TYRANNID^ — THE FLYCATCHERS. 363 



There are few species of North American birds more difficult to distin- 

 guish than the small Flycatchers, the characters, though constant, being very 

 slight and almost inappreciable, except to a very acute observer. 



The following synopsis may aid in distinguishing the species : — 



Species and Varieties. 



A. Inner webs of secondcaries edged with pinkish-buff. 



a. Ohve-brown above, whitish beneath ; tibiae ochraceous. 



E. brunneus.' Third quill longest, first equal to seventh ; tail slightly 

 rounded. Russet-olive above, the crown, wings, and tail with a red- 

 dish-brown tinge ; a yellowisli-gray shade across the breast, and a faint 

 sulphur-yellow tinge to posterior lower parts. Wing-bands broad, 

 sharply defined, deep ochraceous ; lining of wing and tibite slightly 

 tinged with the same. Wing. 2.35 ; tail, 2.30 ; bill, .57 and .27 ; tarsus, 

 .56; middle toe, .33. Hah. Parana. 



E. axillaris.' Third quill longest, first equal to seventh ; tail ? Dark 

 grayish-brown above, nearly uniform, breast ochraceous-olive ; a just 

 appreciable tinge of sulphur-yellow on abdomen. Wing-bands narrow, 

 badly defined, in color nearly like the back ; lining of the wing and 

 tibiae very deep ochraceous. Wing, 2.40 ; tail, 2.50 ; bill, .60 and .30 ; 

 tarsus, .60 ; middle toe, .43. Hab. Orizaba. 



i. Olive-green above, yellow beneath ; tibiaj greenish. 



E. flavescens.* Third, or third and fourth quills longest; first equal to 

 eighth. Tail decidedly emarginated. Intense greenish-olive above, the 

 crown with a decided russet tinge ; beneath bright lemon-yellow, with 

 a shade of fulvous-brown across the breast. Wing, 2.35 to 2.70 ; tail, 

 2.20 to 2.40 ; bill, .59 and .30 ; tarsus, .60 ; middle toe, .35. Hah. Costa 

 Rica. 



E. bairdi.'' Fourth quill longest, first shorter than eighth. Tail slightly 

 emarginated. Dull greenish-olive above, nearly uniform ; beneath 

 clear sulphur-yellow, with a greenish-olive shade across the breast. 

 Wing, 2.60 ; tail, 2.50 ; bill, .62 and .29 ; tarsus, .65 ; middle toe, .35. 

 Hab. Eastern Mexico (Mirador). 



B. Inner webs of secondaries edged with yellowish or gr'ayish white. 

 a. Olive-green above, yellowish beneath. 



§. Young not moWed above. 



E. flaviventris. Bill broad, twice as wide as deep, and the culmen 

 less than twice the breadth. Outer web of lateral tail-feather dusky, 

 like the inner. Wing-bands narrow, whitish. Tail square. 



Clear olive-green above, sulphur-yellow beneath ; wing-bands 

 sulphur-yellowish ; lining of wing clear sulphury-yellow. Wing, 



^ E/npidonax brunneus, Ridgway. A very distinct species, not needing comparison with any 

 other. 



- Empidonax axillaris, Eidrway. 



3 Empidonax flavescens, Lawr. Maybe the southern form of bairdi, but ditler in some ap- 

 parently essential features. 



•* Empidonax bairdi, Sclateu, P. Z. S. 1858, 801 ; Ibis, 1S59, 442 ; Catal. Am. B. 1862, 

 230. — SCLATER& Salvin, Ibis, 1860, 36. {Hab. Cordova, Coban, Mazatlan, Mirador, etc.) 



