Studies of North American Bees 65 



collected in the Bad Lands at the mouth of Monroe canyon, 

 Sioux county; Nebraska, June 21, 191 1, by R. W. Dawson. The 

 females agree exactly with the description of the unique type 

 female, except that sometimes there are well developed yellow 

 spots within the lateral yellow spots on the first abdominal tergite 

 and again all these spots are coalesced to form a deeply medially 

 incised but complete yellow band, that sometimes the whole 

 dypeus and supraclypeus are yellow or are strongly suffused 

 with that color, that there are usually two yellow spots of variable 

 size on the mesopleura which are sometimes large and nearly 

 coalesced, and that the basal nervure is often interstitial with 

 the transverso-medial nervure on the basad side. The five males 

 show considerable variation, as was the case in the closely related 

 elrodi. These males agree with specimens in the U. S. National 

 Museum determined as crazcfordi J* by Cockerell, especially in 

 the proportion of the antennal joints (3 = one-half of 4), the 

 truncate and feebly notched apex, the black, yellow and red 

 tribanded first abdominal tergite, the broad complete bands on 

 tergites 2-6, the small round spots on the propodeum (these 

 lacking in the Sioux county specimen), the two red or yellow 

 spots on the mesoscutellum, the yellow front of scape, lateral 

 face marks, clypeus, mandibles except tips, labrum, tubercles, 

 tegulae, collar, etc. The breadth of the lateral face marks varies 

 considerably, however, and the supraclypeal mark is sometimes 

 present and sometimes absent, so that while the face in some 

 specimens is wholly yellow beneath the level of the insertion of 

 antennae in others it has much black above the clypeus, exactly 

 parallel variations to those found in elrodi. Also, in crazvfordi 

 there is an L-shaped yellow mark of variable size, usually large, 

 below the tubercles and usually a small yellow spot behind the 

 tubercles, the metanotum usually has a red mark, and the basal 

 nervure is usually interstitial with the transverso-medial nervure. 

 Nothing in the description of N. gillettei Ckll., which the writer 

 can find, would indicate specific distinctness from crawfordi J*, 

 and it seems probable that the former is merely a color variation 

 of the latter to be matched even in the small Nebraska series. 

 Also, it would seem doubtful that N. ednae Ckll. is specifically 



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