114 THE SCOLYTID BEETLES. 



Santa Fe, N. Mex. ; Henrys Lake National Forest and Beaver Can- 

 yon, Idaho; Ventura County, Cal., and Vancouver, British Columbia. 

 It is represented in the forest-insect collection of the Bureau of Ento- 

 mology by more than 700 specimens, including all stages and work. 



BIBLIOGRAPHY. 



Hopkins, 18996 (under D. similis), pp. 10, 11, 15, 21, 22, 26; Hopkins, 19016, p. 67: 

 Hopkins, 1903a, p. 60; Hopkins, 1904, p. 19; Hopkins, 1905, pp. 10, 11; Hopkins, 

 1906a, p. 4; Hopkins, 1909, pp. 121-126. 



No. 14. THE EASTERN SPRUCE BEETLE. 



(Dendroctonus piceaperda Hopk. Figs. 70-77.) 



The eastern spruce beetle is a reddish-brown to black barkbeetle, 

 5 to 6 mm. in length, the body sparsely clothed with long hairs, the 

 head broad and convex, the pronotum often darker than the elytra, 

 with the sides distinctly narrowed and constricted toward the head 

 and the punctures of irregular sizes and moderately coarse, the elytra 

 with coarse rugosities between rows of indistinct punctures, and the 

 elytral declivity somewhat flattened, smooth, and shining in the male, 

 more convex, roughened, and less shining in the female. (See fig. 70.) 

 It attacks the red, black, and white spruce from New Brunswick, 

 Canada, southward in the mountains of New York and Pennsylvania, 

 and westward to Michigan. The adult bores through the outer bark 

 to the inner living portion, extends its egg gallery (figs. 71, 73) lon- 

 gitudinally through the inner bark, and grooves the outer layers of 

 wood (fig. 72). From ten to thirty or more eggs are deposited 

 close together in elongate cavities in the sides of the egg gallery. 

 The larvae soon hatch and begin to feed on the bark. At first the 

 larval mines are usually connected, forming a common cavity, 

 but later each larva excavates an independent mine, which it ex- 

 tends in a generally transverse but irregular course from the egg 

 gallery, with the transformation cell at the farther end in the inner 

 bark or between the inner and outer bark; but, like their larval 

 mine, this is usually exposed on the inner surface. The presence of 

 this insect in standing living or dying trees is indicated by reddish 

 boring-dust in the crevices of the bark, by pitch or gum tubes, and 

 by the fading and falling of the leaves, or by the bare reddish ap- 

 pearance of the twigs. It is a very destructive enemy of mature red 

 and white spruce. 



SEASONAL HISTORY. 



(See fig. 75.) 



OVERWINTERING STAGES. 



The winter is passed in the inner bark of trees in which the insect 

 developed the previous summer, as adults and all stages of larvae. 



