i89y IV ] Dwight, The Philadelphia Vireo. 2^1 
There are a few pin-point new feathers on the breast, the crown 
and the back; the ninth and eighth primaries have been replaced 
by new quills one quarter grown, the ninth slightly longer than 
the eighth, and the seventh barely shows as a minute follicle. 
Specimens taken later show the progress of the moult which is 
complete, body-feathers, wings and tail. There is considerable 
individual variation in the sequence of development of the feathers 
of the different tracts, but the development is pretty uniform on 
the whole and seems to radiate from various centres. The earliest 
new feathers appear on the breast, near the forking of the inferior 
feather-tract, and on the back in the interscapular region. The 
crown shortly begins to moult and the inner primary (the ninth 
by count) falls quickly followed by the eighth. The body 
plumage is quite rapidly renewed, the corresponding primaries of 
each wing slowly falling in pairs with their coverts so that the body 
plumage is largely renewed before the outer primaries fall. The 
wing-coverts begin to be renewed after the primaries begin to fall 
and are usually complete before the outer primaries are replaced. 
The outer members of the rows are the first to be moulted and 
this also applies to the tertiarieS which are completely renewed 
before the secondaries begin to fall. This occurs when only 
three or four of the old outer primaries remain, and the rectrices 
also fall at this stage, or a little before, beginning with the middle 
pair. The outer secondary of each wing falls first while the inner 
secondary and the alula are the last parts of the wing to be 
renewed. The renewal of the body plumage is usually very 
well under way before the moult is conspicuous in the wings, but 
the last traces of new growth are usually a few auricular and 
abdominal feathers and perhaps a few on the chin and scapular 
region. A bird of August 4 is particularly instructive. All that 
remains of the old dress are a few auricular, scapular and abdom- 
inal feathers of the body plumage, the outer pair of rectrices of the 
tail, the three outer primaries, their coverts, the alula, the five 
inner secondaries, and much of the lining of the wing. 
I have followed the moult with considerable detail because noth- 
ing has been known regarding it in this particular species, 
and it seems probable from the material I have handled that it is 
typical of all of our Vireos. 
