ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 



Fig. 4. — Ash borer: adult (museum specimen). The female adult, a 

 clear-winged moth, deposits eggs on the bark of a tree. Upon hatching, the 

 young borers penetrate the bark and bore into the wood. 



tain ash. The adult, a moth with transparent rear wings, depos- 

 its eggs on the bark of the tree. The white larva eats through 

 the bark, penetrating the harder wood to the center of some 

 branches. In the fall, when nearly full grown, and almost an inch 

 long, the borer works toward but not completely through the 

 bark. Here it digs a sort of cell in which it passes the winter. 

 Pupation occurs in the spring, and moths emerge in May and 

 June. 



Control Measure U (end of circular). 



Oystershell Scale, Lepidosaphes ulmi (L.), fig. 5. — The oys- 

 tershell scale is inconspicuous, but it can be detected by careful 

 examination of the limbs and branches it infests. Each scale 

 protects itself by a light to dark brown oystershell-shaped cov- 

 ering about one-eighth inch long. It feeds by sucking plant sap 

 through a threadlike beak. Dense populations of this insect 

 cause severe damage to many kinds of trees and shrubs. 



