214 LANIID. 
Collyrio excubitorides, Baird, U.S. Bound. Surv. ii. Birds, p. 11°. 
Collurio excubitorides, Baird, Rev. Am. B.1. p. 445°; Sumichrast, Mem. Bost. Soc. N. H.1. p. 548”. 
Collurio ludovicianus, var. excubitorides, Baird, Brew. & Ridgw. N. Am. B. 1. p. 421"; Lawr. Bull. 
Nat. Mus. no. 4, p. 18”; Mem. Bost. Soc. N. H. ii. p. 272”. 
Lanius ludovicianus excubitorides, Coues, B. Col. Vall. i. p. 561“. 
Lanius carolinensis, Wils. Am. Orn. ii. p. 57, t. 22. f.5°; Sw. Phil. Mag. new ser.1. p. 368"; 
Licht. Preis-Verz. mex. Vég. p. 2, ef. J. f. Orn. 1863, p. 58. 
Lanius mexicanus, Brehm, J. f. Orn. 1854, pp. 145, 148°; Scl. P. Z. 8. 1859, p. 375°; Dugés, 
La Nat. i. p. 141”. 
Supra ardesiaco-cinereus, uropygio paulo pallidiore ; capitis lateribus, alis et cauda nigris ; scapularibus griseo- 
albis ; secundariorum apicibus, speculo alari, subalaribus, rectricibus quatuor gradatim lateralibus et corpore 
subtus omnino albis; rostro et pedibus nigris. Long. tota 8:0, ale 4:0, caude rectr. med. 4-2, rectr. lat. 
3:4, rostri a rictu 0°9, tarsi 1:0. (Descr. exempl. ex valley of Mexico. Mus. nostr.) 
Exempl. altera, supra grisescentior, uropygio fere albo, loris nigris supra albo indistincte limbatis. (=L. eawcu- 
bitorides, Sw., mas, ex Oaxaca, Mexico. Mus, nostr.) 
Hab. Norta America, Southern Atlantic and Gulf States® and Mississippi valley &c."4, 
Western United States and northwards to Saskatchewan ® and Canada "4, Texas 3, 
Mexican frontier §.—Mexico? 1’ 18, Charco Escondido (Couwch®), Mazatlan (Grayson, 
Forrer), Presidio (Forrer), Colima (Xantus 918), Guanajuato (Dugés °), valley of 
Mexico (White"), Tierra fria (le Strange), tableland (Bullock 1°), plateau, and 
temperate region of Vera Cruz (Sumichrast '°), Mirador (Sartorius®), Oaxaca ® 
(Loucard !°), Tehuantepec city (Sumichrast !*). 
For some time it was the practice of ornithologists to consider the Shrikes of the 
south Atlantic States and those of Western and North-western America to be separate 
species—the former bearing Linneus’s name L. ludovicianus 1, the latter that proposed 
by Swainson for a bird from the plains of the Saskatchewan, ZL. excubitorides. But 
Dr. Coues, in his ‘ Birds of the Colorado Valley,’ says that he has gradually become 
satisfied that no distinct line can be drawn between these two birds, and that the two 
alleged species grade into one another by insensible degrees !4. Other authors hold 
to these views, which we believe, so far as we can see with much more limited materials 
at our disposal for forming an opinion, to be accurately true. We therefore consider 
L. ludovicianus a variable species, with a tendency to become a dark race in the South- 
eastern States and a lighter one in the West and North-west. In Mexico both races 
occur; whether as residents or migrants we are unable to say. One of our specimens 
from the valley of Mexico seems to be in every way a typical L. ludovicianus. Our 
other Mexican specimens are more of the L. excubitorides type, but are not very constant 
in the tint of the grey of the upper surface or in the purity of the white of the rump. 
Though L. ludovicianus appears to be found throughout Mexico, it does not pass 
beyond the limits of that country. It seems to be more common on the tablelands of 
the interior; but near Mazatlan and Tehuantepec it approaches the coast, but perhaps 
only in the winter season ; for Grayson found Shrikes in the former district from October 
