36 U. S. NATIONAL MUSEUM BULLETIN 216 part s 



21. Frons with a median pair of horns that are placed side by side, the horns 



either entirely separate or on a common base (see from above); areolet 



about 1.5 as wide as high 25. Cryptanura (p. 426) 



Frons with a single median horn, the horn sometimes with a dorsal tine ... 22 



22. Second tergite with close, strong punctures; petiole bordered ventrolaterally 



by a strong carina; areolet 0.7 to 1.0 as wide as high. 



24. Listrognathus (p. 407) 

 Second tergite almost impunctate; petiole bordered ventrolaterally by a 

 weak, obsolescent carina; areolet about 1.3 as wide as high. 



26. Chamula (p. 430) 



23. Mediella vein weakly arched, near its apical 0.4 almost straight 24 



Mediella vein strongly arched, near its apical 0.4 strongly curved ... 25 



24. Areolet not wider than high (fig. 321, b); median part of apical transverse 



carina of propodeum present, approximately in line with or a little basad 

 of the sublateral crests; ovipositor sheath about as long as first tergite. 



27. Camera (p. 432) 

 Areolet wider than high (fig. 322,a) except in M. eisenii; median part of apical 

 transverse carina of propodeum either absent or much basad of the sub- 

 lateral crests; ovipositor sheath longer than first tergite. 



28. Mesosteniis (p. 434) 



25. Brachiella vein lacking; body form slender; areolet only moderately small. 



18. Hemisphragia (p. 378) 

 Brachiella vein present 26 



26. Apical transverse carina of propodeum complete and strong; propodeum with 



longitudinal as well as transverse carinae (fig. 318,b); ovipositor sheath 



about as long as first tergite 21. Pachysomoides (p. 398) 



Apical transverse carina of propodeum incomplete, absent at least at center; 

 propodeum without longitudinal carinae 27 



27. Base of second discoidal cell pointed or strongly narrowed (fig. 319,a); ovi- 



positor sheath a little shorter than first tergite . . 22. Acerastes (p. 403) 



Base of second discoidal cell broadly truncate; ovipositor sheath longer than 



first tergite 28 



28. Apical part of axillus vein (the short vein in anal part of hind wing) diverging 



from anal margin of wing (fig. 307, b) ; nervulus at or a little distad of basal 

 vein; mesoscutum broad and rather flat; subapical segments of female 

 fiagellum wider than long. Subtribe Baryceratina, in part. 



Baryceros (p. 23) 



Apical part of axillus converging to anal margin of wing; nervulus at or basad 



of basal vein; mesoscutum narrower and more arched; subapical segments 



of female fiagellum longer than wide 29 



29. Base of first tergite with a lateral subtriangular point or swelling opposite 



attachment of extensor tendon (usually strong and sharp in female, weak 

 and blunt in male); second tergite of female with dense hairs. 



19. Diapetimorpha (p. 380) 



Base of first tergite entirely without a lateral projection opposite attachment 



of extensor muscle 30 



30. Apex of clypeus without a distinct median point (fig. 318,a) or when with a 



median point it is not truncate; second tergite of female sparsely punctate; 

 first tergite of moderate length, its spiracle well behind the middle. 



20. Lymeon (p. 393) 



Apex of clypeus truncate and with a small median point (fig. 310,a); second 



tergite of female rather densely punctate; first tergite short and stout, its 



spiracle only a little behind the middle 4. Mallochia (p. 93) 



