No. 22.] HYMENOPTERA OF CONNECTICUT. 201 



Microgaster Latreille. 



Key to Species. 



1. Propodeum with a more or less complete prominent median 



longitudinal carina, usually very coarsely rugose, never 



with an areola 2 



Propodeum without a prominent median longitudinal carina, 

 but with a more or less distinct median area or areola; sec- 

 ond dorsal abdominal segment much shorter than third; 

 basal joint of antennae stramineous beneath; mouth stra- 

 mineous, palpi whitish, wings hyaline; a stramineous band 

 on middle of dorsum of abdomen; legs stramineous, hind 

 tarsi dusky. Length of body 2.5 mm zonarius 



2. Second dorsal abdominal segment not separated from third 



by a deep transverse furrow, trilobed, rugose; mostly 



black with reddish legs; wings subhyaline 3 



Second dorsal abdominal segment separated from third by 

 a deep transverse furrow, the former segment not trilobed; 

 mesopleural furrow wanting or shallow and smooth 4 



3. Abdomen black above. Length 4 mm brevicaudus 



Abdomen mostly black; body 3 mm. long; lateral edge of first 



and second dorsal abdominal segments, yellow; third and 

 fourth dorsal segments partly reddish stramineous; ven- 

 tral portion of abdomen mostly reddish to yellowish stra- 

 mineous solidaginis 



4. Black; fore and mid legs, except coxae, almost entirely 



stramineous, all coxae black 5 



Black; antennae brown; legs nearly as in congregatiformis and 

 carinatus, but in addition the coxae and trochanters are stra- 

 mineous; hind femora not brown at apex, hind tibiae red- 

 dish stramineous, brown at apex; ventral portion of ab- 

 domen mostly brownish stramineous. Length 4 mm. 



gelechiae 

 5- Fore and mid proximal trochanters more or less blackish.. 6 

 Fore and mid proximal trochanters entirely stramineous or 

 reddish; second dorsal abdominal segment nearly as long 

 as first; lateral edge of first, second, third, and fourth seg- 

 ments more or less brownish stramineous, ventral por- 

 tion of abdomen mostly reddish; trochanters, femora, tibiae 

 and tarsi mostly stramineous or reddish; hind femora and 



tibiae brown at apex; hind tarsi brown. Length 3 mm 



brittoni 

 6. Basal half of abdomen yellowish beneath; third dorsal ab- 

 dominal segment partly indistinctly punctate carinatus 



Basal half of abdomen blackish beneath; third dorsal abdom- 

 inal segment partly longitudinally striate congregatiformis 



