344 LEAST FLYCATCHER. 



Mountains of Pennsylvania. Shores of the Missouri. Prohably 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 than fourth, 

 first intermediate between fifth and sixth. Tail emarginate and slightly 

 rounded. 



i( 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 S inches 3 lines. Folded wing 2\ 

 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 Tyrannulse. 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. jjusilla (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 jjusilla are uniform in colour with the 

 back; in our species lighter; pusilla has the front "hoary;" in this species 

 dark. The lower parts of pusilla are pale sulphur-yellow, "approaching to 

 siskin-green;" in our species yellowish-white; the under mandible of pusilla 

 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. 



