156 



THE INSECT WOELD. 



Among caterpillars that make a very slight cocoon, some, as the 

 Catocalas, gather together two or three leaves into a ball, to 

 protect them. Others strengthen their cocoons, 

 and render them opaque by adding earth, or other 

 substances, often obtained from their own bodies. 

 Some, after having spun their cocoon, cast forth 

 through the anus three or four masses of a matter 

 resembling paste, which they apply with their 

 head to the inside of the cocoon, and which, dry- 

 ing quickly, becomes pulverulent. Others employ 

 for the same purpose the hairs with which their 

 bodies are covered. 

 The larva of Acronycta aceris (Fig. 113) is covered with tufts of 



Fig. 111. Cocoon, 

 after Keaumur. 



Fig. 112. Larvae of Catocala fraxini. 



yellow hair. Reaumur made these caterpillars work under his 

 own eye in glass vases. They make the layer which is to form 



Fig. 113. Larva of Acronycta aceris. 



the exterior surface of their shell or cocoon, of pure silk, and when 

 it is thick enough, tear out their hair, now from one place, now 

 from another. But we will leave the illustrious observer to 



