134 



THE SCOLYTID BEETLES, 



I 



pressed; punctures of pronotum distinctly irregular; posterior half 

 of proepisternal area not punctured; punctures of pronotum and 

 elytra moderately coarse; elytral strise scarcely impressed except in 

 dorsal area; interspaces scarcely coarser and but faintly rugose, 

 except toward base and vertex. Secondary sexual characters : Elytral 

 declivity convex ; striae faintly impressed, with punctures moderately 

 distinct; interspaces slightly convex, with distinct row of granules. 



Type labeled ''Type No. 7453 U.S.N.M.," name label, ''Hopk. 

 1/22/08, U.S.N.M. 22, Alaska, 9 , U.S.N.M. Ace. 25431." 



Male type: Length 6 mm., elytra red; thorax, head, and abdomen 

 much darker; other characters the same as in female, except elytral 

 declivity, which is shining, the striae and strial punctures obscure; 



Fig. 83. — Dendroctonus borealis: Distribution map. (Original.) 



interspaces flat, shining, and 1 and 2 without granules except toward 

 vertex. 



Male type labeled "type of drawing," " $ type," name label, 

 "Hopk. 1/22/08, Picea canadensis, Eagle, Alaska, W. H. Osgood, 

 collector, $ , Hopk. U. S. 1170a." 



Variations. — There is scarcely any variation in the four specimens 

 in the collections, but the color varies from nearly black in the type 

 to the head, thorax, and abdomen dark, and the elj^ra red in the other 

 specimens. 



Distinguishing characters. — The short, stouter form, short and broad 

 pronotum, with the punctures more uniform in size, the punctures of 

 the dorsal striae of the elytra finer and less distinct, serves to distin- 

 guish this species from all of the allied forms. It appears to be more 

 closely allied to D. ohesus, but is distinguished from it by its shorter 

 pronotum and elytra, and the other characters mentioned. 



