BIRDS OP NORTH AND MIDDLE AMERICA. 385 



apex forward), with a ))road superior membrane. Rictal -bristles 

 obvious but small. Wing rather long (about three and a half to three 

 and two-thirds times as long as tarsus), rather pointed (eighth to sixth 

 primaries longest, ninth shorter than sixth); primaries exceeding sec- 

 ondaries by less than length of tarsus; tertials not longer than sec- 

 ondaries. Tail about iive-sixths as long as wing {Ulaaa) to longer than 

 wing {megarJiyncha), very slightly rounded or double-rounded, about 

 half concealed by upper coverts. Tarsus rather long (about twice as 

 long as exposed culmen), stout, its scutella fairly distinct; middle toe 

 with claw about equal to tarsus; lateral claws reaching decidedly past 

 base of middle claw; hallux about equal to middle toe or a little shorter, 

 its claw about equal to the digit or shorter. 



Coloration. — Above brownish gray, brownish, or rusty, the upper 

 tail-coverts, tail, and wings usually much more rufescent than other 

 portions; the back (sometimes top of head also) sometimes streaked 

 with rusty ; lower parts white, more or less thickly marked with tri- 

 angular spots of brown, rusty, or dusky, especially on chest (where, 

 as well as on sides of throat, these spots are sometimes united into a 

 more or less conspicuous patch), the sides and flanks striped or broadly 

 streaked with the same color. Young not materially different from 

 adults. 



Range. — Northern and western North America (eastern United 

 States in winter). (Monotypic.) 



KEY TO THE SPECIES AND SUBSPECIES OF PASSBHELLA. 



a. "Wing much longer than tail, the difference not lees than 5.08; color of back gray, 

 streaked or spotted with chestnut, or else plain brown; if the latter, the color not 

 strongly contrasted with slightly more rufescent color of upper tail-coverts and 

 tail. 

 h. Difference between length of wing and length of tail greater than length of 

 exposed culmen; back distinctly streaked or spotted with chestnut. (North- 

 ern North America from eastern British provinces to coast of Bering Sea in 

 Alaska, south in winter through eastern United States. ) 



Fasserella iliaca iliaca (p. 386) 



hh. Difference between length of wing and length of tail less than length of exposed 



culmen; back not streaked nor spotted (plain brown) . 



c. Paler, the upper parts grayish brown, olive-brown, or light sepia; spots on 



chest, etc., smaller, less crowded, light sepia, warm sepia, or grayish brown. 



d. Grayer, the sides of head and neck distinctly gray, the back grayish brown; 



adult male averaging, wing 84.33, tail 74.68, exposed culmen 12.45, 



depth of bill at base 9.91, tarsus 25.65. (Shumagin Islands and Alaska 



peninsula; Unalaska?) Passerella iliaca unalaschensis (p. 389) 



dd. Browner, the sides of head and neck grayish brown, the back light sepia 



brown. 



e. Larger and paler, with larger bill; adult male averaging, wing 83.82, tail 



74.17, exposed culmen 12.70, depth of bill at base 9.65, tarsus 25.91. 



(Kadiak Island, Alaska, in summer; Middleton Island?; south in winter 



to southern California.) Passerella iliaca insularis (p. 391) 



17024—01 25 



