Geographical Distribution in Birds. 459 
4, G. POLIOCEPHALA. Lee bole, ash; maxille yellow. 
Eyelids white; nape and a culars oliv ve-green ; ‘abdo- 
men whitish. Bill, 30-715 fo: wing, 2°20; tail, 2°50. 
Hab. Western Mexico (Mazatlan). 
a. poliocephala,* 
Eyelids black ; ; nape and auriculars ashy ; abdomen wholl 
yellow. Bill, ‘35, 18 deep; wing, 2°40; tail, 2°50, Had. 
Guatemala, and Costa Rica. B. caninucha.+ 
Series II. 
5. G. Pamapetruia. Head and neck wholly ashy. 
Eyeli usky; lores dusky, not in strong contrast 
th the ; black centers of the feathers of the 
ular region larger, or expanded, posteriorly, suf- 
North America, south in winter (migrating across the 
Gulf of Mexico and Caribbean Sea, without atin 
by the way !) to Costa Rica, Panama and Bogota. 
a. Philadelphia. t 
Eyelids pure white; lores deep black in strong con- 
trast with the ash; black centers of the feathers 
of the gular and jugular region, not larger 
teriorly, and showing no TB ovine to form a patch 
on the jugulum. Tail 2°25 to 2°50. (Female distin- 
| y 
eyelids, and more dusky lores.) Hab. Western prov- 
ince of North America, from British Columbia to 
Costa Rica. fi. Macegiltivra i 
In studying closely the affinities of the different forms 
in the above synopsis, one of the most striking facts noticea is is 
that all of the peculiarly southern species, except G. poliocephala, 
have the belly wholly yellow; while the most northern species 
(@. trichas), with the belly whitish in the northern form, has it 
yellow in the two southern ones; two of the tropical American 
species have also the belly whitish in their northern (G. polio- 
cephala and G. speciosa) and Aba Seta in their sues races (@. 
poliocephaia, var. coninucha, and G. speciosa var. semiflava). 
These facts we consider as ian if not ak of a fropical 
> GEOTHLYPIS POLIOCEPHALA var. POLIOCEPHALA. 
Rev. nn i, 1865, 225. 
+ GEoTHLYPIs POLIOCEPHALA 
ten Pe W eb me 1810, 101, 1. xiv.— Geothlypis 
ahaa Wi = 
Philad. Baird Bs N. Am, 1968, 296: Rev. Am. B., 1865 5, 
$ Guornize Prizaomin > why ag og ¥; 1839, 75 pl. 399. a 
a , t ga 
Paird, BON. Aaa, 1868, 494, gl. este Rev. Am. B., i, 1865, 227. 
‘ 
