176 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



moth species known as the mulberry or Chinese silk-worm. 

 This thoroughly domesticated and industrious species produces 

 each year over $100,000,000 worth of fine silk. It can be 

 reared with perfect success in this country and made to produce 

 large cocoons of an admirable quality of silk, but the cost of 

 the labor necessary to caring for the larvae through their long 



FIG. 83. Silk-worms, larvae of the moth Bombyx mori. (About \ natu- 

 ral size.) 



growing period is so much higher in America than in Italy, or 

 France, or the Orient, that silk cannot be produced here under 

 present conditions to commercial advantage. The method 

 of rearing silk-worms is, briefly, as follows. 



The heavy, creamy white moths take no food, and most of 

 them cannot fly despite their possession of well-developed 

 wings, so degenerate are the flight muscles from generations 



