208 STATES OF INSECTS. 



thread girthed round their middle. In both cases it 

 should be observed, that the suspension of the pupa is 

 the object in view ; but as the process is the work of the 

 larva, this seems the proper place for explaining it. To 

 begin with the^/zrs^ case. 



You are aware that all lepidopterous larvae have the 

 faculty of spinning silk threads from their mouths, and 

 it will readily occur to you that it is by means of these 

 threads that they suspend themselves. But how ? How 

 is a caterpillar to hang itself by the tail to threads spun 

 from the mouth ? Even suppose this difficulty overcome, 

 others still greater remain. Suppose the caterpillar to 

 be suspended by its tail, — this is but a preparatory ope- 

 ration, — what is required is, that the pupa shall hang in 

 the same position : now when you take into consideration 

 that it is incased within the skin of the larva, and without 

 feet or other external organs; that it has to extricate it- 

 self from this skin ; to hang itself in its place, and to de- 

 tach the skin from the threads which hold it — this will 

 appear no trifling task. Indeed at first view it seems 

 impossible. Country-fellows for a prize sometimes amuse 

 the assembled inhabitants of a village by running races 

 in sacks : take one of the most active and adroit of these, 

 bind him hand and foot, suspend him by the bottom of 

 his sack with his head downwards, to the branch of a 

 lofty tree ; make an opening in one side of the sack, and 

 set him to extricate himself from it, to detach it from 

 its hold, and suspend himself by his feet in its place. 

 Though endowed with the suppleness of an Indian jug- 

 gler, and promised his sack full of gold for a reward, you 

 would set him an absolute impossibility : yet this is what 



