126 



THE SCOLYTID BEETLES. 



aid, 1887 (under D. rufipennis), pp. 176 and 243; Peck, 1890 (under D. rufipennis), pp. 

 814-815, and 721-722; Harvey, 1898 (underD. rufipennis), p. 176; Howard and Chitten- 

 den, 1898 (under D. rufipennis), p. 98; Weed and Fiske, 1898 (under D. rufipennis), p. 

 69; Hopkins,- 1899a (under D. rufipennis), p. 293; Cary, 1900 (under D. polygraphus 

 rufipennis), pp. 52-54; Hopkins, 1901a, p. 16; Hopkins, 19016, pp. 68-69 ; Hopkins, 

 19026, p. 21; Hopkins, 1902c, p. 22; Hopkins, 19036, pp. 266-270, 281; Hopkins, 1904, 



p. 26; Hopkins, 1905, pp. 10-11; Felt, 

 1905, pp. 6, 7; Felt, 1906, pp. 379-385, 

 782, 796; Hopkins, 1907, pp. 160-161; 

 Hopkins, 1909, pp. 126-130. 



No. 15. THE ENGELMANN 

 SPRUCE BEETLE. 



(Dendroctonus engelmanni Hopk. 

 Figs. 78-82.) 



The Engelmann spruce beetle 

 is a reddish-brown to black 

 barkbeetle, 5 to 7 mm. in 

 length, with body sparsely 

 clothed with long hairs, head 

 broad and convex, prothorax 

 sometimes darker than the ely- 

 tra and with sides of pronotum 

 distinctly narrowed and con- 

 stricted toward the head and 

 the punctures of irregular size 

 and distinctly coarse, the ely- 

 tra with coarse rugosities be- 

 tween rows of indistinct but 

 coarse punctures, and the de- 

 clivity convex and somewhat 

 flattened. It attacks the En- 

 gelmann spruce, and probably 

 other spruces, from central 

 Idaho southward to the moun- 

 tains of southern New Mexico, 

 and the white spruce in the 

 Black Hills of South Dakota. 

 The galleries are similar to 

 those of the eastern spruce 

 beetle. 



Fig. 78. — The Engelmann spruce beetle {Dendroctonus 

 engelmanni) : Egg gallery in living bark. A, Normal; 

 B, boring dust removed; a, entrance; 6, basal sec- 

 tion; c, boring dust packed in gallery; d, subsequent 

 or inner gallery; e, ventilating burrow; /. egg nest, 

 ■with and without eggs; g, freshly hatched larva?; 

 h, pits in roof of gallery, (Author's illustration. ) 



SEASONAL HISTORY 



OVERWINTERING STAGES. 



The broods of this beetle pass the winter in all stages of larvae and 

 as adults in the inner bark of trees attacked by the parent beetles 

 during the preceding summer. 



