BIRDS OF NORTH AND MIDDLE AMERICA, 141 



/. Smaller (wing averaging 97, tail Gl).Sialiasialissialis, adult female (p. 142) 

 //'. Larger (wing averaging 101.4; tail 64.3). 



Sialia sialis guatemalae, adult female (p. 147) 



ee. Upper parts less blui.sli, tlie dorsal region, jjileum, and hindneek hardly 



if at all tinged with blue, the l^aek more or less distinctly browner than 



pileuni Sialia sialis fulva, adult female (p. 14G) 



dd. Throat gray. {Sialia mexicana. i 



c. Larger (wing averaging more than 104, tail averaging nicjre than 63). 

 /. Back and scapulars dusky grayish brown or dull grayish blue, concolor 

 with pileum; brown of chest and sides darker, more chestnut. 



Sialia mexicana mexicana, adult female (p. 149) 



ff. Back and scapulars Ijrown, more or less strongly contij^sted with the 



grayer or bluish color of pileum and hindneek, or else {S. m. australis, 



part) wing 108 or more. 



(/. Wing longer (averaging 110.6); Ijrowu of under parts more extensive, 



usually covering whole breast, as well as chest and sides. 



Sialia mexicana australis, adult female (p. 154) 

 gg. Wing shorter (averaging less than 106); brown of under parts more 

 restricted, not covering breast, except laterally. 

 h. Averaging slightly paler in color, with longer wing and shorter ijill 

 (wing averaging 105.4; exposed culmen averaging 12.1). 



Sialia mexicana bairdi, adult female (p. 152) 

 hh. Averaging slightly darker, with shorter wing and longer bill; 

 (wing averaging 104.9; exposed culmen, 12.7). 



Sialia mexicana anabelse, adult female (p. 150) 

 ee. Smaller (wing averaging 102.9; tail averaging 62. Ij. 



Sialia mexicana occidentalis, adult female (p. 155) 

 cc. Under parts without any cinnamomeous (pale grayish brown or buffy gray, 

 passing into white on abdomen, etc.). . .Sialia arctica, adult female (p. 157) 

 (. Plumage more or less streaked. (Young.) 



b. Under parts streaked or squamated with deep brown or sooty; general color of 

 upper parts darker grayish brown or sooty. 



c. Throat white Sialia sialis and subspecies, young (p. 142) 



cc. Throat grayish Sialia mexicana and subspecies, young (p. 149) 



bb. Under parts streaked with pale In-own or grayish brown; general color of upper 

 parts much paler grayish brown ' Sialia arotica, young (p. 157) 



