96 BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



gg. Feathers of the back not abundantly mottled or barred with dark 

 ferruginous, but more solidly blackish (Attu Island). 



Lagopus mutus evermanni, summer, female (p. 109) 

 //. Upperparts not so dark, upper back not largely blackish. Upperparts 

 fairly dark — general color sepia or darker, with or without a gray- 

 ish tone. 

 g. Brownish markings bright ochraceous-tawny (mainland of Alaska). 

 Lagopus mutus nelsoni, summer, male (p. 117) 

 gg. Brownish markings pale and much reduced in size and number (se. 



Alaska) Lagopus mutus dixoni, summer, male (p. 120) 



ee. General tone of upperparts paler — not darker than bright sayal brown 

 or tawny-olive, often with a pronounced mixture of pale ashy gray. 

 /. Upperparts very pale and ashy. 

 g. General ground color of upperparts browner — lower back and rump 

 pale tawny-olive (Atka Island). 



Lagopus mutus atkhensis, summer, male (p. 115) 

 gg. General ground color of upperparts more grayish — lower back and 

 rump Isabella color. 

 h. Lower throat and breast slightly paler — brownish feathers cin- 

 namon-buff to pale tawny-olive (Tanaga Island). 



Lagopus mutus sanfordi, summer, male (p. 113) 

 hh. Lower throat and breast slightly darker — brownish feathers cin- 

 namon-buff to very pale tawny-olive (Adak Island). 



Lagopus mutus chamberlaini, summer, male (p. 114) "* 

 //. Upperparts not so pale and not noticeably ashy. 



g. General tone of upperparts grayish — no bright tawny markings, 

 brownish markings dull and mixed with grayish. 

 h. Upperparts with many blackish blotches and with heavy blackish 

 vermiculations. 

 I. With considerable brownish in the upperparts (northern 

 Canada) . .Lagopus mutus rupestris, summer, male (p. 122) 

 a. With little or almost no brownish in the upperparts (Newfound- 

 land) Lagopus mutus welchi, summer, male (p. 126) 



hh. Upperparts with very few blackish blotches and finely vermicu- 

 lated with blackish (northern Canada). 



Lagopus mutus rupestris, autumn, male (p. 122) 

 gg. General tone of upperparts brownish — with bright tawny markings. 

 h. General tone of upperparts bright rufescent. 

 i. Throat and breast with few blackish bars or vermiculations 

 (Tanaga Island). 



Lagopus mutus sanfordi, autumn, male (p. 113) 

 it. Throat and breast with many blackish bars or vermiculations. 

 /. Upper back with many broad black bars (Amchitka) . 



Lagopus mutus gabrielsoni, autumn, male (p. 116) 

 yy. Upper back with few broad black bars (Kiska and Little 

 Kiska Islands). 



Lagopus mutus townsendi, autumn, male (p. Ill) 

 hh. General tone of upperparts not bright rufescent. 



J. Broadly barred with blackish above and on breast and upper 

 tail coverts (Amchitka). 



Lagopus mutus gabrielsoni, summer, male (p. 116) 



^ The differences between chamberlaini and sanfordi, being very small, are almost 

 impossible to express in a key. 



