THE GENUS DENDROCTONUS. 
115 
ACTIVITY OP OVERWINTERED BROODS. 
There is some evidence that a few parent adults hibernate in gal- 
leries started the previous fall and that they may begin activity some- 
Fig. 70.— The eastern spruce beetle (Dendroctonus piceaperda): 1, 2, Adult, dorsal and lateral aspects; 
2a, 2b, $ , 9, details of adult; 3, pupa; 3a, lateral aspect of head and prothorax of pupa; h, larva; 
ha, hb, he, details of larva. All greatly enlarged. (Author's illustration.) 
what earlier than the overwintered broods. The overwintered, de- 
veloped adults begin to emerge about the middle of June and con- 
tinue emergence until August, or later, the principal emergence 
taking place during July. They begin to attack the trees and exca- 
vate galleries soon after they emerge, and by the 19th of June begin 
