riCOIDES. 287 



Xo white on back nor on top of head. 



Length about 9.50-10.00, wini<; 4.85-5.25, tail 3.(50, culmen 1.40-1.60. Eggs 

 .96 X -72. JLib. Xorthorn North America, south to northern border of 

 United States, and farther on high mountain ranges, especially westward, 

 where breeding on Sierra Nevada south to at least 39°. 



400. P. arcticus (Swains.). Arctic Three-toed Woodpecker. 

 Back (especially along middle line) varied with white, ami top of head also usu- 

 ally more or less mixed with white. 

 6'. Back with detached white bars, alwaj's less in width than the black inter- 

 spaces ; white postocular streak or stripe usuallj' indistinct, black bars 

 on sides usually broader, and adult female frequently with whole top of 

 head solid black — never very conspicuously varied with white. 



Wing-coverts always uniform black; length about 9.00, wing 4.40- 

 4.60 (4.37), tail 3.10-3.75 (3.34), culmen 1.10-1.25 (1.17). Eggs .92 

 X .70. Hab. Northern North America east of Eocky Mountains; 

 south, in winter, to northern border of United States. 



401. P. americanus Brehm. American Three-toed Woodpecker. 



b'. Back with more or less confluent white bars, always broader than black 



interspaces, or else longitudinall}- blotched or striped with white; white 



postocular streak usually broader and more conspicuous; black bars on 



sides usually narrower, and adult female usually with top of head much 



varied with white. 



c'. Back usually distinctly barred with black (rarch- continuously white 



along middle line), secondaries more distinctly spotted with white 



(sometimes wing-coverts also spotted, more or less numerously, with 



white), white spots on quills larger, and female sometimes with 



white prevailing on top of head ; length about 9.50, wing 4.50-4.70 



(4.58), tail 3.10-3.7& (3.41), culmen 1.10-1.25 (1.22). Hab. Alaska, 



north of the mountains, south to Nushagak. 



401a. P. americanus alascensis (Nelson). Alaskan 

 Three-toed Woodpecker. 

 c'. Back continuoush- white along the middle line, with few if any black 

 bars, the markings being mostly longitudinal ; secondaries less dis- 

 tinctlj- spotted with white, white spots on quills smaller, wing 

 coverts never (?) spotted or speckled with white, and adult female 

 never (?) with much white streaking on top of head ; length about 

 9.50, wing 4.G5-5.00 (4.93), tail 3.20-3.65 (3.49), culmen l.l.i-1.30 

 (1.26), the bill more slender than in alascensis. Hab. Rocky Moun- 

 tains, north to Fort Liard, Fort Simpson, Fort Kenai, and Kadiak, 



south to New Mexico 4016. P. americanus dorsalis B.^irp. 



Alpine Three-toed Woodpecker. 



