ICHNEUMON-FLIES OF AMERICA: 1. METOPIFNAE 61 



Key to the subgenera of Metopius 



1. Lower tooth of mandible absent or present, when present attached to lower 



outer edge of upper tooth, not or weakly impressed inward toward mouth; 

 interantennal process of face compressed and with a median carina except 



in some non-Xearctic species of the subgenus Metopius 2 



Lower tooth of mandible present, impressed inward toward mouth so that it 

 is not on lower outer edge of upper tooth; interantennal process of face with- 

 out a median carina; margin of clypeus not reflexed or raised from base of 

 labrum 4 



2. Second recurrent vein with 2 bullae (fig. 166, b), interantennal process project- 



ing forward a little to form a compressed tubercle at top of face (fig. 166,b), 

 lower tooth of mandible basad of upper tooth by about 1.3 the basal width 

 of upper tooth, hind femur about 4 times as long as deep (fig. 166, b). 



Palaearctic 1. Peltocarus 



Second recurrent vein with 1 bulla, or rarely with 2; interantennal process 

 not projecting forward (figs. 167, a, and 168,a,b); lower tooth of mandible 

 absent, or if present basad of upper tooth by more than 1.5 the basal width 

 of upper tooth; hind femur about 3 times as long as deep (figs. 167,a, 

 168,a,b) 3 



3. Occipital carina extending below level of center of foramen magnum, in the 



majority of cases complete to the hypostomal carina; fiagellum not short 

 and blunt, its wider segments 1.2 to 1.85 as wide as long (fig. 167, a); lower 

 tooth of mandible often present but small; claws of front and middle tarsi 

 apparently simple, or sometimes pectinate on their basal 0.3. Holarctic, 



Oriental, and Australian 2. Metopius 



Occipital carina absent below level of center of foramen magnum; fiagellum 

 thick and blunt, the wider segments 2.0 to 3.0 as wide as long (figs. 168,a,b); 

 lower tooth of mandible entirely absent; claws of front and middle tarsi 

 pectinate on basal 0.3 to 0.65, or pectinate throughout. Nearctic. 



3. Cultrarius 



4. Prepectal carina turned weakly forward above sternaulus, gradually approach- 



ing front edge of mesopleurum but ending well separated from it (fig. 167, b); 

 interantennal process strongly concave and with wide raised lateral flanges. 



Neotropic and Nearctic 4. Peltalcs 



Prepectal carina turned sharply forward above sternaulus, abruptly approach- 

 ing front edge of mesopleurum, then closely paralleling it (fig. 169,a,b); 

 interantennal process fiat, convex, or concave, without strong lateral 

 flanges 5 



5. Frons with a median lamella which is continuous with upper end of inter- 



antennal process of face. Holarctic 5. Tyiopius 



Frons with a separate median horn or compressed tooth which is connected 

 with upper end of interantennal process of face by a ridge. Palaearctic and 

 Oriental 6. Ceratopius 



1. Subgenus Peltocarus 



Figure 166,b 



Peltocarus Thomson, 1887, Deutsche Ent. Zeitschr., vol. 31, p. 196. Type: 

 Peltocarus croceicornis Thomson; designated by Viereck, 1914. 



CUmontia Michener, 1941, Pan-Pacific Ent. vol 17, p. 2; new synonymy. Type: 

 Ichneumon micratorius Fabricius; original designation. 



Facial shields omewhat escutcheon-shaped, but the sides converging 

 ventrally and continued across the bottom in a parabolic curve and 



