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, cf , <?, details of adult; 8, 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 



