132 



first two strise strongly inpressed, the strial punctures very small, the 

 1st interspace convex, the 2nd less prominent and flattened apically, the 

 outer part of the declivity strongly convex, the interspaces shining, rather 

 coarsely granulate and setose-punctate uniseriately. The male has the 

 front somewhat wider than the female, plano-convex, densely, coarsely, 

 roughly punctured, with a shallow, transverse, postepistomal impression 

 and a faint median carina in front and behind, sparsely clothed with long 

 hairs; the declivity more pohshed, the punctures minute and the granules 

 small and sparse on the first two interspaces. 



Described from Colorado, and since found to be very abundant in 

 the Canadian Rockies and Selkirks; the Canadian series presents variations 

 but is probably not distinct. Hopkins' ahietis, described from Abies of 

 Montana, is apparently the same species. 



Host trees. — Alpine Fir, Eastern Balsam Fir. 



Distribution. — Colorado; Montana (abietis Hopk.); Rockies and Selkirks 

 of British Columbia, and in northern Alberta. 



Attacks and kills healthy balsam in eastern British Columbia and 

 northern Alberta. 



Dryocoetes pubescens Sw.; Can. Ent., 44: 350, 1912. 



Closely allied to affaber Mannh., from which it is doubtfully distinct 

 in the more slender form and densely, coarsely punctured declivity. It will 

 probably prove to be only a well marked race of affaber. 

 Distribution. — Colorado; habits unknown. 



Dryocoetes affaber Mannh.; Bull. Mosc, 359, 1852 (Bostrichus) . 



The species of this section of Dryocoetes are very closely allied. D. 

 picece Hopk. was separated from affaber through its smaller average size, 

 2-3 mm. to 2-75 mm., and its eastern distribution. Our specimens from 

 the Maritime Provinces and Quebec are constantly small, less than 2-75 

 mm. in length, and rather more coarsely punctured than the western 

 specimens; our specimens from Manitoba are very faintly larger, a long 

 series from Edmonton ranging between 2-5 mm. and 3 mm. in length; 

 seventy-five specimens from south central British Columbia vary between 

 2 • 6 mm. and 3 • 1 mm. ; over two hundred from northern Alberta range 

 between 2-3 mm. and 3-2 mm., with many 2-8 mm., and our typical 

 affaber from the northern coast of British Columbia varies between 2-5 

 and 3 • 2 mm. with an average of nearly 3 mm. Our collection indicates a 

 gradual increase in size towards the north and west but presents no definite 

 specific distinction between the typical affaber and our eastern race which 

 is apparently picece Hopk., left in this paper as doubtfully distinct. (PI. 11, 

 fig. 3). 



Host trees. — Sitka Spruce, all spruces and probably all pines within 

 its range. 



Distribution. — Alaska, throughout British Columbia and western and 

 northern Alberta, eastward through the northern spruce forests; recorded 

 by Hopkins through the Western United States south to Mexico. 



PLATE 31. 



Dendroctonus brevicomis Lee, The Western Pine Bark-beetle; egg-tunnels on the wood surface 

 of Western Yellow Pine; near Princeton, B.C. (Author's illustration). 



