INSECT ENEMIES OF EASTERN FORESTS 523 
FicurE 143.—Pith flecks: A. in river birch, transverse section, caused by 
Agromysa pruinosa; B, in silver maple, tangential section, caused by A. aceris. 
Natural size. 
Pupation takes place about the last of June, the larvae boring small 
holes through the bark at ground level, where they make their exit. 
If they reach ground level before they are ready to pupate, they reverse 
their mines and go upward a short distance, and then again turn 
downward. Pupation takes place in the soil about 14 to 2 inches from 
the point of exit. The species passes the winter in the puparium. 
