281' STATES OF INSECTS. 



admiration. In both cases, the vitality of the membra- 

 nous or fleshy receptacle secures it from the action of 

 the included fluid.; but how — who shall explain? 



Ordinarily it is the moth that breaks the cocoon ; but 

 in the goat-moth and many Tortrices it is the pupa it- 

 self that performs the work, either wholly or partially. 

 The pupa of the former is for this purpose furnished 

 with sharp points upon the head, capable of effecting 

 this object a . The locust-moth, another species of Cossus 

 (C. JRobinics Peck), whose history has been admirably 

 detailed by Professor Peck, has a different process. " In 

 the silk-moth," says he, " and all others which I have 

 had opportunity to observe, the chrysalis bursts in the 

 cocoon, and the fluid which surrounded the new insect in 

 it escaping at the same time, so weakens or dissolves the 

 fibre and texture of the silk, that the moth is able to ex-« 

 tricate itself, leaving the chrysalis behind it; but this is 

 not the manner in the locust-moth. After remaining- till 

 all its parts are fully grown and it is ready to quit its 

 prison, a certain quantity of exercise is necessary, to 

 break the ligaments which attach the moth to the shell 

 of the chrysalis, and to loosen the folds of the abdomen. 

 In taking this exercise, it can only move the abdomen in 

 various directions : as one side of the rinp-s is moved for- 

 ward, the hooks in the serrated lines above mentioned 

 (the adminicula) take hold of the silk, and prevent their 

 sliding back; the next flexure brings forward the oppo- 

 site side of the rings, which are prevented by the points 

 on that side from slipping back in the same manner, and 

 the chrysalis is forced out of the slightly woven extremity 



a Lyonnet 16. 



