THE WESTERN PINE-DESTROTING BARKBEETLE. 



19 



Fig. 8. — The western pine-destroying barltbeetle {Dendroctonus brevi- 

 comis): Galleries in the inner bark. (Original.) 



"sorrel tops," and the dead ones, with reddish-brown foliage, are 

 called "red tops," or, if with bare branches or broken tops, are known 

 as '-'black tops" or "broken tops;"° (2) by small masses of resin 

 (pitch tubes, figs. 

 11 and 12, c) in 

 the crevices of the 

 bark of recently 

 attacked living 

 trees, as well as 

 in those of the 

 dying and dead 

 ones; and (3) the 

 presence of the 

 species is deter- 

 mined by remov- 

 ing the bark from 

 the dying and dead trees and finding the characteristic galleries (fig. 

 8 and Pis. II, III). 



It must be remembered, however, that there are many different 

 kinds of insects, some of them closely resembling the destructive 

 species, always found in dying pine trees. Therefore, for the general 

 observer to be positive in the matter, specimens of insects and work 

 should be sent to the Bureau of Entom.ology for authentic identifi- 

 cation. 



DISTRIBUTION. 



The insect is found in southern Idaho throughout, and its range 

 extends to the northern part of the State. It is recorded from Cali- 

 fornia, Oregon, and eastern and western Washington, and, according 

 to Doctor Hopkins, a variety occurs in Arizona and New Mexico and 

 attacks the western yellow pine {Pinus ponderosa) and the sugar pine 

 {Pinus lamhertidna) . 



EXTENT OF DAMAGE AND LOSSES. 



With our present knowledge of the destructive work of this insect, 

 it is evident that a vast amount of timber has been killed by it during 

 the past ten years within the range of its distribation. It is estimated 

 that each year for the past two or three years, from 2 to 5 per cent of 

 the matured standing bull pine timber within the section investigated 

 in the summer of 1905 has died as tne result of its ravages. 



POSSIBILITIES OF PREVENTING LOSSES. 



With our additional knowledge of the life history and habits of the 

 beetle, we are able to suggest practical methods of controlling it and 

 of preventing a large percentage of the losses heretofore caused by its 

 depredations. 



a See Bui. 56, Bur. Ent., U. S. Dept. Agric. The Black Hills Beetle. 



