DESCRIPTION OF A NEW WESTERN SUBSPECIES OF ACCiPITER 

 VELOX (WILS.) AND SUBSPECIFIC DIAGNOSIS OF A. COOPERI 

 MEXICANUS (SWAINS.). 



DV ROBERT RIDGWAY. 



--Accipiter velox rufilatus, subsp. nov. 



Subsp. Char. — Adult male with markings of lower parts paler and 

 more cinnamomcous, the thighs with cinnamon-rufous usually predom- 

 inating; adult female with markings of lower parts larger and darker 

 than in true A. velox; young (especially female) more heavily marked be- 

 neath than in true A. velox. 



Hab. — Western North America, east to Rocky Mountains, north to 

 Kodiak, south into Mexico. 



This separation is based on the careful comparison of more than 

 eighty specimens of the two forms. 



2. Accipiter cooperi mexicamis Swains. 



Accipiter mexicanus Swains. F. B. A. n, 1831, 45, foot-note (Real 

 del Monte, Mexico). 



Subsp. Char. — Adult males scarcely or at least not constantly dif- 

 ferent from those of true A. cooperi; adult females usually with mark 

 ings of lower parts denser and rather deeper in color, with more of 

 rufous on thighs; young (especially females) much more heavily marked 

 beneath, the thighs heavily spotted instead of streaked. 



Hab. — Western United States and south into Mexico. 



A careful comparison of more than sixty specimens of this species 

 shows clearly that western specimens differ from eastern examples in 

 the above-mentioned characters. 



Proceedings U. S. National Museum, vol. xi, 1833. 

 92 



