236 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



cc. Tail averaging shorter than wing; bill smaller and less strongly uncinate, the 



exposed culmen averaging much less than 16; under parts less purely or 



uniformly white. 



d. Back, etc., darker slate-gray, the upper tail-coverts less purely or abruptly 



white or not at all whitish, the scapulars less extensively white; under 



parts less purely white; slightly smaller (wing averaging not more than 



98.2, tail not more than 97.8, in adult males). 



e. Gray of upper j^arts clearer, not passing into whitish on upper tail-coverts; 



chest never (?) with distinct undulations; tail relatively shorter (wing 



averaging 98.2, tail 94.6, in adult male). (More northern United 



States and more southern British Provinces, east of Great Plains; south 



to Louisiana, Texas, etc., in winter. ) .Lanius ludovicianus migrans (p. 243) 



ee. Gray of upper j^arts duller, usually jmssing more or less abruptly into 



whitish on iipper tail-coverts; chest often with more or less distinct 



undulations; tail relatively longer (wing averaging 98, tail 97.8, in 



adult male). (Pacific coast district, from British Columbia to Lower 



California; in winter southward through western Mexico as far as 



State of Morelos. ) Lanius ludovicianus gambeli (p. 249) 



dd. Back, etc., paler slate-gray, or approaching no. 6 gray; the upper tail-cov- 

 erts conspicuously white or whitish, the scajjulars more extensively 

 white; under parts more purely white; slightly larger (wing averaging 

 100.7, tail 99.4, in adult male). (Arid interior districts of North America, 

 from the Saskatchewan Plains and eastern British Columbia to northern 

 Mexico; southward in winter over whole of INIexico to Isthmus of 



Tehuantepec. ) Lanius ludovicianus excubitorides (p. 246) 



hb. Less white on tail, the outermost rectrix with more than the middle third 

 black, showing conspicuously beyond under tail-coverts; gray of upper parts 

 darker than in other forms, 

 c. Upper tail-coverts abruptly white or whitish; sides and flanks more faintly 

 tinged with gray; white sj^ot at base of primaries larger. 

 d. Larger, with smaller bill (adult female « averaging wing 98.5, tail 98.5, 

 exposed culmen 13.8). (Southern portion of Mexican plateau.) 



Lanius ludovicianus mexicanus (p. 248) 

 dd. Smaller, with larger bill (adult female averaging wing 94.3, tail 94.7, 

 exposed culmen 15.7). (San Clemen te Island, southern California, and 

 Santa Margarita Island, Lower California). 



Lanius ludovicianus mearnsi (p. 252) 



cc. Upper tail-coverts concolor with back; sides and flanks deep gray (no. 6); 



white spot at base of primaries much smaller. (Santa Cruz Island, 



southern California. ) Lanius ludovicianus anthonyi (p. 251) 



In addition to the forms mentioned in the '"key" two other species 

 for a long time passed current as North American, but have since 

 proven to be well-lvnown Palwarctic species. These are the following: 



(1) Lanius elegans Swainson (=Lanius lahtora Sykes). 



Lanius elegans Swainson, Fauna Bor.-Am., ii, 1831, 122 (" Fur Countries;" type 

 in coll. Brit. Mus.).— Nuttall, Man. Orn. U. S. and Can., 2d ed., 1840, i, 

 287. — Baird, in Stansbury's Eep. Gt. Salt Lake, 1852, 328; Rep. Pacific 

 R. R. Surv., ix, 1858, 324, footnote (excl. syn. part). — Bonaparte, Rev. 

 et Mag. de Zool., 1853, 295.— Coues, Birds Col. Val., 1878, 545. 



« Measurements of adult females only are given of these three dark-colored forms, 

 for the reason that I have not been able to examine males of L. I. mearnsi and L. I. 

 anthonyi. 



