156 THE INSECT WORLD. 
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 
eee for the same purpose the hairs with which their 
after Réaumur. bodies are covered. 
The larva of Acronycta aceris (Fig. 113) is covered with tufts of 


Fig. 112.—Larve of Catocala fraxini. 
yellow hair. .Réaumur made these caterpillars work under his 
own eye in glass vases. They make the layer which is to form 

LOS 
Fig. 113.—Larve 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 relate 
