28 UTILIZATION OF MINUTE LIFE. 



The Arindy silkworm (Bombyx Cynthia), dis- 

 covered in Bengal, feeds upon the castor-oil plant 

 (Ricinus communis] . This curious plant, which in In- 

 dia and Africa is a large tree, becomes in our climate 

 a small herbaceous annual. The silk produced by 

 B. Cynthia is remarkably soft and glossy ; it cannot 

 be wound off the cocoon, and is therefore woven 

 into a kind of coarse white cloth of a loose texture, 

 used for clothing, and for packing expensive fabrics. 

 Its durability is so great that a man's lifetime is 

 insufficient to wear out a garment made of it. 



M. Guerin Menneville, who has experimented 

 with this silkworm, informs us that the transfor- 

 mation of its chrysalis into a moth may be arti- 

 ficially suspended for a period of seven months. 

 The chrysalis of our common silkworm may be 

 kept in this state for a period of two years if the 

 temperature be cooL If the latter rises from 15 to 

 18 Cent., the moth comes forth in eighteen or 

 twenty days ; but it is a general rule with insects 

 that the time they remain in the chrysalis state 

 depends upon the temperature. 



The way in which many insects resist cold is 

 truly wonderful. Many larvae and chrysalids may be 

 frozen until they become as brittle as glass, and 

 after having remained for some time in this state, 

 they revive by the application of warmth. Spal- 

 lanzani once exposed the eggs of the silkworm to 



