14 Myron Harmon Swenk 



clypeiis black, the nlesopleura wholly black (except a small red 

 dot under each tegula), the metanotum and propodeum black 

 (except a pair of small yellow dots on the enclosure), and on 

 venter with a yellow band on sternite 2 only. From the Trouble- 

 some, Colorado, 5> it differs in the mostly red face -marks, black 

 supraclypeus, wholly red scape, yellow tegulae, black mesopleura 

 and metanotum and mostly black propodeum and black ground 

 color of tergum with the band on tergite i merely narrowly 

 interrupted. From the Corvallis, Oregon, 5) it differs in much 

 smaller size, wholly red scape, black mesopleura, and reduced 

 propodeal spots. From N. civilis spokanensis Ckll. J, it differs 

 in much smaller size, yellow tegulae, black mesopleura, yellow 

 propodeal marks, partly yellow legs without black on the tibiae, 

 and ground color of tergum black with the band on tergite i 

 merely narrowly interrupted. 



The five described varieties of N. civUis exhibit much varia- 

 tion in size, extent of erythrization, development of yellow band 

 on tergite i and color of dorsal pubescence. They may be con- 

 trasted by the following table : 



Size smaller, 7.5-9 mm. ; Rocky mountain forms. 



Mesopleura red or with a red area anteriorly; propodeal spots large 

 and not confined to enclosure. 

 Propodeal spots mostly red ; tegulae red with a yellow spot ; scape 

 in front and supraclypeus yellow; ground color of tergum mostly 

 red, the band on tergite i reduced to lateral marks ; orbital 

 margins red ; flagellum clear red ; thorax above with reddish 

 pubescence (var. a, typical, from Troublesome, Colorado, 

 June 9). 

 Propodeal spots mostly yellow ; tegulae yellow ; scape and supra- 

 clypeus red ; ground color of tergum black, the band on tergite i 

 merely narrowly interrupted ; orbital margins yellow ; flagellum 

 infuscated apically; thorax above with white pubescence (var. d, 

 from Sioux county, Nebraska, May). 

 Mesopleura black except a red subtegular dot ; propodeal spots small, 

 yellow, confined to enclosure ; tegulae yellow ; scape red ; supra- 

 clypeus black; ground color of tergum black, the band on tergite I 

 merely narrowly interrupted ; orbital margins red ; flagellum clear 

 red ; thorax above with white pubescence (var. e, from Cannon Ball, 

 North Dakota, April 15). 



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