280 INSECTS AFFECTING SHADE TREES 



dark, oblique line, running across from a little before the apex 

 parallel with the outer margin. 



Injury. The larva feeds on the foliage of oaks and other trees. 

 It is occasionally found upon raspberry and blackberry. 



Control. Arsenical sprays should be effective where prac- 

 ticable. 



The Rustic Borer. Broad, irregular, shallow galleries in the 

 inner bark and outer sapwood of oak, hickory, and some other 



FIG. 284. Gall on spruce caused by the pine chermes (C. pinif olios). Spruce is the alternate 

 host of this insect. (O'Kane, N. H. Circular.) 



trees are frequently caused by this borer (Xylotrechus colonus 

 Fab.). It may attack a tree in perfect health and entirely girdle 

 the same in a few years. The adult beetle is blackish, variegated 

 with yellowish or slatish-white markings. The length is about 

 one-half inch. 



Jumping Seed Galls. One sometimes finds below oak trees 

 large numbers of small, round galls previously attached to the 

 under side of the leaves. These galls contain larva which have 



