THE SPRUCE INVESTIGATION. 251 



by cutting the dead and dying, as well as the living timber in 

 the infested area, and converting it into pulp wood and saw 

 logs as soon as possible after the trouble commences. This 

 would leave a supply of logs and stumps to attract them away 

 from the living timber. 



Natural Enemies. As was determined in 1890 and men- 

 tioned in Bulletin 17, this beetle has numerous insect enemies, 

 which, as was then predicted, are preventing its increase beyond 

 a normal limit, and the same conditions which favor the breed- 

 ing of the beetle, favor the breeding and multiplication of its 

 insect and other enemies. 



The Imported Enemy of Bark Beetles. Large numbers of 

 the European bark beetle destroyer were placed, under the most 

 favorable conditions, in different sections of the spruce forests, 

 and while very few, if any, have been seen since, there is no 

 reason why they should not become established and multiply 

 where there is such an abundance of its natural prey in this 

 common bark beetle. 



LE CONTE'S SPRUCE BARK BEETLE. 1 



This bark beetle is about the same length as the destructive 

 spruce bark beetle, but is easily distinguished from this species 

 by its slender form, rust red color, and the long slender hairs 

 with which its body is thinly clothed. Its habits are quite 

 similar to that of the former species, with which it is usually 

 associated; but does not appear capable of attacking and ex- 

 cavating its egg galleries in living, sappy bark. I have, how- 

 ever, found it mining in the bark of logs which had only been 

 felled a short time, but never in the healthy bark of living 

 trees. In 1890, 1 found it to be quite as common as the former 

 species, as many as twenty-five examples being counted in one 

 square inch of bark, and it was at first thought to be quite as 

 much to blame for the trouble then under investigation. Subse- 

 quent observations indicate that while it might be a powerful ally 

 to the destructive species, it would be dependent upon previous 

 injuries and weakened vitality of the trees to enable it to gain 



1 Dryocoetes granicollis Lee. 



