BIRDS OF NORTH AND MIDDLE AMERICA. 263 



bb. Larger (averaging wing 65.53 or more, tail 62.23 or more), with smaller white 



spot at tip of inner web of outer tail-feather (averaging only 7.62 in length). 



c. Smaller, lighter colored, and browner; averaging wing 65.53, tail 62.23; dorsal 



region distinctly brownish. (Western Texas to Utah, Nevada, southern 



California, Lower California, and northwestern Mexico.) 



Amphispiza bilineata deserticola (p. 265) 



cc. Larger, darker colored, and more slaty; averaging wing 67.31, tail 64.77; 



dorsal region not distinctly brownish. (States of Hidalgo to Durango, 



central Mexico. ) Amphispiza bilineata grisea (p. 266) 



aa. No white superciliary stripe; sides and flanks streaked; adults with chin, throat, 

 and chest mostly white. (Amphlspiza belli. ) 

 b. Smaller (averaging wing not more than 66.55, tail 65.02); back usually obso- 

 letely streaked or without obvious streaks, 

 c. Darker; head and neck above dull slate-gray or deep mouse gray; a broad 

 stripe on each side of throat and spot on center of chest, black. (Cali- 

 fornia, including Santa Barbara Islands, and northern Lower California.) 



Amphlspiza belli belli (p. 267) 



cc. Paler; head and neck above pale smoke gray; a narrow and interrupted stripe 



on each side of throat and small spot on center of chest dull dusky grayish. 



(Ballsenas Bay, Lower California.) Amphlspiza belli cinerea (p. 269) 



bb. Larger (averaging wing 77.47, tail 72.90) ; back usually distinctly streaked with 

 dusky. (Southeastern California, western Nevada, and southeastern Oregon 

 to southern Wyoming, Colorado, and western Texas.) 



Amphlspiza belli uevadensis (p. 270) 



AMPHISPIZA BILINEATA BILINEATA (Cassin). 

 BLACK-THROATED SPARROW, 



A continuous white superciliary stripe; above plain grajdsh (more 

 brownish on back), the tail blackish with more or less of white on 

 edge and tip of outermost rectrix. 



Adults {sexes alike). — Conspicuous superciliary and malar stripes pure 

 white, the former margined above by a narrow black line, the latter 

 not I'eaching to the base of the mandible; anterior portion of the malar 

 region, together with the lores, chin, throat, and median portion of 

 chest uniform black, the last with a convex (sometimes angular) poste- 

 rior outline; rest of under parts white, shading into grayish on sides 

 and flanks, the latter, together with anal region and under tail-coverts 

 tinged more or less with buffy in winter plumage; upper parts deep, 

 slightly brownish, gray, becoming more brownish (nearly hair brown) 

 on dorsal region and wings; sides of head (between the two white 

 stripes) plain gray, like pileum; lateral tail-feather with outer web 

 chieily or wholly white, the inner web with a large terminal white spot, 

 averaging 14.73' mm. in length; second (sometimes third, rarely also 

 fourth) tail-feather with a smaller white terminal spot; maxilla, black- 

 ish; mandible, pale grayish blue with dusky tip; iris deep brown; legs 

 and feet brownish black. 



Young. — Similar to adults but without any distinct black markings 

 on head, etc. , the chin and throat white, sometimes flecked with gray- 



■^ Sometimes as much as 17.78 mm. long. 



