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U. S p. R. R. EXP. AND 5-UKVEVS — ZOOLOGY — GENERAL REPORT. 



List of specimens. 



SIALI A ARCTICA, S w a I n s o n . 



Rocky Mountain Blue Bird. 



Erijlhraca {Sialia) arciica, Swainson, F. Bor. Amer. II, 1831, 209 ; pi. x.x.ri.v. 



Erylhraca arctica, Rich. List, lt37. 



Sialia urclica, Nuttall, Man. 11, 1832, 573 ; I, 2d ed., 1840, 514.— Bonap. List, 1838.— Aim. Synopsis, 1839, 84.— 



Ib. Birds Amer. II, 1841, 178 ; pi. 13G.— McCall, Pr. A. N. Sc. V, June, 1851, 215. 

 Sylvia arctica, Audcbon, Orn. Biog. V, 1839, 38 ; pi. 373. 

 Sialia macroptera, Baird, Stansbury Report Exp. Salt Lake, 1852, 314. 



Sp. Ch. — Azure blue above and below, brightest above ; the belly and under tail covert.') white : the latter tinged with blue 

 at the ends. Female showing blue only on the rump, wings, and tail ; a white ring round the eye ; the lores and Bometimes a 

 narrow front whitish ; elsewhere replaced by brown. Length, G.25 ; wing, 4.3G ; tail, 3.00. (1875.) 



Hab. — High dry central plains ; Upper Missouri to Rocky mountains range and south to Mexico. Rare on the coast of 

 California. . , 



In this species there is none of the reddish hrown of the two otlier American bine birds, the 

 color throughout being blue, except as mentioned. The shade of blue is much lighter, with 

 more green in it, or smalts-color, especially on the crown, instead of the purplish blue of tlie 

 others. The shade on the under parts is paler than above ; it extends entirely along the sides 

 and to the abdomen. 



The female has the abdomen and under coverts like the male ; the remaining under parts, 

 with the head, neck and back, are liglit brown, althougli a bluish shade is appreciable on 



