THE SILK-WORM. 307 



Apparatus for spinning the silk. 



attained its full growth, and is somewhat more 

 than an inch in length, and two lines in thick- 

 ness. It then feeds, during five days, with a 

 most voracious appetite, after which it refuses 

 food, becomes transparent, with a tinge of yel- 

 low, and leaves its silky traces on the leaves 

 that it passes over. These signs denote that it 

 is ready to begin its coccoon, in which it is 

 to undergo its change into a chrysalis. The 

 animals are then furnished with little bushes 

 of heath or broom stuck upright between the 

 shelves : they climb up the twigs, where, after a 

 little while, they begin the foundation of their 

 lodge, and are five days in spinning the coccoon; 

 they generally remain in this state about forty- 

 seven days. The animal now forms for its retreat 

 a cone or ball of silk, spun from two longish bags 

 that lie above the intestines, and which are filled 

 with a gummy fluid of a marigold colour. The 

 apparatus with which it is furnished for spinning 

 the silky threads that principally compose this 

 bag resembles, in some measure, a wire-drawer's 

 machine, in which gold or silver threads are 

 drawn to any degree of fineness; and through 

 this the animal draws its thread with great assi- 

 duity. As every thread proceeds from two gum- 

 bags, it is probable that each supplies its own ; 

 which, however, are united as they proceed from 

 the animal's body. If the thread be examined 

 with a microscope, it will be found flattened on 

 one side, and grooved along its whole length. 



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