THE GENUS DENDROCTONUS. 



133 



punctured with irregular large and small punctures, the elytra with 

 moderately coarse rugosities between moderately distinct rows of 

 punctures, and the declivity not strongly convex and nearly smooth, 

 shining in the male, more dull and roughened in the female. The 

 entire body is sparsely clothed with long hairs. (See fig. 85.) It 

 attacks the living bark on the trunks of living, dying, and newly 

 felled trees, stumps, and large branches of Sitka spruce, from New- 

 port, Oregon, northward along the coast to Alaska, probably following 

 the distribution of the tree in which it lives. The general character 

 of attack and of egg and larval mines is practically the same as de- 

 scribed under D. piceaperda, except that the larval mines are perhaps 

 more generally connected toward the egg gallery and that the pupal 

 cases are sometimes grooved in the wood, while others are concealed 

 in the outer portion of the inner bark. 



Fig. 84.— The Alaska spruce beetle: Distribution map. (Author's illustration.) 

 SEASONAL HISTORY. 



OVERWINTERING STAGES. 



The winter is passed principally as adults and matured larvae 

 in the inner bark on trees, logs, and stumps where they developed 

 the preceding summer. 



ACTIVITY OF OVERWINTERED BROODS. 



Activity of the overwintered broods begins in April. The adults 

 begin to emerge about the middle of April, and continue to come out 

 as the broods of overwintered larvae develop, probably until the 1st 

 of July, but the principal period of emergence is during May and 

 June. 



