearied exertion forms a cylindrical hole or tunnel not less than twelve or fifteen inches long and half an inch broad. Sometimes, where the diameter will admit of it, three or four of these pipes, nearly parallel with each other, are bored in the same piece. Herculean as this task, which is the labour of several days, appears, it is but a small part of what our industrious bee cheerfully undertakes. As yet she has completed but the shell of the destined habitation of her offspring; each of which, to the number of ten or twelve, will require a separate and dipupa, after having eaten the provision of pollen and honey with which the parent bee had surrounded it. The vermicular shape, however, of the masses with which the cases are surrounded, does not seem easily reconcileable with this supposition, unless they are considered as the

exer ment of the larva.