Studies of North American Bees 43 



inner side of hind basitarsi dark golden with much black intermixed, 

 especially on the anterior edge. Abdomen dark red, tergite and sternite 

 I with black marks as described, tergite 2 with large lateral cuneate 

 yellow spots, 3 with small lateral spots, 4-6 unspotted, tergite 5 with a 

 conspicuous apical fringe of erect silvery hair, the pygidial area ^ on 6 

 broadly rounded and covered with dense long appressed hair which is 

 silvery in profile lights, some black bristles on sides of tergites 5 and 6, 

 curved on 6 apico-ventrally. Venter indistinctly punctured, the apical 

 margins of the sternites and a distinct median line on sternite 5 smooth 

 and polished. 



Allotype. — Sioux county, Nebraska, May (L. Bruner), $. 



This species is very like N. cressonii, $, but differs in the char- 

 acters given in the table. It is also obviously related to A^ sayi 

 and A^. illinoiensis but is distinctly larger and otherwise different. 

 N. cymhalariae Ckll. is related but differs in having yellow spots 

 on sides of tergite 4 and disks of 5 and 6, blackish apical margins 

 of tergites 1-4, flagellum red above, cheeks with less black, etc. 

 From N. coloradensis Ckll, it differs in smaller size, black spots 

 on face and black mesoscutal line, wholly red fourth abdominal 

 tergite, etc. 



Nomada (Nomada) cressonii Robertson. 



1863. Nomada macnlata, var. h, Cresson, Proc. Ent. Soc. Phil., II, 



p. 304, ?. 

 1893. Nomada Cressonii Robertson, Trans. Am. Ent. Soc, XX, p. 



275, 9 d*. 

 1903. Nomada Cressonii Robertson, Can. Ent., XXXV, pp. i78-79> 



1905. Nomada Crcssoni Trcvoriana Cockerel!, ibid., XXXVII, pp. 

 285 and 286, ?. 



The writer has examined two females of this species from 

 Nebraska, both from Lincoln, one collected April 18, 1903, on 

 flowers of Ribes gracile and one collected April 23, 191 1, while 

 resting on the ground under a gooseberry bush. Both of these 

 have the propodeum wholly red and the band on tergite 5 lacking. 

 A^. cressonii trci'oriana Ckll., a form described from Corvallis, 

 Oregon, and said to differ from typical cressonii by lacking the 

 subdiscal cuneate yellow spots on abdominal tergite 4, is scarcely 

 tenable even as a subspecies, since of the two Lincoln specimens 



43 



