180 
OF INSECTS. 
founded on the condition of the offspring. In quadrupeds, 
the young animal draws its nutriment from the body of the 
dam. The male parent neither does, nor can contribute 
any part to its sustentation. In the winged race, the 
young bird is supplied by an importation of food, to procure 
and bring home which, in a sufficient quantity for the de¬ 
mand of a numerous brood, requires the industry of both 
parents. In this difference, we see a reason for the vagrant 
instinct of the quadruped, and for the faithful love of the 
feathered mate. 
CHAPTER XIX. 
OF INSECTS. 
We are not writing a system of natural history; there¬ 
fore we have not attended to the classes into which the 
subjects of that science are distributed. What we had to 
observe concerning different species of animals, fell easily, 
for the most part, within the divisions which the course of 
our argument led us to adopt. There remain, however, 
some remarks upon the insect tribe, which could not prop¬ 
erly be introduced under any of these heads; and which 
therefore, we have collected into a chapter by themselves. 
The structure, and the use of the parts of insects, are 
less understood than that of quadrupeds and birds, not only 
by reason of their minuteness, or the minuteness of their 
f >arts (for that minuteness we can in some measure fol- 
ow with glasses,) but also by reason of the remoteness of 
their manners and modes of life from those of larger ani¬ 
mals. For instance: insects, under all their varieties of 
form, are endowed with antennce, [PI. XXXII. fig. 2, 3.] 
which is the name given to those long feelers that rise 
from each side of the head; but to what common use or 
want of the insect kind, a provision so universal is subser¬ 
vient, has not yet been ascertained: and it has not been 
ascertained, because it admits not of a clear, or very pro¬ 
bable comparison, with any organs which we possess our¬ 
selves, or with the organs of animals which resemble our¬ 
selves in their functions and faculties, or with which we are 
better acquainted than we are with insects. We want a 
ground of analogy. This difficulty stands in our way as to 
some particulars in the insect constitution, which we might 
wish to be acquainted with. Nevertheless, there are many 
