LETTER XL. 



INTERNAL ANATOMY AND PHYSIOLOGY 

 OF INSECTS, CONTINUED. 



DIGESTION. 



f 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 

 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- 

 bai 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 a ." 



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 



a Anat. Comp. iy. 120. 



