132 



THE SCOLYTID BEETLES. 



broad, with median dorsal groove and the apex subacutely emar- 

 ginate; labrum prominent, its anterior margin truncate; mandibles 

 opaque toward base, more shining toward apex, with a distinct dorsal 

 impression and oblique ridge near the middle; sternellar lobes of the 

 thoracic segments moderately prominent and with distinct foot calli. 

 t Larval type labeled "Webb 



No. 2." 



The most distinctive charac- 

 ters separating the larva of this 

 species from that of the preced- 

 ing one are the more shining 

 mandibles, with much deeper 

 dorsal impression and more 

 prominent oblique ridge and 

 the much less distinctly ele- 

 vated anterior margin of the 

 epicranium. 



Galleries (fig. 81). The gal- 

 leries of this species are very 

 much the same as those of the 

 preceding one, except that the 

 larval mines are more distinctly 

 contiguous for a greater dis- 

 tance from the egg galleries. 

 Distribution (fig. 82). 

 (Hopk. U. S.) Arizona: Chiri- 

 cahua Mountains. Colorado: 

 Clyde, Boulder, Craig, Fort Col- 

 lins, Glenwood Springs, Gunni- 

 son, Hahn's Peak, Holy Cross 

 National Forest, Meeker, Ou- 

 ray National Forest, Sun Isabel 

 National Forest, Steamboat 

 Springs, White River National 

 Forest. Neiu Mexico: Capi- 

 tan Mountains, Sierra Blanca 

 Mountains, Sacramento Na- 

 tional Forest. South Dakota: 

 Spearfish Canyon, Black Hills. 

 Utah: Ephraim. Wyoming: En- 

 campment. Additional localities from specimens in other collec- 

 tions : (Horn) "H. B." (Northwest Territory, probably in Macken- 

 zie River region) and Alta, Utah. (Wickham) Argentine, Leadville, 

 and Silver Plume, Colo. (Cockerell) Las Vegas, N. Mex. (H. & S.) 

 Calgary, Alberta; Glacier, British Columbia. (Webb) Collins, Idaho. 



FIG. 81.Dendroctonus engelmanni: Egg gallery in liv- 

 ing bark. A, Normal; B, boring dust removed; a, 

 entrance; 6, basal section; c, boring dust packed in 

 gallery; d, subsequent or inner gallery; e, venti- 

 lating burrow;/,egg nest, with and \vithouteggs; g, 

 freshly hatched larvte; h, pits in roof of gallery. 

 (Original.) 



