LETTER XL. : 
INTERNAL ANATOMY AND PHYSIOLOGY 
OF INSECTS, CONTINUED. 
DIGESTION. 
“THE 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 ca- 
nal 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 larvee of the Scara- 
bei 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?.” 
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 are here, as in the 
other Classes, often an index of a less substantial kind 
4 Anat. Comp. iv. 129. 
