236 



REVIEW OF AMERICAN BIRDS. 



[part I. 



^> 



, i.; 



* ■;* 



United States — it is this section that has its highest development 

 in South and Middle America, the species being almost equally 

 numerous with the Sjloicoleae. It is a curious fact, too, that the 

 Helophagese of the United States agree with its Si'lvicoleae in the 

 wing being long and pointed, the 1st quill being always longer than 

 the 5th ; while the more southern species have the wing more 

 rounded, the 1st quill always considerably shorter than the 5th ; and 

 even in the Dendroicas of the West Indies and South America the 

 1st qull. is much shorter than in very near northern allies (as D. 

 petechia and vieilloti compared with sestiva). The only exception is 

 in Gardellina ruhrifrons of Mexico which has a pointed wing. What 

 the signification of this more imperfectly developed wing in the 

 southern members of the Sylvicolidse may be, I am at present unable 

 to state, or whether a similar condition exists in other families. 



As usual, in extensive divisions of birds, the transition from one 

 generic form to another is so gradual, through. the different species, 

 that it is very difficult to define the genera with precision, or to 

 establish trenchant characters for separating them. The following 

 synopsis, however, will be found to express the principal modifica- 

 tions of structure and characters of the group : — 



A. Wings pointed ; the Ist quill longer than the Sth ; the 3d as 

 long as or longer than the 4th. Tail nearly even, or slightly 

 rounded (the difference of the feathers less than .20) ; the 

 feathe-8 broad and firm ; the outer webs of exterior feathers 

 narrow at base^ but widening to nearly double the width 

 near the end. 



1. Bill from gape nearly as lonji: as skull, broad at base and 



much depressed ; rictal bristles reaching half way 

 from nostrils to tip. Culmen and commissure nearly 

 straight. Wings equal to the tail. Tarsi long ; toes 

 short ; middle toe without claw, about half the tarsus Setophapa. 



2. Bill from gape nearly as long as skull, broad at base, but 



deep and more Sylvicoline ; rictal bristles reaching 

 but little beyond nostrils. Culmen and commissure 

 straight to the tip. Wings longer than the almost 

 even tail. Middle toe without claw, three-fifths the 

 tarsus iJyiodiocUs. 



3. Bill from gape much shorter than head, wide at base but 



compressed and high ; the culmen and commissure 

 much carved from base, scarcely notched at tip ; 

 rictal bristles reaching nearly half way from nostrils 

 to tip. Wings about equal to the almost even tail. 

 Middle toe without claw, about three-fifths the rather 

 short tarsus ........ CurdeUiua. 



