Studies of North American Bees lOi 



Subgenus Nomadula Cockerell, 1903 



KEY TO THE NEBRASKA SPECIES 



Females 



Mesoscutum and propodeum paler red without a median dark band ; fla- 

 gellum and legs wholly red; 7-8 mm scita 



Mesoscutum and propodeum darker red with a median black band ; fla- 

 gellum dusky above beyond third antennal joint; hind femora 

 blackish behind; 7-10 mm articulata and a. dacotana 



Males 



Hind femora red, only slightly suffused with blackish behind if at all ; 

 base of abdomen black, the yellow bands well formed on ter- 

 gites I and 2, narrowly interrupted or complete ; collar, 

 tubercles and tegulae yellow, mesoscutellum black or with yellow 

 spots; joint 3 of antennae very oblique at apex; 7-8 mm. 



sciia 



Hind femora black behind ; base of abdomen largely red, the yellow bands 



usually broadly interrupted, that on i frequently reduced to 



lateral spots or obsolete ; collar black, tubercles, tegulae and 



mesoscutellum red ; joint 3 of antennae less oblique at apex . . . i 



I. Mesoscutum black without any red, the abdomen less extensively 



red ; 7-7.5 mm articulata 



I. Mesoscutum largely or partly red with a broad median black band, 

 the abdomen more extensively red; 7-9.5 mm. 



articulata dacotana 

 Nomada (Nomadula) articulata Smith. 



1837. Nomada bisigiiata var. Say, Boston Journal Nat. Hist., I, p. 403, 



d*. 

 1854. Nomada articulata Smith, Cat. Hymenopterous Ins. British Mus., 



n, p. 248, c?. 



1854. Nomada annulata Smith, ibid., pp. 248-49, ^ (not ?). 



1863. Nomada articulata Cresson, Proc. Ent. Soc. Phil, 11, pp. 297. 



99, d*. 

 1863. Nomada iiiccrfa Cresson, ibid., pp. 309-10, $. 

 1903. Centrias americana Robertson, Can. Ent., XXXV, p. 176, $ (^ 



(not N. americana Kirby). 

 1903. Nomada americana Cockerell, Proc. Acad. Nat. Sci. Phil., p. 590 



(not N. ajnericana Kirby). 

 1905. Nomada (Nomadula) articulata Cockerell, Trans. Am. Ent. 



Soc, XXXI, p. 312, c^. 



The typical form of Nomada articulata occurs only in eastern 



lOI 



