100 THE STORY-BOOK OF SCIENCE 



this number belong the caterpillars of the cabbage 

 butterfly and the swallow tail. But especially in the 

 making of the silk cell called cocoon is the highest 

 skill of the larvae shown. 



"An ashy white 

 caterpillar, the 

 size of the little 

 finger, is raised in 

 large numbers for 

 its cocoon, with 

 which silk stuffs 

 are made. It is 

 called the silk- 

 worm. In very 

 clean rooms are 

 placed reed 



Silk Worm screens, on which 



Eggs, worm, cocoon, and butterfly , , 



they put mulberry 



leaves, and the young caterpillars come from eggs 

 hatched in the house. The mulberry is a large 

 tree cultivated on purpose to nourish these cater- 

 pillars; it has no value except for its leaves, 

 the sole food of silkworms. Large tracts are de- 

 voted to its cultivation, so precious is the handi- 

 work of the worm. The caterpillars eat the ra- 

 tion of leaves that is frequently renewed on the 

 screens, and from time to time change their skin, ac- 

 cording to their rate of growth. Their appetite 

 is such that the clicking of their jaws is like the 

 noise of a shower falling during a calm on the foli- 

 age of the trees. It is true that the room contains 

 thousands and thousands of worms. The caterpil- 



