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U. S. NATIONAL MUSEUM BULLETIN 216 



PART 3 



This form shows some regional variation that parallels the differences 

 between the subspecies imitator and monticola. Specimens from the 

 East have a white spot on the seventh tergite and apex of hind femur 

 infuscate, while those from the West lack the white anal spot, and 

 often lack infuscation on the apex of hind femur, and tend toward 

 reduction of white on the flagellum and hind tarsus. Specimens from 

 the far Northwest tend to be intermediate between the eastern and 

 western varieties. If more specimens from more localities were at 

 hand, it might have been feasible to subdivide the "subspecies" 

 nigriventris or there might have been a more definite indication that 



"Tct^^ 





I 



Figure 51.- — Localities for 

 Aritranis imitator nigriven- 

 tris. 



this "subspecies" is only a color phase of both imitator and monticola, 

 with a tendency toward more northern distribution. 



Type: 9, near Estes Park, Colo., June 12, 1948, H., M., G., D., and 

 J. Townes (Washington, USNM 63761). 



Paratj^pes (11 cf, 139): From British Columbia (Bowser, Fernie, 

 and Pavilhon Lake) ; Colorado (Boulder, near Estes Park, Florissant, 

 and Sargents); New York (Saranac Lake); Northwest Territories 

 (Aklavik, Fort McPherson, near Cameron Bay on Great Bear Lake, 

 Norman Wells, and Reindeer Depot on Mackenzie Delta) ; Oregon 

 (Blitzen River in Steens Mts. at 7,000 ft.); Quebec (Alontigny); 

 Saskatchewan (Waskesiu); Wyoming (Albany Co.); and Yukon 

 (Rampart House and Wliitehorse). 



Most dates of capture are in June and July. Those outside of these 

 two months are: May 1 at Boulder, Colo.; May 29 at Bowser, B. C; 

 August 1 at Cameron Bay, Great Bear Lake, N. W. T.; and August 

 11 in Albany Co., Wyo. 



This subspecies is transcontinental in the Canadian and Hudsonian 

 zones. 



