8 U. S. NATIONAL MUSEUIVI BULLETIN 209 



Key to the subfamilies of Psammocharidae 



1. Second sternite of female (and often of male) with a sharp transverse groove 



(fig. l,c); middle and hind femora never with one or several subapical spine- 

 like bristles set in grooves or pits; last segment of tarsi sometimes with a 

 pair of sublateral ventral rows of bristles, never with a distinct median 

 ventral row; subdiscoidal vein never with a definite downward deflection 

 at its base (thus the lower inner corner of the third discoidal cell is simple 

 and without a pocket); dorsal edge of hind tibia frequently with a series 

 of teeth (fig. l,e); spinelike bristles at apex of hind tibia of rather uniform 



length, not splayed (fig. l,e) Pepsinae (p. 8) 



Second sternite of both sexes without a sharp transverse groove, though 

 sometimes with a broad, weak, transverse impression; middle and hind 

 femora usually with one or several apical dorsal spinelike bristles set in 

 grooves or pits (fig. l,d) 2 



2. Spinelike bristles at apex of hind tibia rather long, irregular in length and 



spacing, and splayed (fig. 1,/) ; subdiscoidal vein of forewing usually deflected 

 downward at its base, thus forming a small pocket at the lower inner corner 

 of the third discoidal cell (p, fig. l,a); middle and hind femora usually with 

 one or several spinelike subapical bristles set in grooves or pits (fig. l,d); 

 preapical bristles on under side of last segment of tarsus, when present, 

 arranged chiefly or entirely in a median longitudinal row; female subgenital 

 plate without a median longitudinal keel or sharp fold; labrum often con- 

 cealed beneath the clypeus; dorsal edge of hind tibia rarely with a longi- 

 tudinal ridge or serration Psammocharinae ' 



Spinelike bristles at apex of hind tibia shorter, of rather uniform length; sub- 

 discoidal vein of forewing never with a definite downward deflection at Its 

 base (thus the lower inner corner of the third discoidal cell is simple and 

 without a pocket) ; middle and hind femora usually without, or with small 

 and inconspicuous spinelike bristles set in grooves or pits; preapical bristles 

 on under side of last segment of tarsus, when present, often not arranged in 

 a single median row; female subgenital plate with a longitudinal keel or 

 sharp fold, at least apically; labrum exposed; dorsal edge of hind tibia 

 smooth Ceropalinae (p. 220) 



SuLfamily Pepsinae 



The salient subfamily characters are listed in the key to sub- 

 families. The sharp transverse groove on the second sternite of all 

 females (fig. l,c) and some males is the easiest recognition mark. 

 Some members of the other two subfamilies have a broad, weak, 

 transverse impression in this same position which should not be con- 

 fused with the sharp groove of the Pepsinae, The lower inner corner 

 of the third discoidal cell is without a pocket, the spinelike bristles at 

 the apex of the hind tibia are of rather uniform length and not splayed 

 (fig. l,e), and the dorsal edge of the hind tibia is often serrate. 

 The first character will distinguish the Pepsinae from most of the 

 Psammocharinae, but not from the Ceropalinae. The second 



> The Psammocharinae are not treated further in this paper. The Nearctic species have been revised 

 by Evans and Bradley in the papers referred to on page 2, 



