246 UNIVERSITY OF COLORADO STUDIES 



26. Hair of face long and entirely black nigrihirta (Ashmead) 



Hair of face not, or not entirely, black 27, 



27. Clypeus and lower comers of face yellow bridwelli Ckll. 



Clypeus yellow, but not sides or corners of face 28. 



Clypeus not yellow 29. 



28. Malar space very large (Boulder, fls. Ribes) . leptanthi Viereck & Cockerell 

 Malar space rudimentary hellanthi Robertson 



29. Flagellum red beneath; small species salicinella Ckll. 



Flagellum dark 30. 



30. Very small, little over 5 mm. long fragariana Graenicher 



Larger 31. 



31. Abdomen with a purplish tint, and thin white hair-bands geranii Robertson 

 Abdomen not metaUic 32. 



32. Abdomen with broad conspicuous hair-bands; hair of thorax above very yellow 



mentzelise Ckll * 

 Abdomen not thus banded 33. 



33. Area of metathorax coarsely sculptured 34. 



Area of metathorax granular; sides of face with black hair . . . 35. 



34. Flagellum conspicuously moniliform claytoniae Robertson 



Larger; flagellum hardly moniliform cratsegi Robertson 



35. Larger; hair of thorax wholly pale, slightly yellowish carlini Ckll. 



Smaller; hair of thorax grayish-white, with some black cockerelli Graenicher 



A female of A. prunorum giUettei, taken at Boulder, May 11, at flowers of Salix, 

 is peculiar for having the red on the abdomen confined to the hind margins of the 

 segments, so that it looks like a very handsome new species. 



From an observation made by my wife, there is reason to believe that A. portera 

 and A. leptanthi are the sexes of one species, notwithstanding their entirely dif- 

 ferent appearance. If so, the insect formerly cited as the female of leptanthi must 

 represent an undescribed species. 



HALICTOIDES Nylander 

 Larger, at least 9 mm. long; intense black, face with black hair (Ward, fls. Gilia) 



maurus (Cresson) 

 Smaller, much less than 9 mm., hair of face not black (Ward, fls. DrymocalUs) 



harveyi Ckll. 

 The male harveyi has a dense brush of pure white hair covering the clypeus. Halic- 

 toides looks much like Panurginus, but the marginal cell is pointed, not truncate. 



PANURGINUS Nylander 

 Clypeus yellow, but no other yellow on face ; first recurrent nervure almost or quite 

 meeting first transverso-cubital; male (Ward, fls. DrymocalUs) cressoniellus Ckll. 

 Clypeus and a large mark on each side of face yellow; male innuptus Ckll. 



Clypeus black, females i. 



I . First recurrent nervure entering second submarginal cell at a considerable distance 

 from its base; nervures ferruginous (Boulder, fls. sunflower, Aug. 8, W. P. Ckll.) 



innuptus Ckll. 



