280 KEY TO THE BIRDS OF EASTERN NORTH AMERICA. 
Crown, dull olive; throat, bright yellow; belly, much paler, often whitish; 
tail, brownish olive, without yellow; wing, not longer than tail; males have 
black patch on face (forehead and sides of head) which is lacking in females. 
Maryland Yellowthroat, 
Geothlypis trichas. 
See No. 522. 
Throat and belly, nearly the same color; crown, glossy black (male), or olive 
green like back (female); tail feathers, slaty brown 
faintly washed with olive on outer webs; numerous 
small black bristles at base of bill. 
Wilson’s Warbler, 
Wilson’s Blackcap. 
Sylvania pusilla. 
See No. 526. 
Entire underparts, yellow; brightest on the belly; wing, longer than tail ; 
crown, grayish; back and rump, dull olive; tail feathers, not marked with 
yellow. 
Mourning Warbler. 
Geothlypis philadelphia (young female). 
See No. 521. 
Part 5. The following species have the throat, yellow; belly, not yel- 
low ; tail feathers, marked with more or less white : — 
Back, black or dark; tail, black, with broad 
band of white; rump, yellow. 
Black and Yellow Warbler. 
Dendroica maculosa. 
See No. 500. 
Back, slaty blue, often showing yellowish olive; rump, slate color; sides of 
head, grayish or slaty blue. 
Parula Warbler. 
Blue, Yellowbacked Warbler. 
Compsothlypis americana. 
See No. 494. 
Back, dull green; throat, faintly washed with greenish yellow; rump, green; 
sides, not streaked. 
Tennessee Warbler. 
Helminthophila peregrina. 
See No. 493. 
Back, greenish; rump, greenish; cheeks, yellowish; sides, showing move or 
less dark streaks. 
Black-throated Green Warbler. 
Dendroica virens. 
