338 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



Sierra Maclre of southern Chihuahua (near Guachochi) and Durango 

 (Cerro Prieto). 



Aphelocoma grisea Nelson, Proc. Biol. Soc. Wash., xiii. May 29, 1899, 27 (near 

 Guachochi, Sierra Madre of southern Chihuahua; coll. U. S. Nat. Mus. ). 



APHELOCOMA SIEBERII SIEBERII (Wagler). 

 SIEBER'S JAY. 



Adults (sexes alike). — Above, inchiding sides of head and neck (except 

 lores), plain dull cobalt or deep azure blue, the back usually, but not 

 always, duller and grayer, sometimes distinctly so; chin and upper 

 throat very pale bluish gray or grayish white, the shafts of the feathers 

 black; the grayish white or pale grayish of upper throat gradually 

 deepening into mouse gray or smoke gray on chest, breast, and sides, 

 this gradually fading into paler gray on flanks and abdomen, the lower 

 portion of the latter, together with anal region and under tail-coverts 

 wdiite; the gray deepest on sides of breast, where more or less tinged 

 with blue (whole breast sometimes tinged with blue); bill, legs, and 

 feet black/' 



Youvg. — Pileum and sides of head deep gray, sometimes tinged 

 with blue; hindneck, sides of neck, back, scapulars, rump, and lesser 

 wing-coverts rather lighter and brownier gray; gray of under parts 

 browner, the under tail-coverts pale gray; wdngs (except smaller 

 coverts) and tail as in adults; mandible with basal half (sometimes tip 

 also) light-colored (flesh color in life), also basal half of maxillary 

 tomium. 



Adult 'wa/e. —Length (skins), 316-332.5 (326); wing, 173-188.5 (182); 

 tail, 158-169.5 (161:); exposed culmen, 27-28.5 (27.5); depth of bill at 

 nostrils, 1). 9-10. 7 (10.2); tarsus, 43-41.5 (41); middle toe, 23-25 (24).* 



Adult female.— l^Qngth (skins), 309-326.5 (318.5); wing, 174-184.5 

 (178); tail, 156.5-169.5 (162.5); exposed culmen, 28-28.5 (28); depth 

 of bill at nostrils, 10-10.5 (10.2); tarsus, 42-43.5 (43); middle toe, 2.3-25 

 (24).* 



Southern portion of Mexican plateau, in States of Vera Cruz (Jalapa, 

 Mirador, Orizaba, Cofre de Perote, etc.), Puebla (Mount Orizaba, 

 Cerro San Pedro, etc.), Mexico (north slope Volcan de Toluca), Morelos 

 (Huitzilac, Titela del Volcan), and INIichoacan (Patzcuaro, Nahuatzin, 

 etc.). 



P[ica] mherii Waglek, Syst. Av., 1827, [page 365, by count]. Pica, sp. 23. 

 G[_yanocorax] sieberii Gray, Gen. Birds, ii, 1849, 307. 



"Younger individuals, though in adult plumage, have more or less of the basal 

 portion of the mandible, sometimes the basal portion of the maxillary tomium also, 

 light colored (said to be flesh-colored in life). 



^Four specimens. 



