We are not writing a fyftem of natural hiftory; therefore, we have not attended to the claffes, into which the fubjects of that fcience are diftributed. What we had to obferve concerning different fpecies of animals, fell eafily, for the moft part, within the divifions, which the courfe of our argument led us to adopt. There remain, however, fome remarks upon the infect tribe, which could not properly be introduced under any of thefe heads; and which therefore we have collected into a chapter by themfelves.

The ftructure, and the ufe of the parts, of infects, are lefs underftood than that of quadrupeds and birds, not only by reafon of their minutenefs, or the minutenefs of their parts, (for that minutenefs we can, in fome meafure, follow with glaffes) but alfo, by reafon of the remotenefs of their manners and modes of life from thofe of larger animals. For inftance, Infects, under all their varieties of form, are endowed with antennæ, which is the name given to thofe long feelers that rife from each fide of the head; but to what common ufe or want of the infect kind, a provifion fo univerfal is fubfervient, has not yet been afcertained: and it has not been afcertained, becaufe it admits not of a clear, or very probable, comparifon, with any organs which we poffefs ourfelves, or with the organs of animals which refemable ourfelves in their functions and faculties, or with which we are better acquainted than we are with infects.