448 



REVIEW OF AMERICAN BIRDS. 



[part I. 



2643S 



held, than those from the Rocky Mountains ; and among them are 



several with unusually large 

 bills, almost as large as that 

 of C. elegans, one of which 

 (No. 26,438) measures .95 

 from forehead, .55 from nostril, 

 and 1.05 from gape, which 

 generally exceeds the average. 

 The other characters, however, 

 are essttitially those of excuhi- 

 toroides. In nearly the whole 

 series (all autumnal birds) 

 there is a decided tinge of reddish on breast anti sides, which also 

 are obscurely undulated with dusky. 



Specimens from the Mississippi Yalley, east of the river, are 

 darker, with the white markings less prominent, and with a general 

 approximation to the characters of G. ludovicianus. They, are, 

 however, usually paler than the California birds. Mexican speci- 

 mens are perhaps more like those just referred to, and less typical, 

 although some are true and well-marked excuhitoroides. One of 

 these Mexican skins (No. 13,600) has an unusually slender and 

 deeply hooked bill. (See figure above.) 



In this species (?), as in G. ludovicianus, there is so much varia- 

 tion in the amount of white on the tail, as well as in the comparative 

 length of the feathers, as to unfit these features for specific indica- 

 tion, except as a general average. 



This Shrike, in its extreme stage of coloration, differs from ludo- 

 vicianus in paler and purer color ; the ash of back lighter ; the 

 under parts brilliant white, not decidedly plumbeous on the sides as 

 in the other, and without so great a tendency to the usual obsolete 

 waved lines (noticed distinctly only in winter or immature birds) ; 

 the axillars bluish-white, not plumbeous. The white of wings and 

 tail is more extended ; the hoary of forehead and whitish of scapu- 

 lars more distinct. The bristles at base of bill somewhat involving 

 the feathers are blacb, forming a narrow frontal line, not seen in the 

 other. The most striking difference is in the rump and upper tail 

 coverts, which are always appreciably and abruptly lighter than 

 the back, sometimes white or only faintly glossed with plumbeous ; 

 while in typical specimens of ludovicianus these feathers are scarcely 

 lighter at all, and generally more or less varied with blackish spots 

 at the end. The legs and tail are apparently longer, the latter less 



