Studies of North American Bees 35 



N. nigrociliata, it differs conspicuously in the lack of the black 

 hairs of the scape, vertex and mesonotum as well as by the 

 ochreous hair, in having a large black spot about the insertion of 

 antennae which encroaches down in the clypeal sutures (face 

 all red in calif orniae), and in having the middle and hind femora 

 with black on the basal areas behind (lacking in calif orniae 

 except a faint blackish stripe on posterior face of hind femora). 

 From A^. atrofrontata CklL, it differs in the shorter third an- 

 tennal joint (longer than fourth in atrofrontata), the largely 

 black posterior face of hind femora (red in atrofrontata), the 

 bright ochreous hair, etc. It is not at all improbable that with 

 the accumulation of more specimens further study will necessitate 

 the reduction of some of these nominal species to geographical 

 races. 



Nomada (Nomada) salicicola n. sp. 



S- Length 5.5-7 mm. Black, the clypeus, labrum, mandibles except 

 tips, small triangular lateral face marks produced along anterior orbits 

 in a line which fails to attain the level of insertion of antennae, line 

 under eye, scape in front, tubercles (these sometimes red), sometime? 

 two linear spots on collar, two spots on mesoscutellum, and abdominal 

 maculations, yellow. Flagellum bright brownish red, the first four joints 

 above, together with the scape behind, black, antennal joint 3 three-fifths 

 as long as 4, the median joints sometimes scarcely longer than wide. An- 

 terior orbits converging below, the interorbital width at narrowest point 

 fully one-seventh less than the width at vertex. Head and thorax 

 coarsely and closely punctured. Tegulae red. Wings hyaline, apically 

 slightly darkened, nervures brown, stigma paler brown. Basal nervure 

 slightly basad of transverso-medial, second submarginal cell unusually 

 narrow and parallel-sided. Legs brownish red, the knees sometimes 

 distinctly yellowish, the coxae, trochanters behind, posterior face of 

 femora and tibiae more or less, and a suffusion on anterior face of hind 

 femora black or blackish. Mesoscutellum scarcely subbilobed. Abdomen 

 Mack, the apical margins of segments 2-4 sometimes deeply stained with 

 reddish, tergites 1-6 with yellow bands, that on i narrow and complete 

 but stained more or less with red, those on 2-5 more or less constricted 

 on anterior margin medially and sometimes interrupted on 2 and 3, on 

 the posterior margin of each lateral half medially more or less of an 

 emargination, most distinct on 4 and 5 where it nearly or completely 

 cuts through the band, the band on 6 complete and entire. Apex narrow, 

 feebly notched, reddish. Venter brownish red with more or less distinct 

 yellowish lines on sternites 3-5 and a yellow spot on 6; a cordate black 



35 



