CHAPTEE Y. 



INTERNAL ORGANS. 



WE have now discussed the salient points of 

 the external structure of caterpillars, chrysalids, 

 and butterflies. We shall not consider their in- 

 ternal organs at such length, partly because they 

 cannot in themselves possess so great a general 

 interest, and also because they have not yet been 

 sufficiently studied to enable one to present a de- 

 tailed and impartial review. After a short survey 

 in this chapter of their peculiarities in the cater- 

 pillar, we shall turn at once to their appearance 

 in the butterfly, and trace one by one the steps 

 by which the changes are effected. 



In considering the external crust of the animal 

 and its appendages, we have been able by its 

 very organization to examine each part separately 

 without confusion ; and even to recur readily to 

 its characteristics when we afterward wished to 

 follow its development ; for, by the division of 

 the body into distinct regions, and of the regions 

 into separate rings, each bearing its special ap- 

 pendages, the mind could readily locate these and 

 recall them when necessary. When, however, 

 we come to the internal parts, the case is gener- 



