BIRDS OP NORTH AND MIDDLE AMERICA. 257 



ings). Eggs 3-8, light bluish or greenish (more rarely whitish) more 

 or less thickly speckled with brown or olive. 



Range. — Nearly cosmopolitan (absent only in Lesser Antilles, Cen- 

 tral and South America, Madagascar, New Zealand, and part of 

 Polynesia). 



Three of the five West Indian species ((7. jwinalcenfiin, O. rtosiciis, 

 and C. leucognaphahii) seem very distinct in their exposed nostrils, 

 semierect nasal plumes, large naked postocular space, and more com- 

 pressed bill, but the other two {O. soUiarius and C. minutus) are 

 intermediate in these characters between the above-mentioned forms 

 and the continental type, or exhibit a combination of their char- 

 acters. Consequently, 1 am obliged to consider the generic name 

 Microcorax, Sharpe, a synonym of Corcua. 



KEY TO THE SPECIES AND SUBSPECIES OF COKVUS. 



a. Feathers of throat elongated, lanceolate, distinctly outlined. (Ravens.) ♦ 



6. Feathers of neck, upper back, and breast gray basally. ( Cmvui corax. ) 



c. Eighth (third from outside) primary usually longer than sixth, sometimes 

 longer than seventh. 

 d. Larger, with stouter bill and relatively shorter and thicker tarsi (adult 

 male with exposed culmen averaging 81.5, depth of bill at nostrils 29, 

 tarsus 68). (Northern North America, from Arctic lands to New Bruns- 

 wick, higher AUeghenies, British Columbia, etc. ) 



Corvns corax principalis (p. 259) 



dd. Smaller, with more slender bill and relatively longer and thinner tarsi 



(adult male with exposed culmen averaging 74.4, or less, depth of bill 



at nostril 25.6, or less, tarsus more than 68). 



e. Larger, with relatively larger bill (adult male averaging wing 430.8, tail 



236.7, exposed culmen 74.4, depth of bill at nostrils 25.6, tarsus 69.8). 



(Western United States and southward through Mexico to highlands 



of northern Honduras. ) Corvns corax sinuatus (p. 262) 



ee. Smaller, with relatively smaller bill (adult male averaging wing 402.6, 



tail 221, exposed culmen 68.2, depth of bill at nostrils 24.2, tarsus 68.4). 



(Eevillagigedo Islands, western Mexico, north to San Clemente and 



Santa Catalina islands, California. )... Corvns corax clarionensis (p. 264) 



cc. Eighth primary (third from outside) usually shorter than sixth, never (?) 



longer than seventh. (Commander Islands, Kamchatka.) 



Corvns corax behringianus (extralimital) « 

 hh. Feathers of neck, upper back, and breast pure white basally. (Southwestern 



United States and Mexican plateau. ) Corvns cryptoleucns (p. 265) 



aa. Feathers of throat normal (short and blended). (Grows.) 

 6. Nostrils completely hidden by antrorse nasal plumes, the latter directed forward 

 in line with longitudinal axis of maxilla. 



"•Corvus corax behringianus Dybowski, Bull. Soc. Zool. France, 1883, 263 (Bering 

 Island, Commander group, Kamchatka). — Corvus grebnitzMi Stejneger, Proc. Biol. 

 Soc. Wash., ii, 1885 (pub. Apr. 10, 1884), 97 (Bering I.; coll. U. S. Nat. Mus.). 

 The characters of this form are given in view of the possibility that it may occur as a 

 straggler in some of the westernmost Aleutian Islands. 



1038i— VOL 3—03 17 



