No. 22.] HYMENOPTERA OF CONNECTICUT. 53I 



Labial palpi with three joints BELYTID^E p. 568 



11. Labial palpi with two joints, hind wings with no basal cell 



DIAPRIID.E p. 561 

 Labial palpi with three joints, hind wings always with a 

 basal cell BELYTID^ p. 568 



12. Mandibles without teeth, antennae with thirteen joints 



SERPHID; p. 573 

 Mandibles with teeth, antennae with fourteen or fifteen joints 



helorid;e p. 576 



PLATYGASTRID.E. 



The species of this family are parasites of the larvae of gall- 

 gnats or midges and crane-flies, etc. 



Key to Genera. 



1. Submarginal vein in front wings ending in a stigma or knob; 



tarsi 5-jointed, antennae 10-jointed, front wings without a 



basal nervure 2 



Submarginal vein entirely absent or indicated only at base, 

 never knobbed 3 



2. Lateral ocelli nearer to eye margin than to front ocellus, 



basal segment of abdomen with a horn above 



Inostemma p. 532 

 Lateral ocelli nearer to front ocellus than to eye margin 



Isostasius p. 532 



3. Scutellum lengthened, not semicircular; if shortened, com- 



pressed at sides and furnished with a spine 4 



Scutellum not lengthened, semicircular, always unarmed.... 5 



4. Abdomen much lengthened; club of female antennae 5-jointed 



Polymecus p. 534 

 Abdomen not especially lengthened; club of female antennae 

 4-jointed; scutellum with a thorn, or sometimes only a 

 tubercle; lateral ocelli nearer to eye margin than to front 



ocellus; mesonotal furrows sometimes present 



Amblyaspis (includes Leptacis and Synopeas)*p. 532 



5. Scutellum flat or subconvex 6 



Scutellum convex or cushion-shaped 7 



6. Mesonotum without furrows; antennae 10-jointed, with a 



jointed club in female Anopedius p. 533 



Mesonotum with more or less distinct furrows; antennae 

 8-jointed in female, with an unjointed club Amitus p. 534 



7. Scutellum bare 8 



Scutellum with a tuft of hairs at tip; lateral ocelli not close 



to eye margin; club of antennae 5-jointed Trichasis p. 534 



8. Abdomen of usual length : 9 



Abdomen much lengthened Polymecus p. 534 



These genera are all included together, as they do not appear to be separable by any 

 trustworthy characters. 



