INTRODUCTION. 79 



power of a creature unprovided with arms or legs, 

 it seizes on a portion of the skin between two seg- 

 ments, holding it as with a pair of pincers, and thus 

 supports itself till it withdraw the tail from its 

 sheath. It then elongates the rings of its tail as 

 much as possible, and seizes a higher portion of the 

 skin, repeating the same manoeuvre till the extremity- 

 touch the hillock of silk, to which it immediately ad- 

 heres by means of a number of hooks with which it 

 is provided for the purpose. " These operations of 

 withdrawing the tail from its case," says Reaumur, 

 to whom we have been chiefly indebted for the pre- 

 ceding account, " climbing up the skin, and finally 

 attaching the extremity to the silken web, are very 

 delicate and perilous manoeuvres. It is impossible 

 not to wonder, that an insect which executes them 

 but once in its life, should execute them so well. 

 We must necessarily conclude that it has been in- 

 structed by a Great Master ; for he who has ren- 

 dered it necessary for the insect to undergo this 

 change, has likewise given it all the requisite means 

 for accomplishing it in safety." * In order to get 

 quit of the slough, which is still suspended by its 

 side, the chrysalis curves its tail in such a manner as 

 partly to embrace it, and then, by whirling rapidly 

 round, sometimes not fewer than twenty times, and 

 jerking suddenly against it, it generally succeeds in 

 disengaging it from its fastenings, and throws it to 

 the ground. 



* Reaumur, voL i. p. 423, 424. 



