92 



THE SCOLYTID BEETLES. 



The broods from eggs deposited by the overwintered parent adults 

 may develop to adults in August and September, but evidently remain 

 in the bark until the next season of activity. 



Fig. 52.— The Black Hills beetle: Egg galleries and larval mines. Slightly reduced. ( Author's 



illustration.) 



GENERATION. 



The overwintered broods of young adults begin to attack the 

 trees, excavate galleries, and deposit eggs toward the last of July; 

 the principal attack is during August, but continues during Sep- 

 tember and until October, or possibly later. The eggs hatch and 

 the larvae begin to feed about the first of August. The principal 



