ICHNEUMON-FLIES OF AMERICA: 1. METOPIINAE 13 



pale yellow. The legs are mostly fulvous or ferruginous with the 

 hind coxa frequently blackish. The wings of all Nearctic species are 

 hyaline with the stigma and veins dark, but the veins at the wing 

 bases yellow. Variation in details of head and leg coloration give 

 specific characters. 



This genus is worldwide, but with only a moderate number of 

 species. There are ten in the Nearctic region. Adults occur in 

 rather open, dry situations, usually among shrubs or low trees. 



Most species of Chorinaeus are difficult to distinguish, requiring 

 careful consideration of some rather small and variable specific dif- 

 ferences. Possibly not all of the species in the material studied have 

 been recognized and adequately characterized, but a better treatment 

 probably must wait for better study series. We have a residue of 11 

 Nearctic specimens not assigned to any species, and though the major- 

 ity belong probably to Chorinaeus Junebris, there may be some addi- 

 tional new species among them. 



Key to the Nearctic species of Chorinaeus 



MALES 



(The males of emorsus and labiosus are unknown.) 



1. Pronotum with small setiferous punctures from its dorsal margin down almost 



to its trough; longitudinal carinae of first tergite that are just above and 

 below the spiracle meeting apically in about a 25° angle; propodeal spiracle 

 usually nearer lateral carina than pleural carina; front wing 4.5 to 7.0 mm. 



long; hind coxa black, paler apically 1. longicalcar Thomson 



Pronotum with small setiferous punctures from its dorsal margin down about 

 0.66 the distance to its trough; longitudinal carinae of first tergite just above 

 and below the spiracle meeting apically in about a 45° angle; propodeal 

 spiracle not nearer lateral carina than pleural carina; front wing 3.0 to 5.5 

 mm. long 2 



2. Apex of penis with 4 to 15 strong bristles on each side 3 



Apex of penis without bristles 4 



3. Second segment of middle tarsus about 1.3 as long as wide; front spur of 



middle tibia about 1.0 as long as hind spur; apex of penis with 7 to 15 



bristles on each side 2. aequalis, new species 



Second segment of middle tarsus about 2.5 as long as wide; front spur of 

 middle tibia about 0.75 as long as hind spur; apex of penis with 4 to 6 bristles 

 on each side 3. excessorius Davis 



4. Mandible 1.8 to 2.1 as long as wide, its upper tooth a very little larger and 



and longer than its lower tooth; hind coxa largely or entirely blackish . . 5 

 Mandible 2.1 to 2.2 as long as wide, its upper tooth distinctly larger and 

 longer than its lower tooth; hind coxa ferruginous to black, usually ful- 

 vous 6 



5. Flagellum with about 28 segments; yellow on frons extending upward to a 



little above center of eye emargination; body punctation moderate. 



4. californicus Ashmead 



