l82 UNIVERSITY OF COLORADO STUDIES 



c Females without facial foveae; metallic or black bees, rarely with 

 the abdomen orange or red, distinguished from Andreninae by the 

 strongly curved basal nervure; hind spur of hind tibia in females 

 often with long teeth. Halictinae. 



aa Colors black or greenish, rarely at all brilliant; size often 

 small; three submarginal cells; species numerous. 



Halictus Latr. (P.) 

 bb Head and thorax metallic; size very small; like Halictus, 

 but with only two submarginal cells. 



Dialictus Rob. (P. D.) 

 cc Brilliant green (rarely blue or crimson) species, the color 

 not conspicuously different in the sexes; eyes emarginate 

 in front; a group invading North America from the Neo- 

 tropical region; tongue sometimes quite long. 



Augochlora Smith (S.) 



dd Brilliant green species, the abdomen sometimes dark or 



yellowish; males with abdomen striped with yellow and 



black. Agapostemon Smith (S.) 



d Inquilinous or parasitic bees, with the head and thorax black, the 

 abdomen red; three submarginal cells. Sphecodinae. 



Sphecodes Latr. 1 (P.) 



2 Tongue elongate, though not as long as in some of the higher groups; only 

 two submarginal cells except in Protandrena, which has three; never brilliantly 

 metallic, though sometimes {Perdita) the head and thorax green; often with 

 yellow markings. PANURGIDAE. 



a Three submarginal cells; black species, the face with yellow markings; 

 marginal cell truncate at end. Protandrena Ckll. (S.) 



b Two submarginal cells. 



Marginal cell pointed on costa. Halictoides Nyl. 2 (P.) 



Marginal cell truncate (obliquely in some). 



Marginal cell short and very broadly truncate; 

 small species with nearly always light 

 markings on abdomen. 



Perdita Smith (N.) 

 Marginal cell elongate. 



Abdomen with pale- markings not due to 

 hair. Spinoliella Ashm. (N.) 



Abdomen without pale markings. 



Truncation of marginal cell little 

 oblique. 



Pangurginus Nyl. (P.) 

 Truncation of marginal cell con- 

 spicuously oblique; first 

 recurrent nervure meet- 

 ing first transverso-cubi- 

 tal. Only one species, 3 

 which visits Malvastrum. 

 Greeleyella Ckll. (N.) 



1 The subgenus Proleraner Rob. has males which appear in the spring with the females, which is not the 

 case with other Halictinae. For a list of the species of Sphecodes, see Psyche, pp. 107-110, October, 1907. 



* The related Californian genus Amblyapis Ckll. (type A. ilicifolia Ckll.) is separated by the short palpi, 

 second and third joints of labial palpi produced on one side apically, and blade of maxilla very short and 

 obtuse. A. ilicijolice is a small (si mm. long) black bee with greyish-white hair. 



3 Since this was written a second species, collected in Texas, has been received. 



