H. C. FALL. 187 



straight, surface rather densely coarsely punctate, the interspaces 

 polished and scarcely punctulate. Scutellum short, transverse, mod- 

 erately pubescent. Elytra as wide as long, humeri well defined, sides 

 nearly parallel and broadly arcuate, striae fine, distinctly, rather closely 

 punctate, intervals finely punctulate, each with a series of distant, 

 larger punctures. Pygidium oblique, clothed rather densely with 

 ochreous pubescence, surface closely, coarsely punctate. Legs rufous, 

 posterior thighs moderately stout, armed with a long tooth and four 

 well developed acute denticles ; apical spur of hind tibia about one- 

 fourth the length of the first tarsal joint. Length, 4.6 mm. ; width, 

 2.75 mm. 



Jerome, Arizona. A single female example collected at 

 light, and sent to Dr. Fenyes, who kindly permits me to 

 retain the type. 



Only two other species in our fauna are known with four 

 denticles on the hind femora, vix. : julianus and quadri- 

 dentatus. Julianus is blackish with more variegated pubes- 

 cence of brown, white and ochreous, but without conspicu- 

 ous yellow line on the third interspace, the pygidium with 

 white basal spots, the antennas with joints 8-10 abruptly 

 blackish. Quadride?itatus is much smaller (3 mm.), and ac- 

 cording to description must be very much more elongate, 

 the elytra being nearly twice as long as wide, with the sides 

 posteriorly diverging. 



Group IX. 



The species of this group are small or minute, and char- 

 acterized by the presence of two or three small denticles 

 only on the hind femur. Horn placed here macrocerus and 

 seminulum . The latter and atomus, described below, conform 

 to this description in having two very small subequal well 

 separated denticles, which in the smallest examples become 

 so rudimentary as to be detected with difficulty. 



Flavicornis Sharp, which has in recent years been taken 

 in Arizona and Lower California, is described as having the 

 hind femur devoid of teeth or denticles. This may be true 

 of some specimens, but there are examples before me in 

 which either one or two very minute rudimentary denticles 

 are present, and there can be no doubt that the species is 

 more properly placed here than in Group V, where it looks 



TRANS. AM. ENT. SOC, XXXVI. JULY, 1910. 



