H. C. FALL. 169 



distinct fovea, which is more densely sculptured and pubes- 

 cent. In these species, while there is no projecting lobe, the 

 posterior margin of the segment is usually arcuately promi- 

 nent at middle, which peculiarity is generally visible in some 

 degree also in the females. In pulloides. bhtstulus and 

 fumatus the longer hairs are scarcely evident, but the fovea 

 can usually be discerned. 



The following table will serve fairly well for the identifi- 

 cation of the species now known, but I have been unable to 

 arrange them in a satisfactory linear series ; indeed, I doubt 

 if such an arrangement is possible : 



1. Vertex with short, broadly transverse, subtriangular, glabrous, im- 



punctate area ; body elongate, pygidium strongly oblique, 

 apical spur of hind tibia short ; species of more than aver- 

 age size. 



Very elongate, depressed, last ventral concave, more strongly so 

 in the o", and in both sexes nearly as long as the three 

 preceding. (Texas to Lower California.) 



protractus Horn. 



Less elongate and more convex, last ventral not concave, about 

 as long as the preceding in the o*, longer but not exceed- 

 ing the two preceding in the 9 . 

 Black, prothorax and base of elytra sometimes rufous or rufes- 

 cent, pubescence uniformly cinereous, eyes flattened and 

 not more prominent posteriorly than the sides of the head. 



(Texas, Arizona.) amicus Horn. 



Ferrugineous or brown, pubescence brown variegated with gray- 

 ish lines and spots ; eyes normally prominent. (Browns- 

 ville, Texas.) sallaei Sharp. 



2. Vertex without glabrous impunctate area. 



Body above wholly or in great part rufotestaceous to ferru- 

 ginous 3. 



Body above wholly or in great part black 4. 



3. Scutellum elongate oblong, nearly twice as long as wide, pygidium 



strongly oblique. 

 Pygidium of 9 with two longitudinal parallel, dark, glabrous im- 

 pressions near the apex ; fourth antennal joint of d 1 not or 

 but slightly wider than the third. (Texas to Lower Cali- 

 fornia.) uniformis, desert or um, prosopis Lee. 



Pygidium of 9 without impressions ; antenna; more elongate, the 

 fourth joint of the c? nearly twice as wide as the third. 

 (Texas.) prosopoides Schf. 



TRANS. AM. ENT. SOC, XXXVI. (22) JULY, 1910. 



