Studies of North American Bees 37 



medial, second submarginal slightly broader above than third. Legs 

 brownish red, the coxae, spots on trochanters behind, lines on first four 

 femora beneath and most of posterior femora except knees and a line 

 on anterior face, black or blackish. Abdomen reddish, tergite i with 

 the basal half and a subapical line black, tergites 2-6 with broad complete 

 yellow bands, that on 2 slightly narrowed medially, the others of subequal 

 width throughout, lateral posterior margins of bands on tergites 3-6 

 emarginate, on 5 and 6 the emarginations having cut through and the 

 usual isolated lateral spots having become obsolete. Apex red, feebly 

 notched, its sides prominently elevated. Venter brownish red, a cordate 

 black mark on sternite i and basal areas of black on sternites 2-5, 6 

 brownish red slightly suffused with yellow. 



Type. — Sioux county, Nebraska, ^lay (L. Bruner), J*. 



This species apparently also belongs to the simplex group, dif- 

 fering from A^. simplex Rob., chiefly in the lack of clear yellow 

 on the legs, the reddish ground color of the abdomen with com- 

 plete, scarcely medially narrowed bands, the yellow and red 

 mesopleural spot, red mesoscutellum, yellow collar and first 

 flagellar joint in front, the more extensively red flagellum and the 

 longer upward extension of the lateral face marks. From .V. 

 salicicola, just described, it dififers in the subparallel orbits, more 

 distinctly sinuate flagellum, red mesoscutellum, mesopleural spot 

 and complete abdominal bands. iV. salicis Rob. differs in the 

 shorter flagellar joints, strongly notched apex and clear yellow 

 markings on the legs. From A". paUidella and A", aprilina it 

 differs in the feebly notched apex, red mesoscutellum, subparallel 

 orbits, etc., while the color of the legs, spots on collar and 

 mesopleura, red mesoscutellum, etc., separate it at once from N. 

 ruidosensis. It is highly probable that N. parallela may even- 

 tually prove to be the male of A\ nigrociliata or N. ochrohirta, 

 just described, or of A^. velutina or A^. angnlata, described on a 

 following page, but lack of any definite evidence prevents me 

 from assigning it to any such position at present, its structural 

 characters not indicating any one of these species in particular. 

 On the other hand, it may easily prove to belong to a female at 

 present unknown and undescribed. 



37 



