The larch bark-beetle, Dendroctonus simplex Lec., is a black beetle with reddish elytra, approximately 4.7 mm. in length, with the front convex, the pronotum constricted in front, elytra slightly wider than the pronotum, the striae moderately impressed, the strial punctures small and deep, the elytra sparsely covered with erect hairs, with the pubescence distinct. It is abundant in dying larch throughout the larch areas of Eastern Canada from the Atlantic westward across Manitoba, northern Saskatchewan and northern Alberta.