236 REVIEW OF AMERICAN BIRDS. [PART 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 Sylvicolex. It is a curious fact, too, that the 
Selophagez of the United States agree with its Sylvicolex 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 quill is much shorter than in very near northern allies (as D. 
petechia and vieilloti compared with xstiva). The only exception is 
in Cardellina rubrifrons of Mexico which has a pointed wing. What 
the signification of this more imperfectly developed wing in the 
southern members of the Sylvicolidx 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 5th; 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 
feathers 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 long as skull, broad at base and 
much depressed; rictal bristles reaching half way 
from nostrils to tip. Culmen and commissure nearly 
straight. Wings equal tothe tail. Tarsi long; toes 
short ; middle toe without claw, about half the tarsus Setophaga. 
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 . . . . - - - . Myiodioctes. 
3. Bill from gape much shorter than head, wide at base but 
compressed and high; the culmen and commissure 
much curved 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. d : ; : : . Cardellina. 
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