LETTER XL. 
INTERNAL ANATOMY AND PHYSIOLOGY 
OF INSECTS, CONTINUED. 
DIGESTION. 
1 HE immense Class of insects," says the immortal 
Cuvier, " in the structure of its alimentary canal exhibits 
as many variations as those of all the vertebrate animals 
together : there are not only the differences that strike 
us in going from family to family and from species to 
species; but one and the same individual has often a 
canal quite different, according as we examine it in its 
larva or imago state ; and all these variations have rela- 
tions very exact, often easily estimable, with the tempo- 
rary or constant mode of life of the animals in which it 
is observable. Thus the voracious larvae of the Scara- 
b<z'i and butterflies have intestines ten times as large as 
the winged and sober insects — if I may use such an ex- 
pression — to which they give birth 3 ." 
In the natural families of these creatures, the same 
analogy takes place with respect to this part that is ob- 
servable in the rest of the Animal Kingdom ; the length 
and complication of the intestines arc here, as in the 
■ Anat. Comp. 5 v. 129. 
