324 



U. S. p. R R. EXP. AND SURVEYS — ZOOLOGY — GENERAX REPORT. 



The following is a synopsis of the North American species : 



Common characters. — Color above bluish ash. Beneath white ; scapulars whitish along the 

 wing. A black patch from the bill through and behind the eye. A white patch at the base 

 of the primaries, and on the tijis of the secondaries. All the tail feathers, except the median, 

 tipped with white, and with a basal patch of the same. 



A. — Distinctly banded beneath. Black of eye stripe interrupted below the eye by a white 

 crescent. No black at the base of the bill above. 



Above soiled light bluish ash. Upper tail coverts, forehead, and side of crown hoary. 



C. borealis. 



B. — Uniform white (or very obsoletely banded in the young) beneath. A continuous patch 

 through the eye from the bill. A narrow frontal line of black. 



Above dark bluish slate. Forehead, sides of crown, and upper tail coverts nearly uniform 



with the back C. ludovicianus. 



Above light bluish ash. Forehead, sides of crown, and upper tail coverts, hoary white, 

 the latter sometimes glossed with ashy C. excubitoroides. 



Comparative measurements of species. 



COLLTRIO BOREALIS, Baird. 



Great Northern Shrike ; Butcher Bird. 



Lanius sepUnlrionalis, Bon. Syn. 1828, 72.— Bon. List, 18.18.— Ib. Rev. ot Mag. Zool. 1853, 294.- Niittali., Man. 



I, 1832, 258.— Ib. I. 2d cd. 1840, 285. (Not of Ginclin.) 

 Laniun borealis, Vif.ii.i.ot, Ois. Am. Sep. I, 1807,90 ; pi. 1.— Sw. F. B. Am. II, 1831, 111.— Acd. Syn. 18.39, 157.— 



In. Birds Amer. IV, 1842, 130 ; pi. 236. 

 ionius cxcubilor, Forster, Pliil.Trana. LXII, 1772, 382.— Wilson, I, 1808, 74 ; pi. v. f. 1.— Con. Obs. 1826 —Ann. 

 Orn. Biog. II, 1834, 534 ; pi. 192. 



Sp. Cii. — Above light bUiisli ash, obscurely soiled with reddish brown. Forehead, sides of tho crown, scapulars, and upper tail 

 coverts hoary white. Jiuneath white, the breast with fine transverse lines. Wings and tail black ; tho former witli a white 

 patch at base of primaries and tips of small quills ; tho latter with tho lateral feathers tipped with white. Bill bluckish brown j 

 considerably lighter at the base. Black stripe from the bill through and behind the eye, but beneath the latter interrupted by a 

 whitish crescent. Female and young with the gray soiled with brownish. Length, 9.85 ; wings, 4.50 ; tail, 4.80 ; its gradua- 

 tion .90. 



Ilab. — Northern regions from Atlantic to Pacific ; in winter south, thr<iugh must of the United States. 



Upper parts of head and body pure clear bluish ash, soiled in the slightest possible manner ; 

 changing on the rump and scapulars to ashy white ; nearly pure white on the outer edge of the 

 latter, behind. Tips of upper coverts like the back. Forehead, and a stripe from the nostrils 



