GEOTHLYPIS. 523 
g. Smaller, and duller in color; the whole belly and 
sides buffy whitish, the bright yellow being con- 
fined to chin, throat, chest, breast, and under tail- 
coverts; black mask bordered posteriorly by a 
band (usually narrow) of light ash-gray ; length 
4.40-5.65, wing 1.90-2.20 (2.04), tail 1.85-2.20 
(2.04), exposed culmen .38-.42 (.40), tarsus .71- 
.80 (77). Nest on or near ground, supported be- 
tween weed- or coarse sedge-stalks, deeply cup- 
shaped, usually with a deep foundation of dried 
leaves. Eggs .70 x .52, white, finely speckled on 
larger end with dark brown and black, sometimes 
with a few larger spots, or “ pen-lines,” or both. 
Hab. Eastern United States (chiefly east of Alle- 
ghanies?), north to Canada and Nova Scotia; in 
winter, southern Atlantic (and Gulf?) States, Ba- 
hamas, Greater Antilles, eastern Mexico, and Cen- 
tral America, as far as Panama.... 681. G. trichas 
(84.) (ir1nn.). Maryland Yellow-throat, 
g. Larger, and brighter-colored, the lower parts entirely 
bright yellow except anal region and flanks ; black 
mask bordered posteriorly by a band (usually 
broad) of white or grayish white; yellow of 
throat, ete. richer, and olive-green of posterior 
upper parts more yellowish; length 4.75-5.85, 
wing 2.10-2.40 (2.24), tail 2.15-2.40 (2.24), ex- 
posed culmen .40-.45 (.42), tarsus .75~.83 (.80). 
West and eggs as in G. trichas, the latter averaging 
about .67 x .53. Hab. Western United States, 
east to Mississippi Valley (and Georgia?); in 
winter, more southern United States (chiefly west 
of the Mississippi) and south through western and 
central Mexico.... 68la. G. trichas occidentalis 
Brewsr. Western Yellow-throat.’ 
1 While there is no difficulty in distinguishing at a glance specimens from the region west of the Great 
Plains from those ontained along the Atlantic coast, it is a very difficult matter to refer satisfactorily specimens 
from the intermediate region. This arises from the fact that the latter are, as a rule, intermediate in character, 
occasional examples being more like one extreme than the other, as the case may be. The majority of speci- 
mens from the Mississippi Valley are more like occidentalis in the greater extent and richness of the yellow of 
the lower parts, but more like tréchas in the decided ashy tint bordering the black mask ; some, however, are not 
distinguishable in the latter respect from typical occidentalis from Arizona and other far western localities. It 
is very difficult in many cases to determine satisfactorily winter specimens, which necessarily include a large 
proportion of young birds, and on this account the winter range of the two forms as given above will probably 
require some modification. The measurements given above are in the case of trichas taken from 19 adults 
from the Atlantic coast of the United States, and for occidentalis from 18 specimens all representing localities 
west of the Great Plains. Measurements of 20 adults from the Mississippi Valley give the following results: 
