BIEDS OF NORTH AND MIDDLE AMEEICA. 235 



i. Coloration clearer, with white of orbital ring, etc., purer; bill 

 thicker. (Southern portion of Lower California.) 



Aimophila ruficeps sororia (p. 248) 



gg. Larger (wing averaging more than 60.96, tail averaging more than 



63.50). 



h. Larger (wing averaging 66.04, tail averaging 69.34); coloration 



paler, with more gray above. (Arizona to western Texas, 



Chihuahua and Sonora. ) Aimophila ruficeps scottii (p. 24S ) 



h. Smaller (wing averaging not more than 63.50, tail averaging less 

 than 66.04); coloration darker, with less gray above, 

 i. Paler, more rusty. (State of Oaxaca, southern Mexico.) 



Aimophila ruficeps australis (p. 250) 



a. Darker, more fuscous. (States of Guerrero, Michoacan, and 



Jalisco, southwestern Mexico. ) . Aimophila ruficeps fusoa (p. 250) 



ff. General aspect of upper parts grayish, the back with narrow brown 



streaks, often with blackish shaft-lines. 



g. Darker (hair brown above) , with streaks on back much darker. 



(Southeastern portion of Mexican plateau.) 



Aimophila ruficeps boucardi (p. 252) 

 gg. Paler (ash gray above) , with streaks on back paler. (Texas, Nuevo 



Leon, Tamaulipas, etc.) Aimopliila ruficeps eremoeca (p. 251) 



dd. Pileum brown or chestnut, streaked with grayish or dull buffy; edge of 

 wing pale yellow. 

 e. Scapulars and interscapulars with subterminal transverse spots, blotches, 

 or bars of blackish, but without mesial streaks of the same; outer webs 

 of secondaries and proximal greater coverts pale grayish brown or 

 drab. (Texasto Kansas, Arizona, and Sonora. ) . Aimopliila cassinii (p. 253) 

 ee. Scapulars and interscapulars streaked, but not subterminally spotted or 

 barred, with blackish; outer webs of secondaries and proximal greater 

 coverts more or less ruf escent. 

 /. Outermost (ninth) primary longer than third; coloration paler. 

 g. Wing averaging less than 60.96, tail averaging less than 64.77, tarsus 

 averaging less than 20.32; chestnut-brown or rusty postocular streak 

 very distinct. 

 h. Grayer above, with the chestnut streaks darker, the back always 

 and pileum usually streaked with black; chest, etc. , more grayish. 

 (Lower Georgia to Florida. ) 



Aimophila aestivalis eestivalis (p. 254) 



hh. More rusty above, with chestnut streaks lighter, more rufescent, 



only the back and scapulars with black streaks, these narrower, 



sometimes wanting; chest, etc., more buffy. (South Carolina 



to Virginia, Indiana, Illinois, Texas, etc. ) 



Aimophila aestivalis bachmauii (p. 256) 

 gg. Wing averaging more than 63.50, tail averaging more than 66.04, 

 tarsus averaging more than 20.32, or else plumage very dark 

 above, with black or dusky prevailing; brown or dusky postocular 

 streak indistinct. (Southern Mexico to southern Texas and Ari- 

 zona.) Aimophila botterii botterii (p. 257) 



ff. Outermost (ninth) primary not longer than third; coloration darker 

 (otherwise like A. b. botterii, but much smaller). 

 g. Larger (adult female with wing 56.64-59.69, tail 54.10-57.91); wing- 

 coverts less brown. (East slope of Vera Cruz to Chiapas; northern 



Nicaragua?) Aimophila botterii sartorii (p. 259) 



gg. Smaller (adult female with wing 55.88, tail .53.34); wing-coverts more 

 brown. (Northeastern Guatemala. ) 



Aimophila botterii petenica (p. 260) 



