234 Parmer, Zhe Maryland Vellow-throat. an 
yellow, others having but a trace. A female from Smith’s Island 
shows strongly the outline of the black and ashy of the male, 
especially on the forehead. In some immature fall male speci- 
mens the black and ashy is either greatly restricted or nearly 
obscured by brown tips to the feathers; in others the reverse is 
the case. The difference is doubtless caused by the former being 
from late broods, the latter from early ones. As a rule the person- 
ality of these birds is so strong that the environing influences are 
unable to allow variation except in geographical directions. 
Migration. 
The large but well rounded wing of roscoe, with its short outer 
primary, and its known winter distribution, shows that it practi- 
cally is a resident where found. It evidently entirely withdraws 
from Virginia in winter, but occurs in that season as far north at 
least as the central coast district of North Carolina. The very 
similar wing contour of true ¢vichas shows that its migratory 
journey is not extensive, probably few, if any, leaving the United 
States. The longer wing and longer outer primaries of the 
Mississippi Valley birds and their known winter home, shows 
that their journey is longer, which is also the case in a greater 
degree with the northern form érachidactyla. The following is 
interesting in this connection. A large series of summer speci- 
mens from the mountains of Western Pennsylvania were kindly 
placed at my disposal by Mr. W. E. Clyde Todd. Upon meas- 
uring them, it developed that they could readily be placed accord- 
ing to size in two groups, this being independent of altitude. 
Distributing these specimens on a map according to localities, 
it became apparent that the larger birds came from the most 
western portion of the State, the plateau region, while the group 
of smaller birds came from the mountains eastward of the divide. 
The drainage of the plateau is toward the Mississippi, while the 
mountain area is drained by streams which flow southeastward 
into the Susquehanna and then into Chesapeake Bay. It is 
apparent, therefore, that the small birds, almost typical ¢richas, 
reached their mountain summer home from the southeast by way 
of the river valleys, while the larger birds of the plateau came 
