Studies of North American Bees 25 



species, while the feebly bilobed mesoscutelhmi and fuscous- 

 margined tergites are further distinguishing marks. It comes 

 closest, probably, to A'', carolinae, but the male has a strong super- 

 ficial resemblance to N. (Nomada) idahoensis and subnigro- 

 cincta. 



Nomada (Gnathias) hydrophylli n. sp. 



<^. Length 5-6. 5 mm. Black; mandible bases, labrum, broad line under 

 and behind eye below, most of clypeus and rather broad lateral face marks 

 ending at level of insertion of antennae, mesopleural patch, anterior face 

 of front coxae, sometimes two bands on propodeum, spots on sides of 

 tergites 2 and 3 and sometimes on disk of 6, yellow; clypeus above, supra- 

 clypeus, orbital lines from end of yellow lateral face marks over vertex to 

 yellow line behind eye, usually most of vertex and occiput except oval 

 ocellar spot, mesoscutum except anterior, posterior and median bands, ele- 

 vated parts of mesoscutellum and metanotum, areas surrounding the yellow 

 mesopleural and propodeal spots usually involving all of the latter, fer- 

 ruginous. Antennae red, the scape swollen and more or less black behind 

 and suffused with yellowish in front, joint 3 only one-half as long as 4, 

 joints 3-6 more or less black above. Mesoscutellum strongly bilobed. 

 Wings clear, lightly infuscated at tip, nervures and stigma yellowish 

 brown. Legs red, coxae and trochanters behind and femoral bases, es- 

 pecially behind, blackish. Abdomen dark red, basal half of tergite i black 

 and apical margins of tergites 1-4 blackish, apex deeply notched. 



Type. — Lisbon, North Dakota, June 5, 1913, on Hydrophyllunt 

 virginicum (No. 4510, O. A. Stevens), J*. 



Paratypes. — Type lot (No. 4611), i J*; type locality, June 5, 

 191 3, on Zisia aiirea (No. 4591), i J*; Fargo, North Dakota, 

 May 30, 1913, on Hydrophyllunt virginicum (No. 4449), i c^; 

 do., on Viola scabriuscula (No. 4452), i J*; do., June 14, 1914, 

 on Zizia aurea (No. 4861), i J*; do., on Hydro phyllum virgini- 

 cum (No. 4903), I J". 



The short third antennal joint, swollen scape, small size and 

 blackish-banded abdomen of this species makes it easily recogniz- 

 able. It is, however, obviously related to N. fuscicincta. 



Nomada (Nomadula) articulata Smith. 



Nomada (Nomadula) articulata dacotana (Cockerell). 



A series of six females and seven males from Omaha, Ne- 

 braska (L. T. Williams), June 11 to July 2, on Melilotus alba 



179 



