THE GENUS DENDROCTONUS. 



103 



METHODS OF CONTROL. 



From what is known of the life history and habits it is evident that 

 practically the same methods recommended for species 9 and 10 may 

 be adopted for the successful control of this species. 



BASIS OF INFORMATION. 



Information on this species is based on investigations by Mr. H. E. 

 Burke in July and August, 1906, along the rims of Little Yosemite 

 and Yosemite, California, and by Mr. V. S. Barber, at Sterling and 

 Chester, CaL, in 1907. Additional localities through correspondence 

 are Nevada City, Tallac, Pinogrande, and San Bernardino, CaL 



This species is closely related to the 

 mountain pine and Black Hills beetles, 

 but is quite easily distinguished from 

 them by the slightly more elongate, shin- 

 ing, and finely punctured prothorax. : -r 



BIBLIOGRAPHY. 



Hopkins, 1909, pp. 114-116. 



No. 12. THE EASTERN LARCH BEETLE. 



(Dendroctonus simplex Lee. Figs. 62-64.) 



The eastern larch beetle is a stout, 

 reddish to reddish-brown, cylindrical 

 barkbeetle, 3.5 to 5 mm. in length, with 

 broad, convex head, the prothorax short 

 and strongly narrowed and constricted 

 toward the head, the elytra with coarse 

 rugosities between rows of indistinct 

 punctures, the declivity convex and 

 rather deeply grooved, the spaces be- 

 tween rather convex, and the body sparsely clothed with rather long 

 hairs. (See fig. 62.) It attacks injured, dying, felled, and living 

 eastern larch, from New Brunswick, Canada, westward to northern 

 Michigan, and probably to the western and northern limit of this 

 tree, and south in the higher Alleghenies to northeastern West 

 Virginia and western Maryland. It excavates long, slightly wind- 

 ing egg galleries in the inner bark (fig. 63) and grooves the sur- 

 face of the wood. The eggs are placed in alternate groups of 

 three to six, or more, along the sides of the galleries. The short 

 and broad, or sometimes long larval mines extend at right or oblique 

 angles, and are exposed in the inner bark. The stout, whitish, grub- 

 like larvae transform in separate cells at the ends of the burrows in 



Fig. 62.— The eastern larch beetle (Den- 

 droctonus simplex): Adult. Greatly 

 enlarged. (Author's illustration.) 



