68 PROCEEDINGS OF THE NATIONAL MUSEUM vol.89 



thorax with long cilia; clypeal suture very faintly bi- 



arcuate; antennal club one-third longer than funicle 38 



Thorax rufous, densely punctate, with little or no trace 

 of a median impunctate area; lateral margins of thorax 

 with short cilia; clypeal suture strongly biarcuate, im- 

 pressed; antennal club subequal to funicle (genitalia 

 fig. &, i, j,) cushmani, new species 



38 (37). Sides of genitalia in en face view thickened near apex, not 



open to base through middle (fig. 6, g, h) dvincani (Barrett) 



Genitalia in en face view thickened all along the median 



line and open through the middle (fig. 6, e, /) ari2Sona, new species 



39 (36). All claws without a larger intercalated tooth; pygidium 



plane or very convex 40 



Outer front claw with a larger intercalated tooth, inner 

 claw without such tooth; pygidium normally convex; 

 sides of thorax subangularly dilated, margin very coarse- 

 ly crenate (genitalia fig. 10, m-o) texensis, new species 



40 (39). Pygidium very convex, densely and coarsely punctate and 



shining, with short procumbent hair; sixth abdominal 



segment plane (genitalia fig. 6, k-n) scuticeps (Bates) 



Pygidium plane, very sparsely and finely punctate, with 

 minute hair, surface subopaque; sixth abdominal with 

 a short and truncate lobe at middle (fig. 2, h) senez (Horn) 



KEY TO THE FEMALES OF LISTROCHELUS 



(The females of L. cavata, neomcxicana, cushmani, snowi, and duncani are either 

 unknown or, for reasons explained later, not included) 



1. All tarsal claws serrate or pectinate along a single margin; 



without any intercalated larger teeth 2 



Claws variable, one or both of those of front tarsus with a 



much larger tooth among serrations or pectinations 4 



2 (1). Glabrous above (Texas) senex (Horn) 



At least elytra densely hairy (Lower California) 3 



3 (2). Claws pectinate; clypeus reflexed at center apex, angles 



broadly rounded pilosipes, new name 



Claws minutely serrate; entire clypeal apex strongly re- 

 flexed, angles very sharply indicated peninsularis, new species 



4 (1). Thorax opaque, punctures not or hardly visible from a 



straight dorsal view; disk glabrous except at sides 5 



Thorax always distinctly punctured and usually highly 



polished; if opaque then with dense hairs 6 



5 (4). Elytra with long dense hair; first segment of hind tarsus 



somewhat expanded at apex (fig. 3, m) ; first front tarsal 

 segment with a strong inner spine, width of segment at 



apex one-half of its length tarsalis (SchaeflFer) 



Elytra with minute hair, or glabrous; first segment of hind 

 tarsus normal; first segment of front tarsus with a sharp 

 but small inner spine, the width of segment at apex 

 scarcely two-fifths its length falsa nogales, new subspecies 



6 (4). Entire dorsal surface highl}- pruinose and densely hairy; 



pygidium convex, polished, not impressed opacicoUis (Horn) 



