or INSECTS IN GENERA!.. 
347 
Some, immediately on leaving the egg, affume a form 
pretty nearly refcmbling that which they poffefs after 
their growth is completed. The whole order of aptera, 
which comprehends all the different kinds of fpiders, 
come under this denomination : The viviparous infe£ts, 
in like mannner, appear at firft, under their moll perfeft 
form. Some kinds, without undergoing all the changes 
of the filk worm, or that of the common butterfly, after 
having grown for a certain period, depofite a covering in 
which their wings were inveloped, and afcend into the 
air. Previous to this change, however, thefe enjoyed 
the power of locomotion by means of their limbs, and in 
thit flate were diftinguiihed by voracity and activity: 
Of this defcription are all the different fpecies of locnfls. 
The flies, wafps, and bees, conftitute another clafs, which, 
after leaving their vermicular form, and after palling in- 
to their chrylalis flate, difplay their limbs and wings with- 
out being capable of ufing them. The laft and mod com- 
plete example of transformation is difplaycd by the clafs 
of moths and butterflies. On leaving the egg, and eveij 
before it, they affume the form of worms, which they 
again change for that of thenympbe, aurelia, orchryfalis: 
and it is not till they have lived a confiderable time un- 
der this form, that they throw off a fecond covering, and 
come forth winged infe&s. 
One of the mod wonderful circumflances in the econo- 
my of infe&s, is the different preparations which they 
make, and the expedients to which they have rceourfe for 
their prefervaticn in their aurelia flate. Many dig a hole in 
the earth, ivhere they remain during the whole period of 
their inactivity. This is the invention of all the coleop- 
terous infcfts, or fuch as have cruflaceous wings. The 
x 3 gnats, 
