128 



THE SCOLYTID BEETLES. 



cases the insects have first killed the timber, and the fire has then 

 followed (see fig. 81), leaving the charred trunks and logs as apparent 

 proof that the fire alone was responsible. 



In August, 1905, Supervisor A. W. Jensen, of the Manti National 

 Forest, Utah, reported much destructive work by a beetle which 

 proved to be this species. He stated that in some sections 20 per 

 cent was then attacked or killed, including both the Engelmann 

 spruce and the blue spruce. 



In August, 1906, Mr. Harry Gibler reported that all of the matured 

 Engelmann spruce of the White River National Forest, in Colorado, 

 was more or less affected by a beetle which the writer identified as 

 this species. In response to a request for more detailed informa- 



FlG. 79.— Engelmann spruce evidently killed by Engelmann spruce beetle about 1853-6; pitch-marked 

 galleries common on trunk. Pike National Forest, at elevation of about 10,000 feet. (Original.) 



tion, Mr. Gibler, in a letter dated November 13, 1906, wrote as 

 follows : 



There is no portion o£ the reserve on which they are especially active, but are more 

 or less over the entire area. In some places as much as 90 per cent of the mature 

 timber is already dead and in some localities as little as 2 per cent seems to be affected, 

 and in this connection I would state that so far the oldest trees, and that which is 

 classed as strictly mature timber, have been affected. 



In the Twentieth Annual Report of the United States Geological 

 Survey, p. 137, Mr. G. B. Sudworth states: 



There is a considerable quantity of dead standing spruce mingled with the green 

 timber. It extends in an interrupted irregular narrow belt from the region of Deep 

 Lake and Carbonate westward to the headwaters of East Elk Creek. The dead tim- 



