LEAST FLYCATCHER. 
227 
Mountains of Pennsylvania. Shores of the Missouri. Probably ranges 
over all the Middle and Western Districts. 
Male. 
“ Body rather slender. Bill smaller than the other species of the genus. 
Tarsus slightly longer than the middle toe. Second primary longest, third 
nearly equal, and rather longer than fourth, fifth one line shorter tnaa fourth, 
first intermediate between fifth and sixth. Tail emarginate and slightly 
rounded. 
“ Colour. Bill dark blackish-brown above, pale horn-colour beneath. 
Feet black. Plumage of the upper parts dark greyish-olive, crown some- 
what darker, rump lighter and inclining to greyish. A narrow ring round 
the eye greyish-white. Fore part of breast, sides, and sides of the neck 
light ash-grey, middle of throat white, rest of the lower parts very pale 
yellow or yellowish-white. Primaries and tail feathers wood-brown, the 
former narrowly, and the latter broadly edged with olive. Lower row of 
lesser wing coverts and the secondary coverts darker, tipped with dirty- 
white, that colour forming two bands across the wings. Secondaries also 
dark, like the greater wing coverts, and broadly edged with yellowish-white. 
Length 5 inches 2 lines. Extent 8 inches 3 lines. Folded wing 24 
inches. 
No perceptible difference as to colour or size between the sexes. 
“ Observations. This species will be recognized by its size, its slender 
form making it the smallest of our North American Tyrannulae. In colour 
it most resembles T. Traillii of Aud., but it is a much smaller bird, being 
nearly three-fourths of an inch shorter. T. Traillii has the breast and sides 
of the neck olivaceous ; in this species light ash-grey ; the tail also of T. 
Traillii is even. 
“ It differs from T. pusilla (comparing with the description of Swainson 
and Richardson as before) in having the wings more pointed, the second 
and third primaries being longest, and the first longer than the sixth ; while 
in pusilla the third and fourth are longest, and the first shorter than the 
sixth. The upper tail coverts of pusilla are uniform in colour with the 
back ; in our species lighter ; pusilla has the front 1 hoary in this species 
dark. The lower parts of pusilla are pale sulphur-yellow, ‘ approaching to 
siskin-geeen in our species yellowish-white ; the under mandible of pu- 
silla is yellowish-brown ; of this species horn-colour. From the figure in the 
Fauna Boreali- Americana, pusilla appears to be a stouter bird, much deeper 
in colour beneath and having a broader bill. Its smaller size, and darker 
colour above, will distinguish it from T. acadica (being two-thirds of an 
inch shorter), which species has also longer and more pointed wings, a much 
larger bill, which is light brown beneath, and an even tail.” 
