ABDOMINAL APPENDAGES OF PUP.E. 213 



fig. 48 a dipterqus pupa; the latter stripped from the 

 cocoon-like skin of the larva. The letter H refers to the 



head, T the thorax, A the abdomen, a a the antennae, e e the 

 eyes, m the mouth, p the palpi, w the fore wings, w w the 

 posterior wings, 1 1 1 1 the legs. 



It must, however, be borne in mind, that in these pupae 

 the limbs have not yet acquired their full size, and the abdo- 

 men is not yet reduced to the size which it will possess in 

 the imago state. 



Pupa? are ordinarily of an elongated oval form, the thick- 

 est part being towards the head; the body is generally 

 smooth, but in some instances various spines or hairs are to 

 be observed upon various parts of the body ; and others, espe- 

 cially the chrysalides of butterflies, are angulated. In some 

 aquatic pupae, as in the midges, forming the genus Chirono- 

 mus, the back of the front part of the thorax is furnished 

 with exserted breathing organs. The structure of the ter- 

 minal segment of the body is also variable ; one of the most 

 remarkable variations occurs in some of the butterflies, in 

 which this part is furnished with hooks, for effecting the sus- 

 pension of suspended chrysalides ; and it may here be noticed, 

 that in those species of Hymenoptera, which have the oviposi- 

 tor long and exserted, it is generally curved upon the back of 



