374 bulletin: museum of comparative zoology. 



Type. — Adult male, no. 4033G, M. C. Z. Buchanan Bay, EUesmere 

 Land, collected June 10, 1901, by J. S. Warmbath. 



Characters. — About the size of L. kumlieni Brewster, but differing 

 in color of mantle, primaries, and having a larger and more heavy bill. 



The color of the mantle is intermediate between kumlieni and 

 argcntatus, darker than the former, lighter than the latter. 



The first primary is broadly tipped with white, the outer web black- 

 ish slate (Ridgway's Nomenclature of color), on the inner web this 

 color extends rather less than one half across the web ; second primary 

 similar only with subterminal black band and blackish slate on inner 

 web more narrow, on the outer web it does not extend as near the base 

 of the feather as on the first; third primary with white tip, blackish 

 slate on outer web less extensive, on inner web the black is limited to a 

 subterminal patch about 35 mm. long extending across web; fourth 

 primary with white tip, blackish slate on outer web extending about 

 45 mm., on inner web about 20 mm., fifth primary with white tip, 

 then subterminal blackish slate band, then narrow poorly defined bar 

 of white. 



Measurement. — Tvpe, adult male: wing, 406; tail 107; tarsus 65; 

 bill 57. 



Description of immature male taken by Joseph Dixon at Griffin 

 Point, Arctic Alaska, June 25, 1914. Orig. no. 3752. 



First primary fuscous hair-brown on outer web, lighter on inner web 

 changing to a neutral gray, with narrow whitish tip; second primary 

 similar but slightly darker on inner web, especially near tip where it 

 is as dark as outer web, and extends to outer edge; third primary 

 the same; fourth primary similar except that outer web has narrow 

 lighter edge, and inner web for the most part neutral gray; fifth 

 primary similar but no brown on inner web except a patch near the 

 tip which extends across the web. 



The tail feathers are white with subterminal patches of fuscous hair- 

 brown var^dng in size, being smaller on the outer feathers. 



The inner secondaries have light brown areas on outer webs about 

 30 mm. long, with pallid neutral gray edges. 



Mr. Warmbath found this species breeding at Buchanan Bay, 

 several sets of eggs being in Mr. Thayer's collection, 



Besides the type there are three females in the M. C. Z. collection 

 taken by Mr. Warmbath at the same locality, ahd Mr. Thayer's 

 collection contains a small series. 



Mr. Dixon took an adult female at Demarcation Point, Alaska, 

 August 28, 1913. 



