396 bulletin: museum of comparative zoology. 



5. Antennal scapes with very few erect hairs, .nepticula Wheeler. 

 Antennal scapes with numerous erect hairs . . . nevadensis Wheeler. 



6. Antennal scapes with erect hairs 7 



Antennal scapes without erect hairs 8 



7. Hairs on antennal scapes coarse and clavate .... impexa Wheeler. 

 Hairs on antennal scapes delicate, not clavate. 



microgyna Wheeler. 



8. Clavate hairs on head, thorax, and gaster rather short. 



microgyna rasilis Wheeler. 

 Clavate hairs on head, thorax, and gaster longer. 



microgyna rasilis var. spicata, var. nov. 



EXSECTA group. 



Workers. 



1. Nearctic forms 2 



Palaearctic forms 6 



2. Antennal scapes thickened towards their tips 3 



Antennal scapes not thickened towards their tips 5 



3. Posterior half of head black ulkei Emery. 



Posterior half of head brown or red 4 



4. Gaster brown, subopaque or shghtly shining. 



ulkei var. hebescens, var. nov. 

 Gaster black, more opaque and pubescent. 



exsectoides opaciventris Emery. 



5. Petiole thick and narrow, with sharp but not cultrate border, 



transversely truncated exsectoides var. hesperia, var. nov. 



Petiole thin, broad, with a sharp, cultrate border which is not 

 transversely truncated 



exsectoides Forel and var. davisi Wheeler. 



6. Head long, its posterior border deeply excised; body opaque or 



but feebly shining 7 



Head shorter, its posterior border less deeply excised; body more 

 shining suecica Adlerz. 



7. Clypeus without a transverse impression behind its anterior 



border; maxillary palpi long 8 



Clypeus with a transverse impression behind its anterior border; 

 maxillary palpi short 10 



