262 



INSECTS AFFECTING SHADE TREES 



263) are subject to the attacks of these small flies (Fig. 264). 

 Imperfect galls containing maggots are formed. 



The only remedy suggested is the picking off of affected leaves 

 before the larvae become adult; destroy the galls containing the 

 insects. 



The Bronze Birch Borer (Agrilus anxius Gory). This borer 

 is one of the most injurious and destructive of enemies to shade 



FIG. 262. Insect-made galls on box elder. (Ruggles.) 



trees. The adult beetle is bronze-green or varies in color; it is 

 about one-half of an inch long. Posteriorly there is a notch where 

 the ends of the wing-covers come together. The larvse are small, 

 flattened, footless grubs, creamy white in color, three-fourths of 

 an inch long. The mouth parts are dark, and the small head may 

 be partly drawn into the first segment of the body. 



Life History. Hatching in June or July from eggs laid in 

 crevices in the rougher parts of the bark, the grubs bore through 

 the bark and at once begin to mine the sapwood (Fig. 265). The 



