82 NATURAL HISTORY. [CH. IV. 



it can commence its labour of forming its cocoon, 

 before which, however, the body becomes firmer, 

 more glossy, and somewhat transparent towards its 

 head ; it also lessens in size. 



It may not be out of place to mention here from 

 whence the silk proceeds; — The silk is secreted in 

 the form of a fine yellow gum, in two long slender 

 vessels, one on each side of the body. This silky 

 material, when drawn from the orifices beneath the 

 mouth, appears to be one thread, but is, in fact, com- 

 posed of two fibres, which are extracted from the 

 orifices, and brought together by means of two 

 hooks placed in the mouth. 



The worm, having fixed upon some corner that 

 will suit its purpose, commences the labour by spin- 

 ning thin and irregular threads, so as to support its 

 future dwelling ; it then forms upon these a loose 

 structure of an oval shape, which is called floss silk ; 

 in the three following days it forms a firm and con- 

 sistent, yellow ball, the interior of which is smeared 

 with a peculiar gum, so as to shield it against the 

 rain and various changes of temperatures. The 

 filament is not spun in regular concentric circles, 



I 



