61 <S BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



uals); maxilla dark gTayinh l)ro\vn (dull .slate color in life), mandible 

 paler (bluish white, sometimes tinged with lilac, in life); iris dark 

 bi'own; legs and feet bluish gray (in life). 



Adult male hi inmter. — -Not essentially dill'erent from the summer 

 plumage, but with rather more light cinnamon or buffy on the upper 

 parts, the feathers of pileum usually more or less edged with the 

 latter color. 



Adult female in sumnier. — Above dusk}' grayish brown or olive, 

 streaked, especially on back and along median line of pileum, with pale 

 tawny, butfy, or whitish; wings and tail grayish ])rown, with white 

 markings much more restricted than in adult males, those on tail 

 nearly if not quite obsolete; superciliar}^ stripe, chin, sides of throat, 

 and malar region whitish; chest, more or less extensively, pale ful- 

 vous, cinnamon-butt'y or yellowish l)uliy ; abdomen usually pale yellow, 

 sometimes white; sides and flanks more or less streaked with dusky, 

 the breast also sometimes narrowly streaked. 



Adult fell lide in vn liter. — Similar to the summer plumage, l)ut with 

 the bufty or cinnamoneous hues more pronounced and the broad lateral 

 crown-stripes grayish brown or olive streaked with l)lack. 



Young (JtotJi sexesf). — Similar to adult female, but superciliary and 

 malar stripes purer white, lateral crown-sti'ipes and auricular patch 

 uniform brownish l)lack, under parts paler and without yellow on 

 abdomen, and ])ack spotted rather than streaked. 



Adult 7iiale.— Length (skins), 167.64-195.58 (181.10); wing, 94.49- 

 109.22 (99.S2); tail. 70.87-85.85 (79.2.5); exposed culmen, 15.24-20.32 

 (17.53); depth of l)ill at base, 13.21-17.53 (14.99); tarsus, 20.83-25.40 

 (23.62); middle toe, 15.24-19.05 (17.58).' 



Adult female.— Length (skins), 156.21-198.12 (180.09); wing, 94.49- 

 104.65 (98.30); tail, 68.58-86.36 (76.45); exposed culmen, 15.49-19.81 

 (18.03); depth of l»ill at ])ase, 13.97-16.26 (14.73); tarsus, 22.35-25.65 

 (23.62); middle toe, 16.51-18.80 (17.53).^' 



Western United States and plateau of Mexico; north, in summer, 

 to British Columbia, Idaho, Montana, etc., east to southeastern Dakota 

 (accidentally to Michigan), eastern Nel)raska and eastern Kansas; 



breeding south to southern portion of Mexican plateau. 



* 



Guiruca vielanocephala Swainson, Philos. Ma";., new. ser., i, 1827, 438 (Temascalte- 

 pec, Mexico). — Bonaparte, Proc. Zool. Soc. Lend., 1837, 111 (Mexico) ; Geog. 

 and Comp. List, 1838, 30.— Baird, Rep. Pacific R. R. Surv., ix, 1858, 498; 

 Cat. N. Am. Birds, 1859, no. 381; Proc. Ac. Nat. Sci. Pliila., 1859, 301, 304 



' Sixty-two specimens. 



■^ Twenty-one specimens. 



As in the case of Guiraca cscrulea lazida, there is considerable geographic varia- 

 tion in measurements in this species, CaUfornia specimens being the smallest; but in 

 this case Mexican examples, instead of being the largest, are nearly as small as those 

 from California, the largest being those from the Rocky Mountain district of the 

 United States. There is a great amount of individual variation in all the measure- 



