NO. 10 MORPHOLOGY OF GNATHOTRICHUS SCIIEDL I3 



A considerable amount of injury is caused by these pine hole borers, and they 

 are likely to become mo^e numerous in the future, as cutting becomes more 

 extensive. They breed in all dying trunks, and recently cut logs and 

 stumps; never in dead and dry wood, and seldom, perhaps never, in 

 perfectly healthy trees. The timber-beetles are particularly injurious in 

 the west to fire injured timber. As a control measure it is suggested to 

 pile the logs in a way that they may dry out quickly or when possible 

 to place them in water. 



I918. SWAINE, J. M.(49). 



No new data concerning the description and biology. Host trees : 

 Western hemlock, Douglas fir, western yellow pine. Distribution : 

 Generally distributed through southern British Columbia and 

 southward. 



1922. Hopping, R.(5i). 

 Hopping gives for Gn. retiisiis Lee. the following Host trees : Pinus 

 ponderosa Laws, Pinus lambertiana Dougl., Pinus jcffreyi Oreg. 

 Com., Pinus contorta London, Pseudotsuga taxifolia Britt., and 

 Tsuga mertensiana Bong. 



D. GNATHOTRICHUS SULCATUS LEG 



1868. Leconte, L. J. (2). 



Original description: 



Cryphahis sulcatus. Form, size and sculpture precisely the same as in 

 C. rctusiis, except that the front is divergently aciculate, and the occiput 

 is sparsely punctured ; the elytra are similarly punctulate in rows, but the 

 general surface is more distinctly and densely rugose ; the retuse elevation 

 of the posterior declivity of the elytra is but slightly prominent, and not 

 denticulate ; the hairs behind the middle of the elytra are less numerous. 

 Long. 3.5 mm. 



One specimen from the coast region of middle California was given me by 

 Doctor Horn. The color is paler than that of the three specimens of 

 C. retusus now before me, being yellowish-brown, with the base of the 

 thorax and the sides and tip of the elytra darker. Probably more mature 

 specimens would be darker; it is perhaps the female of the preceding, but 

 having failed to find any sexual characters in C. matcriarius, I am not 

 warranted at present in so regarding it. 



1876. Leconte, J. L., and Horn, H. G.(9). 

 Pityophthorus sulcatus Lee. See under retusus Lcc. 



1878. ElCHHOFF, W.(ii). 

 Quotes Leconte's description. 



1904. Hopkins, A. D. (31). 



Western hemlock wood stainer. Gnalliotrichiis sulcatus Lee. Excavates 

 numerous branching galleries from a central burrow, the broods living in 

 closely joined side chambers; in the sap-wood and heart- wood of western 

 hemlock, Douglas spruce, giant arbor vitae, and fir. California to northern 

 Washington; common in hemlock. 



