468 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



Bred from the larvse of a species of Catocala and from a larva 

 of a geometrid on birch. 



E. plathypenae Howard. 

 Female : differs from comstocki chiefly as follows : length 

 1.67 mm.; face entirely black; pronotum distinctly shagreened, 

 mesoscutel only slightly roughened, median carina distinctly 

 visible ; legs dark honey-yellow, hind coxae quite dark at bases ; 

 abdomen yellow above and beneath except for a narrow band 

 of black around the edge. Male: somewhat smaller than the 

 female ; scape with a leaf-like expansion beneath, otherwise 

 similar to the female. 



Bred from a larva of Plathypena scabra. Listed as an Ameri- 

 can parasite of a cosmoplitan insect. 



PTEROMALID^E. 

 Key to Genera. 



1. Anterior femora enlarged 18 



Anterior femora not enlarged 2 



2. Posterior tibiae i-spurred; head very large, broad, excavated 



in front, with two acute tubercles on each side Cratomus p. 483 

 Posterior tibiae 1- or 2-spurred; head not especially large.. 3 



3. Anterior edge of clypeus acutely bidentate in the middle; 



marginal vein of anterior wings often thickened 4 



Anterior edge of clypeus not bidentate; marginal vein not at 

 all or very slightly thickened; wings with the stigmal 

 club always quite pronounced; posterior tibiae i-spurred. ... 6 



4. Anterior wings with a delicate marginal vein; abdominal 



petiole punctate above, longer than wide 5 



Anterior wings with a thick marginal vein; abdominal pet- 

 iole shorter than the posterior coxae; parapsides not dis- 

 tinctly defined Pachyneuron p. 481 



5. Abdominal petiole longer than posterior coxae; male palpi 



normal; head with compressed cheeks; parapsides not 

 plainly defined; second and third abdominal segments 



very large Sphegigaster p. 483 



Abdominal petiole not longer than posterior coxae; second 

 abdominal segment deeply emarginate ; male palpi abnor- 

 mal; vertex of head acute in the middle; parapsides indis- 

 tinct Cyrtogastcr p. 482 



6. Antennal club not subulate 7 



Antennal club subulate in female or conico-acuminate in 



male; metathorax punctate, without a fold, without a 

 spiracular sulcus 16 



