THE GENUS DENDROCTONUS. 81 



D. simplex Lee., D. frontalis Zimm., eliminating Carphoborus bifurcus Eichh. Eich- 

 lioff. 1881, pp. 125, brief revision, including D. micans (Kug.). Le Conte and Horn, 

 1883, p. 523, in synoptic table. Dietz, 1890, pp. 27-28, revision and synopsis to 

 include D. terebrans (Oliv.), D. rufipennis XKirby), D. similis Lee., D. simplex Lee., 

 D. <i pproximatus n. sp., and D. frontalis; revised description of species, with syn- 

 onymy, figs. 1-6, epistqmata and antennae. Hopkins, 1894b, p. 280, author's extra, p. 7, 

 sexual characters of D. terebrans (Oliv.), D. frontalis Zimm. Blandford, 1897, p. 143, 

 synoptic table. Lovendal, 1308, pp. 86-87, PI. II, fig. 7, antenna, fig. 8, tarsus. 

 Hopkins, 1902a, pp. 3-4, secondary sexual characters, statistics, etc. Hopkins, 1906b, 

 pp. 143-147, larval mouthparts. 



DIVISION I. 



The distinctive characters common to the species of the first division 

 are as follows: 



Adult. Prothorax somewhat elongate and as broad as elytra; 

 anterior dorsal half of elytra without long erect hairs. 



Pupa. Vertex of head distinctly to faintly grooved, and with two 

 prominent to small frontal spines or granules on or toward the vertex 

 each side of groove. 



Larva. Abdominal tergites 8 and 9 without dorsal plates. 



Galleries. Egg galleries winding to straight; the eggs isolated or 

 in approximate groups, but never in masses; larval mines exposed 

 or concealed in inner bark. 



SUBDIVISION A. 



(Species numbers 1 to 8, inclusive.) 



The distinctive characters common to the species of the first sub- 

 division are as follows : 



Adult. Body somewhat slender; prothorax with sides but slightly 

 narrowed and not constricted toward the head; elytra with second 

 stria of declivity straight; second interspace not distinctly broader 

 hi middle: 



Sexes. Female: Pronotum with transverse ridge across anterior 

 area. Male: Pronotum without transverse ridge, but usually with 

 anterior area broadly impressed. 



Pupa. Elytra smooth; vertex of head faintly grooved and with 

 two small, widely separated frontal tubercles. 



Larva. Front with or without median convexity. 



Galleries. Egg galleries winding; larval mines exposed or con- 

 cealed. Pupal cells in outer bark; eggs isolated, never in groups. 



1. Dendroctonus brevicomis Le Conte. 

 (PI. Ill, fig. l.) 



Adult. Typical female: Length, 4.6 mm.; light brown. Elytral 

 declivity without long hairs. Head with front convex, slight eleva- 

 tions each side of a faint median groove. Elytral rugosities fine, 

 densely placed; striae obscure and but faintly or not at all impressed. 



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