CH. XVII.] CHRYSALIS. 289 



by means of hooks with which that part of its body 

 is furnished. 



To withdraw the tail from the withered case ; to 

 climb up that case, and hook its body to the silken 

 cone, is an operation so delicate and hazardous as 

 to excite the greatest wonder, that an insect which 

 executes it only once during the whole term of its 

 existence, should be found capable of executing it 

 so well. " Assuredly," says Reaumur, " it must 

 have been taught to perforin its task by some great 

 master." 



But the chrysalis does not seem to be content with 

 merely withdrawing itself from its ancient hide : it 

 will not suffer it to remain suspended in its own 

 neighbourhood. In order to rid itself of the annoy- 

 ance of the offensive slough, it bends a section of 

 the lower part of its body into the form of the letter 

 S, and then gives the whole a jerk, which causes 



both its own body and the attached slough to spin 

 round eighteen or twenty times on their axis. As 

 the slough and chrysalis must necessarily go round 

 together, and as the slough is farther than the chry- 

 salis from the centre of gyration, it is evident that 

 the attaching hooks and threads of the slough must 

 suffer a greater strain than those of the chrysalis : 

 consequently the former give way first. This is no 

 sooner perceived by the chrysalis, than it resumes 

 Bb 



