Studies of North American Bees 45 



by him as N. sayi before the separation of parva is only 5 mm. 

 long and has small yellow spots on sides of tergites 2, 3 and 5, 

 those on 3 and 5 extremely vague however. It is possible that 

 both this and A'', infantida may eventually prove to be but 

 geographic races of A^ parva. It may be, also, that A'', pygmaca 

 Cresson, described from Connecticut, as well as Ashmead's de- 

 termination of that species from Colorado (Bulletin i, Colorado 

 Biological Association, p. 30), represent males belonging with 

 the parva-niinuta-infantula group of females. 



Nomada (Nomada) sayi Robertson. 



1893. Nomada sayi Robertson, Trans. Am. Ent. Soc, XX, p. 276, 



■ ?c? (part). 

 1900. Nomada sayi Robertson, Can. Ent., XXXII, pp. 293-94, ? c?- 

 1903. Nomada sayi Robertson, ibid., XXXV, pp. 178-79, ? c?. 

 1903. Nomada sayi Cockerel!, Proc. Acad. Naf. Sci. Phil., p. 605. 



Our commonest Nomada sens. str. in eastern Nebraska, occur- 

 ring west to the middle of the state and beyond southwardly. 

 Specimens are before the writer from Falls City, Nebraska City, 

 South Bend, Cedar Bluffs, Lincoln, West Point, Beaver Crossing 

 and Indianola. The species flies normally from latter April to 

 middle May, the dates varying in the Nebraska series of twelve 

 females and forty-one males from April 18 to May 17. A single 

 exceptionally late female was collected at West Point, Jtme 28, 

 on Melilotus alba. Early spring flowers are principally visited, 

 such as Primus americana, P. cerasus, Fragaria virginiana, 

 Lomatium daucifoUunv; Cochlearia armoracea, Salix nigra, 

 Ribes gracile, Viola papilionacea and Erigeron philadelphicus. 

 Our specimens agree in the main with Robertson's description of 

 the species, and are practically identical with an Illinois male 

 received from him, but they rarely have a yellow spot on the 

 sides of tergite i, while tergites 4 and 5 frequently have spots, 

 lateral on 4 and subdiscal on 5. There is also before the writer 

 a typical female collected at Ute Creek, Costilla county, Colo- 

 rado, June 24, 1907, at 9,000 feet, by H. S. Smith, and an un- 

 usually large and dark-colored female (7.5 mm.) with the third 

 submarginal narrowed to a point above, but not otherwise obvi- 



45 



