THE GENUS DENDH<)(T<>NUS. 117 



half bearing long hairs, except in D. terebrans and badly nibbed speci- 

 mens. 



Pupa. Vertex of head faintly impressed, flat or convex, and with 

 two small widely separated frontal granules toward vertex. 



Larva. Abdominal tergites 8 and 9 with dorsal plates except in 

 simplex and pseuUoisugx, and 8 without plate in micans. 



(rdlleries. Egg galleries longitudinal, straight to slightly winding: 

 eggs in groups or masses; larval mines and pupal cells exposed in 

 inner bark. 



SUBDIVISION ( 1 . 

 (Species Nos. 12 to 21, inclusive.) 



The distinctive characters common to the species of this third sub- 

 division are: 



Adults. Front usually with posterior impression, pronotum with 

 large and small punctures intermixed. Pronotum with long hairs on 

 dorsal and lateral areas. 



Sexes. Female: Interspaces of elytral declivity more roughened 

 and the striae more distinctly impressed. Male: The reverse. 



Pupa. Vertex of head flattened or faintly impressed: apices of 

 front and middle femora smooth; abdominal tergites with moderately 

 prominent pleural and dorsal spines. 



Larva. Abdominal tergites 8 and 9 without dorsal plato in simplex 

 and pseudotsugoR and with unarmed dorsal plate in the remaining 

 species. 



Galleries. Egg galleries slightly winding to straight; eggs in 

 groups, but larval mines separated from the beginning, or beyond the 

 middle, except in D. micans. 



12. Dendroctonus simplex Le Conte. 



(PI. V, fig. 12.) 



Adult. Typical female: Length, 3.9 mm., dark reddish-brown. 

 Head with front distinctly convex, with faint posterior impression. 

 Pronotum with distinctly coarse and fine punctures intermixed; ely- 

 tral declivity with striae deeply impressed; epistomal process narrow, 

 flat, the sides nearly parallel, apex not extending beyond the anterior 

 frontal margin; elytral rugosities moderately coarse, becoming finer 

 on the lateral areas, sparse, coarser, and more acute on the dorsal 

 area and vertex; striae toward suture impressed, not impressed on 

 lateral area; strial punctures coarse and distinct. Pronotum with 

 moderately long reclining hairs on lateral area. Secondary sexual 

 characters: Elytral declivity with interspaces more rugose and the 

 striae more distinctly impressed. 



. Typical female labeled, name label, "Hopk. 1/22/08, IT. S. 41, 9 , 

 Grand Ledge, Mich., 21.4" ( = April 21). 



Typical male: Length, 3.8 mm.; elytra more shining, less rugose; 

 declivity shining, interspaces convex and smooth, with fine, distinct 



