§20 NORTH AMERICAN BIRDS. 
Gznus GEOTHLYPIS Casanis. (Page 482, pl. CXVIL,, figs. 4~7.) 
Species. 
Common Cuaracters.—Above plain olive or olive-green, the head usually more 
or less different in color; beneath yellow, the anterior portions sometimes grayish 
or blackish, and belly sometimes whitish ; adult males of some species with black 
patch on sides of head. Vest on or near ground, among bushes or weeds. Eggs 
white, speckled, more or less, with brownish. 
a. Bill slender, little if any deeper than broad, its greatest. depth much less than 
half its length from nostril, the culmen only slightly or moderately curved. 
b'. Tail decidedly shorter than wing, with more than the basal half concealed 
by the coverts; first quill longer than fifth (sometimes longest); out- 
stretched feet reaching nearly (sometimes quite) to end of tail. (Sub- 
genus Oporornis BarRD.) 
c. Entire lower parts pure gamboge-yellow; forehead and sides of head 
black, with a bright yellow superciliary stripe, involving hinder as 
well as upper border of eye; feathers of crown tipped with slate- 
gray. (Sexes alike in color.) 
Adult: Above plain bright olive-green (except as described 
above), beneath continuous pure gamboge-yellow; in winter, 
similar, but gray tips to feathers on top of head more tinged 
with brown, and black on side of head somewhat obscured by 
grayish brown tips to the feathers. Young: Above olive-brown 
(including top and sides of head), the back and scapulars more 
decidedly brown; wing-coverts tipped with light tawny brown; 
wings otherwise, and tail, as in adult; beneath plain light dull 
olive, paler and more yellowish posteriorly ; no black nor yel- 
low on sides of head. Length 5.00-5.85, wing 2.55-2.80, tail 
1.90-2.20, tarsus .80-.90. West a very bulky structure of dried 
leaves, etc., lined with fine (usually black?) rootlets, on ground, 
in woods. Eggs .72 x .56, white, or creamy white, speckled or 
spotted with brown, reddish brown, and lilac-gray. Hab. East- 
.ern United States (chiefly west of Alleghanies), north to Great 
Lakes and southern New England; in winter, south to Cuba, 
and through eastern Mexico and Central America to Panama. 
677. G. formosa (Wits.). Kentucky Warbler. 
c. Only the breast, belly, and under tail-coverts pure yellow, the chin, 
throat, and chest grayish (sometimes mixed with black) in adult 
males, light grayish, dull light smoky buff, or dingy yellowish in 
adult females and immature birds; no yellow on sides of head, nor 
black on tep or sides of head, except sometimes on lores. (Sexes 
decidedly different in color.) 
