No. 22.] HYMENOPTERA OF CONNECTICUT. 29 



4. Front wings with first abscissa of Ms present; antennae in- 



serted between eyes above base of clypeus, with bases of 



antennae fully exposed 5 



Front wings with first abscissa of M wanting; antennae in- 

 serted below level of eyes at base of clypeus under a trans- 

 verse ridge of the front, their bases concealed 



ORYSSID^: p. 175 



5. Front wings with a distinct cell between costa and Sc + R + 



M; medio-cubital cross-vein subequal in length to first 



abscissa of media 6 



Front wings without a cell between costa and Sc + R + M; 

 medio-cubital cross-vein from three to five times as long 

 as first abscissa of media CEPHID^E p. 172 



6. Front wings with free part of Sd always present; first ab- 



scissa of media extending lengthwise of wing; the last 

 abdominal tergite not ending in a triangular or lanceolate 



process XIPHYDRIID^E p. 168 



Front wings with free part of Sci always wanting; first ab- 

 scissa of media extending crosswise of wing; last ab- 

 dominal tergite ending in a triangular or lanceolate 

 process SIRICID^ p. 169 



XYELIDAE. 

 Key to Genera. 



1. Front wings with free part of M arising a considerable dis- 



tance beyond point of union of R + M and Sc 2 ; hind 

 wings with free part of Rs wanting; claws with a minute 

 tooth-like protuberance at base or with a long slender 



seta at apex 2 



Front -wings with free part of M arising distinctly before 

 point of separation of R and Sc 2 ; hind wings with free 

 part of R 5 present; claws cleft or with a large tooth within 

 at apex 3 



2. Front wings with Sc not coalesced with R + M, so that free 



part of Sc 2 appears like a cross-vein between apex of Sc 



and R + M Pleuroneura p. 30 



Front wings with Sc coalesced with R + M, so that the free 

 part of Sc 2 is obliterated Xyela p. 30 



3. Front wings with free part of R subequal in length to 



R + Sc 2 4 



Front wings with free part of R distinctly shorter than 

 R + Sc 2 , frequently less than one-half the length of R 

 + Sc 2 5 



4. Claws with a large erect tooth within at middle 



Odontophyes p. 30 

 Claws cleft, two parts of cleft parallel Megaxyela p. 31 



