220 Patmer, The Maryland Vellow-throat. Fe 
changes as geological influences have affected the topography, 
and, therefore, we might expect to find a great variation among 
the characters most likely to be affected. As these influences 
have acted gradually through a long series of years upon some- 
what different material, it follows that results will be different, 
according to the distances between the geographical areas exam- 
ined, because the influences are more dominant at one point than at 
some other. The forms here recognized and their values and 
distributions are as follows: 
Geothlypis trichas AND SUBSPECIES. 
Adult @ in spring: Above olivaceous brown, darker on wings and 
tail; beneath yellowish, stronger and brighter on throat, breast, and 
under tail-coverts; sides of breast olivaceous; forehead and face black, 
bordered posteriorly by ashy white; bill blackish, deeper than broad, 
tapering to a point; wings short and rounded, outer primary shorter than 
next; tail shorter than wing, well rounded; feet flesh colored; tarsus 
longer than midtoe, lateral toes nearly equal and as long as midtoe 
minus claw. 
Adult 2 in spring: Similar to male but smaller, less richly colored 
and without black; a faint loral stripe; ear-coverts darker than grayish 
face. 
Immature and winter adults: Similar to summer specimens of the 
same sex, but with the face markings less strongly defined and less exten- 
sive; coloration richer with a browner dorsum. 
The Subspectes. 
Geothlypis trichas trichas. MaryLaAnp YELLOW-THROAT. 
Turdus trichas LINN£US, Syst. Nat. ed. 12, 1776, 293. Type locality, 
Maryland. 
Adult ¢ in summer: Smallest; above olivaceous, brownish on pileum ; 
throat, breast and under tail-coverts lemon yellow; sides of breast gray- 
ish olive; facial black restricted, narrow on forehead; outer primary 
shorter than the 6th; wing, 50-54 mm.; tail, 48-52 mm.; culmen, 9-10 
mm. ; tarsus, 2I-23 mm. 
Adult 2: Smaller than @, relatively stouter bill; yellow of throat 
paler, restricted, sometimes absent. 
