324 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



No other genus of jays is likely to be confounded with this, the only 

 form closely approaching Aphelocoma being the two small and aber- 

 rant species of Cyanolyca ( C. nana and C. pumilo) found in southern 

 Mexico and Guatemala. These small Cyanolycse come so very close to 

 Aphelocoma in structural characters that I am unable to discover any 

 points of material difference, but their style of coloration is very 

 distinct. 



ApheloGO'inaiB, on the other hand, closely related to Oyanocitta, from 

 which it differs chiefly in total absence of any erest. 



KEY TO THE SPECIES AND SUBSPECIES OF APHELOCOMA. 



u. Under parts chiefly light grayish or whitish. 



b. Tail longer than wings; a more or less streaked jugular and gular area, differ- 

 ent in color from breast, etc. (or else pileum, hindneck, and sides of head 

 gray, not blue), 

 c. Blue of pileum fading anteriorly and laterally into a much paler (sometimes 



whitish) hue. (Florida.) Aphelocoma cyanea (p. 326) 



rr. Blue of pileum equally intense throughout. 

 d. Sides of chest extensively uniform blue, and feathers of lower median por- 

 tion of chest blue with median spots or broad streaks of white. 

 i:. Under parts paler, the breast and sides not darker than pale brownish 

 gray. 

 /. Smaller and lighter colored (back brownish gray, blue of a dull cobalt 

 hue). {Aphelocoma califomica.) 

 !/. Blue of head, etc., darker; under parts darker. 



/t. Larger, except bill (wing of adult male averaging 128.5, tail 141, 

 exposed culmeu 26.5, tarsus 41.5); back paler gray; under parts 

 paler, with under tail-coverts usually white or but faintly tinged 

 with blue on longer feathers. ( Calif ornia, except portion south 

 of San Fernando, San Gabriel, and San Bernardino mountains 

 and north into Oregon; east slope of Sierra Nevada.) 



Aphelocoma califomica califomica (p. 327) 

 hh. Smaller, except bill (adult male averaging wing 123, tail 136, 

 exposed culmen 27.5, tarsus 40); back darker gray; under parts 

 darker, with under tail-coverts usually pale blue or strongly 

 tinged with this color. (Southern California south of San Fer- 

 nando, San Gabriel, and San Bernardino mountains; northern 



Lower California.) Aphelocoma califomica obseura (p. 330) 



gg. Blue of head, etc., paler; under parts nearly pure white. (Cape 

 district of Lower California.) 



Aphelocoma califomica hypoleuca (p. 331) 

 ff. Larger and darker colored (back deep sooty, blue of a dull ultramarine 

 hue). (Adult male averaging wing 135.5, tail 148.5, exposed culmen 

 33, tarsus 46.5. ) (Santa Cruz Island, southern California.) 



Aphelocoma iusnlaris (p. 331) 

 ee. Under parts darker, the breast and sides ash gray or light mouse gray. 

 /. Under tail-coverts grayish blue. (Rocky Mountain plateau of United 

 States, east t« Davis Mountains, Texas. ) 



Aphelocoma woodhouseii (p. 333) 

 /. Under tail-coverts white (the longer sometimes tinged with pale gray 

 or bluish at tips). (Plateau of Mexico, south to States of Hidalgo 

 and Mexico, and north to Sutton Co., Texas.) 



Aphelocoma cyaootis (p. 335) 



