Tech. Series 17, Part I, Bureau of Entomology, U. S. Dept, of Agriculture. 



Plate V. 



Dendroctonus Adults. 



Pig. 12.— ii. simplex. Fig. VS.— J), pseudotsugx. Fig. 14.— D. piceapenla. Fig. Hi.— 7>. borealis. 



(Original.) 



