236 Trans. Acad. Sci. of St. Louis. 



which is generally of a dark testaceous with the last two seg- 

 ments black, may become wholly black, while in others, such 

 as discojm?icta(us, the black color of the last two segments 

 never shows any tendency to speacl anteriorly. Although 

 some are very variable, others, such as the longiusculus group, 

 including the pale Sonoran species, appear to be quite con- 

 stant in the limited ornamentation that they possess. The 

 secondaiy sexual characters are very simple, consisting only 

 of a small deep and acute cusp-like emargination of the sixth 

 ventral and are but slightly diversified, rendering a satisfac- 

 tory classification of the species very difficult ; that suggested 

 below is merely provisional and a much better one may be 

 devised in the future. The twenty-one species in my cabinet 

 may be known by the following characters: — 



Species of the Atlantic coast to eastern Texas and including the entire 



Mississippi Valley 2 



Species of the Sonoran province 15 



Species of the true Pacific coast fauDa, extending inland to the northward 

 as far as the Rocky Mountains 17 



2 — Head invariably black or piceous-black 3 



Head always pale in coloration 14 



3 — Elytra pale, maculate with black, occasionally entirely black 4 



Elytra completely pale in color, never maculate 13 



4 — Large species, not less than 4.4 mm. in length, the general color dark 



throughout 5 



Small species, not exceeding 3.7 mm. in length when the abdomen is not 

 excessively extended 8 



5 — Elytra distinctly longer than the prothorax 6 



Elytra equal to or shorter than the prothorax 7 



6 — Parallel, feebly shining, black throughout, and legs and antennae pale, 



the elytra pale in apical fourth, the pale area increasing in length 

 inwardly, occupying almost apical half on the suture and extending 

 feebly along the latter to the base; sculpture of the head and pronotum 

 rather coarse, dense and somewhat longitudinally confluent as usual; 

 punctures of the elytra strong and rugose but distinctly separated, of the 

 abdomen finer but strong, asperulate and arranged in the usual trans- 

 versely wavy series; head large, slightly wider than the elytra, longer 

 than wide, the eyes convex and prominent and at slightly more than 

 their own length from the base; basal part behind them obtrapezoidal, 

 with the angles broadly rounded; prothorax oval, much longer than 

 wide, widest and broadly rounded at the sides at apical third; elytra 

 distinctly longer than wide, narrowed gradually toward tip, obviously 

 wider and longer than the prothorax; abdomen at base as wide as the 

 elytral apex, slightly wider posteriorly. Male distinctly more slender 

 than the female, with the head and prothorax larger when compared 



