BLACK-THROATED G RE E N W A RB LE R. 185 



more of a dusky ash on the breast ; and in some specimens nearly 

 white. 



They no doubt pass this way on their return in autumn, for I have 

 myself shot several in that season ; but as the woods are then still 

 thick with leaves, they are much more difficult to be seen ; and make a 

 shorter stay than they do in spring. 



Species XV. SYLVIA VIRENS. 



BLACK-THROATED GREEN WARBLER. 



[Plate XVII. Fig. 3.] 



Motacilla virens, Gmel. Syst. i., p. 985. — Lefiguier dcravate noire, Buff, v., p. 298. 

 — Black-throated Green Flycatcher, Edw. t. 300. — Green Warbler, Arct. Zool. ii., 

 No. 297. — Lath. Syn. iv., p. 484, 108. — Turton, Syst. p. 607. — Parus viridis 

 gutture nigro, the Green Black-throated Flycatcher, Bartram, p. 292.* 



This is one of those transient visitors that pass through Pennsylva- 

 nia, in the latter part of April and beginning of May, on their way 

 to the north to breed. It generally frequents the high branches and 

 tops of trees, in the woods, in search of the larvse of insects that prey 

 on the opening buds. It has a few singular chirrupping notes ; and is 

 very lively and active. About the tenth of May it disappears. It is 

 rarely observed on its return in the fall, which may probably be owing 

 to the scarcity of its proper food at that season obliging it to pass with 

 greater haste ; or to the foliage, which prevents it and other passengers 

 from being so easily observed. Some few of these birds, however, remain 

 all summer in Pennsylvania, having myself shot three this season, in 

 the month of June ; but I have never yet seen their nest. 



This species is four inches and three quarters long, and seven broad ; 

 the whole back, crown and hind head is of a rich yellowish green ; front, 

 cheeks, sides of the breast, and line over the eye, yellow ; chin and throat 

 black ; sides under the wings spotted with black ; belly and vent white ; 

 wings dusky black, marked with two white bars ; bill black ; legs and 

 feet brownish yellow ; tail dusky edged with light ash ; the three exte- 

 rior feathers spotted on their inner webs with white. The female is dis- 

 tinguished by having no black on the throat. 



* Sylvia virens, Vieill. Ois. de I' Am. Sept. pi. 80. 



