118 BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



Adult mnle, winter plumage. — Entirely white except for the black 

 loreal stripe through the eye and the dark clove brown tail; feathers of 

 tarsi and toes longer and denser than in summer. 



Adult fenujle, winter plumage. — Like the winter male but without the 

 black loreal stripe. 



First autumn plumage (unsexed). — Like the autumn plumage of the 

 adult but paler and huffier with some of the back feathers with concentric 

 longitudinal dusky marks ; the outer primaries more pointed and often 

 more mottled than dusky. 



Juvenal (sexes alike). — Like the adult female in summer plumage but 

 with the light brownish areas brighter and slightly more rufescent; the 

 primaries are not white, however, but dark brown mottled with tawny. 

 Females seem to have slightly more black above than males, but this 

 may be individual and not definitely sexual, as only a few specimens have 

 been seen. 



Downy young. — Like that of L. m. atkhensis but the pale areas above 

 darker, washed with pale tawny-olive ; below less yellowish, faintly tinged 

 with cinnamon-buff. 



Adult male.— Wing 179-197 (189.5); tail 101-121 (108); bill from 

 anterior end of nostril to tip 8.5-10.6 (9.6) ; width of bill at gape 11.1-13.2 

 (12.1) ; height of bill at angle of gonys 6.1-9.6 (7.6 mm.).^'^ 



Adult fcjnale.—Wing 171-190 (181.7) ; tail 89-107 (98.2) ; bill from 

 anterior end of nostril to tip 8-10 (9) ; width of bill at gape 10.5-12.2 

 (11.4) ; height of bill at angle of gonys 6.6-9.4 (7.4 mm.).^* 



Range. — Breeds in the eastern end of the Aleutian Chain (Unalaska, 

 Amaknak, Unimak, Kagamil, Chuginadak, and Umnak Islands, and the 

 mainland of Alaska south to the base of the Alaskan Peninsula and Kodiak 

 Island, Hinchinbrook Island, Dolgoi Island, and Ushagat in the Barren 

 Islands, north to Point Barrow and the Arctic Ocean; intergrades with 

 L. m. rupesfris in the interior of Alaska and northern Northwest Ter- 

 ritory. On Kodiak Island it approaches L. m. di.voni in its characters. 

 It is said to be the form of the Jamal Peninsula and the adjacent tundra 

 of northeastern Siberia, but no specimens from there have been seen. 



Winters throughout, but chiefly in the southern part of, its breeding 

 range and possibly beyond. 



Type locality. — Unalaska Island. 



Tctrao lagopiis (not of Linnaeus) Kittlitz, Denkwiind, i, 1858, 289 (Amaknak 

 Island, near Unalaska). 



" Forty-six specimens from Unalaska, Amaknak, Unimak, Kagamil, Chuginadak, 

 and Umnak Islands in the Aleutian Chain, and on the mainland of Alaska south 

 to the Alaska Peninsula and Kodiak Island, north to the Arctic Ocean. 



" Thirty-one specimens from Unalaska and Amaknak Islands, Aleutian Chain, 

 Kodiak Island, and the Alaska mainland north to Point Barrow, 



