COCOONS OF LARV.E. 199 



can select of a purely silken cocoon, is that of 

 those 



" spinning worms 



That in their green shops weave the smooth-haired silk." 



This beautiful and valuable cocoon, when ex- 

 amined externally, appears to be formed in two 

 different ways ; for the outer covering is loose and 

 open, while the inner one is compact and close, 

 and so in truth it is, although both coverings are 

 formed of a single thread. The outer has been 



Cocoon of Silk -worm. 



called the scaffolding, by means of which the inner 

 and more solid covering is constructed. The larva 

 stationing itself between two leaves, or in any 

 other suitable spot, fastens its thread to one of 

 the adjoining surfaces, and then proceeds to draw 

 out the fibre and fasten it in various positions 



