DENDROICA. 21 1 



yellow, margined with black, instead of black margined with white. 

 The heads are very differently marked. To D. dominica there is a 

 strong x'esemblance, except that the iufra-ocular crescent and eyelids 

 are yellow, not white ; the black of sides of head is much less ex- 

 tensive, and without the conspicuous white patch behind it. There 

 is much more white on the tail ; the back is streaked with black ; the 

 bill is shorter and straighter, and the size much less. 



The relationship to D. adelaidse, Baird, is much closer, however, 

 than to any other species. The proportions are rather different — 

 the wings, tail, and toes being considerably longer ; the bills pre- 

 cisely similar. The coloration and marking of the upper parts, and 

 of the head, are almost precisely the same, perhaps even to the 

 dorsal streaks, very obsoletely visible in the winter specimens of 

 adelaidse. The yellow, however, of the under parts does not ex- 

 tend beyond the jugulum, where it is abruptly defined, instead of 

 spreading over the whole under parts, excepting perhaps the crissum. 

 D. adelaidse, too, lacks the conspicuous black streaks of the sides ; 

 and the white of the outer tail feather is merely a quadrate patch in 

 the terminal half of the inner web. 



This species appears to be abundant in Arizona, not less than ten 

 specimens having been collected by Dr. Coues, though mostly in 

 very indifferent plumage, owing to the season. 



Of the four species, just referred to, the D. nigrescens is readily 

 distinguished by the black chin and throat ; the diagnostic characters 

 of the other three will be as follows : — 



Common Characters. — Upper parts ash gray, the forehead and 



sides of vertex black. A line from nostril to above eye 



(passing into white behind), chin, and throat, yellow, mar- 



' gined laterally with blackish ; crissum, inside of wings, 



axillars, and two bands on wing, white. 



Superciliary line extending to the nape, and white, except- 

 ing anterior to the eye. Cheeks black, separated from 

 the ash of the neck by a white patch. Eyelids and 

 infra-ocular crescent white. Back not streaked. Bill 

 lengthened, gonys almost concave. 



Yellow confined to jugulum ; rest of under parts 



white ; the sides streaked with black . . dominica. 

 Superciliary line scarcely extending beyond the eye, and 

 yellow, excepting at extreme end. Cheeks ashy, like 

 sides of neck ; dusky only near the eye, and not bor- 

 dered on side of neck behind by white. Eyelids and 

 infra-ocular crescent yellow. Back streaked. Bill 

 short, gonys slightly convex. 



