174 U. S. NATIONAL MUSEUM BULLETIN 216 



16. Lateral longitudinal carina of propodeum absent basad of the spiracle, else- 



where weak; median longitudinal carinae of propodeum entirely absent 



(fig. 188,h). atriceps group 19. atriceps Walsh 



Lateral longitudinal carina of propodeum complete and strong; median lon- 

 gitudinal carinae of propodeum present (figs. 188,f,g,i,j) 17 



17. Median carinae of propodeum subparallel, not bent inward just basad of posi- 



tion of costula but sometimes gradually convergent basally (fig. 188,f); 

 first abdominal tergite slender, 2.7 to 3.1 as long as it is wide at its basal 



corners, montivagus group 18 



Median carinae of propodeum bent inward just basad of position of costula 

 (figs. 188,g,i,j); first abdominal tergite stouter, 1.4 to 2.5 as long as it is 

 wide at its basal corners 20 



18. Tergites 1 through 6 with a large median apical stramineous triangle; side of 



frons entirely pale; median carinae of propodeum convergent basally. 



16. spinalis, new species 



Tergites 1 through 6 entirely black; side of frons partly or entirely black; 



median carinae of propodeum subparallel 19 



19. Side of frons entirely black; apex of hind femur yellow (fig. 192,e). 



14. montivagus, new species 

 Side of frons mostly yellow; apex of hind femur fuscoferruginous (fig. 192,f). 



15. ochreatus, new species 



20. Pale spots at top of eyes elongate and somewhat convergent posteriorly; 



second lateral area of propodeum completely covered with hairs (fig. 188,g) ; 

 second abdominal tergite about 0.75 as long as wide, its punctures rather 

 dense and sharp; basal 0.2 of hind tibia yellow, beyond which it is abruptly 



ferruginous or fuscous (figs. 192, h,i). signifrons group 21 



Pale spots at top of eyes subcircular or subtriangular; second lateral area of 

 propodeum usually only partly hairy or almost or quite bare (figs. 188,i,j); 

 second abdominal tergite about 0.6 to 1.6 as long as wide; hind tibia basally 

 fuscous, ferruginous, or whitish, but not exactly as described above . . 22 



21. Frons without a median high compressed carina, though a little produced 



centrally ; hind femur whitish to blackish, the apex always yellow or whitish 



(fig. 192,h) 17. flavifrontalis Davis 



Frons with a median high compressed carina which almost meets the inter- 

 antennal process of face; hind femur ferruginous, sometimes a little infus- 

 cate or yellowish on the apex (fig. 192,i) . . . 18. dentifrons, new species 



22. Sternaulus distinct and rather sharp, extending about 0.3 the length of the 



mesosternum; punctures on abdominal tergites so fine and weak that they 

 are difficult to see; hind tibia stramineous, fuscous at base and with an 

 indistinct infuscate stripe on front side (fig. 193, a), sulcatus group. 



20. sulcatus, new species 



Sternaulus not distinct; punctures on abdominal tergites of moderate size 



and moderately conspicuous; hind tibia colored otherwise in the Nearctic 



species, tibialis group 23 



23. Hind femur and tibia entirely blackish .... 25. tencbrosus, new species 

 Hind femur and tibia largely pale or conspicuously marked with white, 



yellow, or fulvous 24 



24. Hind tibia fulvous, without any whitish area, but the basal and/or apical 



0.15 ± often infuscate 25 



Hind tibia whitish basally, subbasally, medially, or almost entirely, the rest 

 blackish, infuscate fulvous, or in E. albifrons fulvous with the apex in- 

 fuscate 28 



