THE GENUS DENDROCTONTJS. 81 



D. simplex Lee, D. frontalis Zimm., eliminating CarjjJioborus bi/urcus Eichh. Eich- 

 hoff, 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. r-ufipennis (Kirby), D. similis Lee, D. simplex Lee, 

 D. approximatus n. sp., and D. frontalis; revised description of species, with syn- 

 onymy, figs. 1-6, epistomata 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, 1398, 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 sHghtly 

 narrowed and not constricted toward the head; elytra with second 

 stria of declivity straight; second interspace not distinctly broader 

 in middle: 



Sexes. — Female: Pronotum luitJi transverse ridge across anterior 

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

 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. in, fig. 1.) 



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

 dechvity without long hairs. Head with front convex, shght eleva- 

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

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



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