OF INSECTS. 
185 
cular system, which supplies nutrition, growth, and life, tc 
ail of them together. 
VI. Almost all insects are oviparous. Nature keeps 
her butterflies, moths, and caterpillars, locked up during 
the winter in their egg state; and we have to admire the 
various devices to which, if we may so speak, the same 
nature hath resorted, for the security of the egg. Many 
insects enclose their eggs in a silken web; others cover 
them with a coat of hair torn from their own bodies; some 
glue them together; and others, like the moth of the silk¬ 
worm, glue them to the leaves upon which they are depos¬ 
ited, that they may not be shaken off by the wind, or wash¬ 
ed away by rain: some again make incisions into leaves, 
and hide an egg in each incision; whilst some envelope 
their eggs with a soft substance, which forms the first ali¬ 
ment of the young animal: and some again make a hole in 
the earth, and having stored it with a quantity of proper 
food, deposit their eggs in it. In all which we are to ob¬ 
serve, that the expedient depends, not so much upon the 
address of the animal, as upon the physical resources of 
his constitution. 
The art also with which the young insect is coiled up in 
the egg, presents, where it can be examined, a subject of 
great curiosity. The insect, furnished with all the members 
which it ought to have, is rolled up into a form which 
seems to contract it into the least possible space; by which 
contraction, notwithstanding the smallness of the egg, it has 
room enough in its apartment, and to spare. This folding 
of the limbs appears to me to indicate a special direction, 
for, if it were merely the effect of compression, the col¬ 
location of the parts would be more various than it is. In 
the same species, I believe, it is always the same. 
These observations belong to the whole insect tribe, or 
to a great part of them. Other observations are limited 
to fewer species; but not, perhaps, less important or satis¬ 
factory. 
1. The organization in the abdomen of the silkworm, 
or spider, whereby these insects form their thread, is as 
incontestably mechanical as a wire-drawer’s mill. In the 
body of the silkworm are two bags, remarkable for their 
form, position, and use. [PI. XXXIII. fig. 1.] They wind 
round the intestine; when drawn out, they are ten inches 
in length, though the animal itself be only two. Within 
these bags is collected a glue; and communicating with 
the bags, are two paps or outlets, perforated, like a giater, 
by a number of small holes. The glue or gum, being pass- 
