VIREO. 471 
@, Exposed culmen not more than .40. 
Above grayish olive-green, becoming more decidedly gray- 
ish on top of head; a whitish superciliary stripe; lower 
parts very pale sulphur-yellow, deepest on chest, the chin 
and belly white; length about 4.80, wing 2.50-2.75, tail 
1.90-2.20, exposed culmen .38-.40. Hab. Eastern North 
America, north to Manitoba and Hudson’s Bay (breeding 
chiefly north of United States) ; south, in winter, to Guate- 
mala,,Costa Rica, and Chiriqui (but not yet recorded 
either from Mexico or from any part of West Indies). 
626. V. philadelphicus (Cass.). Philadelphia Vireo. 
ce’, Wing with a well-developed spurious primary, longer than bill; exposed 
culmen much less than .50. 
d'. Top of head dull ash-gray, not distinctly different from the grayish 
olive, or olive-gray, of back. (Adult: Above olive-grayish, 
becoming more decidedly gray on top of head, more tinged 
with pale olive-greenish on rump and upper tail-coverts; a 
whitish loral streak, extending back over eye, but scarcely 
beyond it; malar region, ear-coverts, and sides of neck pale 
brownish gray or pale grayish buffy; lower parts dull white, 
more or less tinged with olive-yellowish laterally. Young: Top 
of head and hind-neck very pale grayish buff, the lores and 
superciliary region white; ear-coverts still paler buffy; back, 
scapulars, rump, and lesser wing-coverts buffy grayish; lower 
parts entirely pure white, except under tail-coverts, which are 
pale yellow; wings and tail as in adult, but greater wing- 
coverts tipped with dull grayish buffy.) 
el. Larger, with stouter bill; upper parts (especially top of head) 
averaging rather paler and clearer grayish, the flanks more 
yellowish (or less olivaceous), the colors generally clearer 
or “cleaner”; length 5.00-5.50, wing 2.65-2.95 (2.84), tail 
2.10-2.40 (2.22), bill from nostril .30-32 (.31), depth at 
base .15-.18 (.16), tarsus .68-.72 (.70). Vest in trees, usu- 
ally at a considerable height, in open copses, along banks 
of streams, or in shade-trees along streets in towns and 
cities. Eggs .75 x .55. Hab. Hastern North America, 
north to Fort Simpson and Hudson’s Bay, west to Great 
Plains ; south, in winter, to eastern Mexico. 
627. V. gilvus (VIEILL.). Warbling Vireo. 
é. Smaller, with slenderer bill; upper parts (especially top of 
head) averaging rather darker and duller grayish, flanks 
more olivaceous, the colors generally less clear ; length 4.75- 
5.40, wing 2.55-2.85 (2.69), tail 2.00-2.30 (2.14), bill from 
nostril .29-.81 (.30), depth at base .15-.16 (.15), tarsus 
.65-.70 (.68). Nest as in V. gilvus. Eggs 73 X 51. Hab, 
