92 BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



Range. — Arctic and cold-temperate portions of Northern Hemisphere; 

 in North America south to northern border of United States and along 

 higher part of western mountain ranges to Colorado and to northern New 

 Mexico. (Four species with many races). 



KEY TO THE NORTH AMERICAN FORMS (ADULTS) OF THE GENUS LAGOPUS 



o. Tail feathers white (Lagopits leiicurus). 



b. Bill longer and more decurved, the exposed culmen over 16 mm. in length 



(chord) (Vancouver Island) Lagopus leucurus saxatilis (p. 132) 



bb. Bill shorter and less decurved, the exposed culmen under 15 mm. in length 

 (chord). 

 c. Wing longer, averaging, in males, over 185 mm. ; in females, over 180 mm. 

 (Rocky Mountains from Montana to New Mexico). 



Lagopus leucurus altipetens (p. 134) 

 cc. Wing shorter, averaging, in male, not over 181 mm. ; in female, not over 

 170 mm. 

 d. Entire plumage white (winter plumage) : 



(northern Rocky Mountains) . . .Lagopus leucurus leucurus (p. 127) 



(Mount Rainier) Lagopus leucurus rainierensis (p. 133) 



(south-central Alaska) Lagopus leucurus peninsularis (p. 131) 



dd. Entire plumage not white. 



e. Plumage of upperparts finely vermiculated brown and gray (autumn 

 plumage). 

 /. General tone of upperparts browner — usually tawny-olive mottled 

 with gray (northern Rocky Mountains from northern Washington 



to northern Alaska) Lagopus leucurus leucurus (p. 127) 



//. General tone of plumage usually grayer — the tawny-buff being defi- 

 nitely less noticeable than the gray : 



(Amount Rainier) Lagopus leucurus rainierensis (p. 133) 



(south-central Alaska) . .Lagopus leucurus peninsularis (p. 131) 

 ee. Plumage of upperparts coarsely barred black, buff, and whitish (sum- 

 mer plumage). 

 /. Pale markings darker — pinkish buff to light pinkish cinnamon (north- 

 ern Rocky Mountains from northern Washington to Alaska). 



Lagopus leucurus leucurus (p. 127) 

 //. Pale markings paler — whitish to pale pinkish buff; only the broader 

 ones slightly darker — pinkish buff. 

 g. The dark areas deep pure black (Mount Rainier district). 



Lagopus leucurus rainierensis (p. 133) 

 gg. The dark areas black with a slight brownish tinge (so'ith-central 



Alaska) Lagopus leucurus peninsularis (p. 131) 



aa. Tail feathers black. 



b. Bill heavier, broader, and higher, its height at angle of gonys usually over 

 9.5 mm.; in winter (white) plumage with no black loreal mark {Lagopus 

 lagopus). 

 c. Shafts of primaries broadly dusky, often widening terminally ; basal half 

 of shafts of secondaries usually dusky (Newfoundland). 



Lagopus lagopus alleni (j). 108) 

 cc. Shafts of primaries whitish or narrowly dusky, dark color becoming nar- 

 rower terminally ; basal half of shafts of secondaries usually white. 

 d. Shafts of primaries usually white or nearly so (Arctic islands from 

 Baffin Island northward) Lagopus lagopus leucopterus (p. 107) 



