BIRDS OF NORTH AND MIDDLE AMERICA. 545 



Myiobius iixvius mevius Thayer and JJancs. 15u11. Mus. ('omp. Znnl., xlvi, Jan., 



190(), 219 (Sabana de Panama). 

 Myiobius nacvius furfurosns Thaykr and Bangs, Bull. Mus. Comp. Zool., xlvi, 



Sept., 1905, 152 (Saboga I., Bay of Panama; coll. E. A. and O. Bangs). 



Genus EMPIDONAX Cabanis. 



Empidonax Cab.vnis, Journ. fiir Orn., iii, Nov., 1855, 480. (Type, Tyrannula 

 pusilla SwAiNsoN, i. e., Muscicapa Iruillii Audubon.) 



Small Tyrannidse (wiiig about 55-78 min.) with bill moderately 

 broad or rather narrow, depressed basally (its width at frontal antiag 

 decidedly less than length of gonys and not much, if any, more than 

 twice its depth at same point), tarsus more than one-fifth (sometimes 

 nearly one-thnd) as long as wmg and more than one and a half times 

 (sometimes nearly twice) as long as middle toe without claw, the 

 upper parts plain olive, olive-green, grayish brown, or brownish gray 

 (the wmgs with two pale bands, the pileum sometimes black), the 

 under parts more or less yellowish or 3^ellowish white, or buffy, shaded 

 on chest, etc., with gray, olive, brown, or ocln^aceous. 



Bill variable in relative length (usually about half as long as head), 

 moderately broad and depressed basally, its width at frontal antise 

 less than length of gonj^s and not much, if any, greater than its depth 

 at same point, narrowl}- to broadly wedge-shaped in vertical profile, 

 with lateral outlmes straight or nearly so, or (in broader-billed species) 

 faintly convex subterminally; exposed culmen shorter than middle 

 toe with claw (sometimes even shorter than toe without claw) , straight 

 to near tip where abruptly decurved, the tip of maxilla distinctly 

 uncinate; gonys much longer than mandibular rami, straight or 

 faintly convex; maxillary tomium straight, distinctly notched sub- 

 terminally. Nostril more or less (sometimes completely) exposed, 

 longitudmally oval, margmed above by narrow or moderately broad 

 membrane. Rictal bristles well developed, but slender; feathers of 

 chin and frontal antite wdth distinct bristly tips, the former recurved, 

 the latter arching over nostrils; malar apex with distinct antrorse or 

 semierect bristles. Wing moderate, rather pointed, the longest pri- 

 maries exceeding distal secondaries by at least length of middle toe 

 without claw, usually b}' about length of tarsus (by nmch more in 

 E. virescens) ; eighth, eighth and ninth, or seventh and eighth, pri- 

 maries longest, the tenth (outermost) not shorter than second, usually 

 equal to or longer than fourth, sometimes (in E. virescens) nearly as 

 long as sixth. Tail more than foiu'-fifths to very nearly as long as 

 wing, even, emarginate, slightly double-rounded, or rounded, usually 

 more or less divaricate. Tarsus more than one-fifth to nearly one- 

 third as long as wing, typically exaspidean but with a series of more 

 or less distinct longitudinal scutella on upper posterior portion of 

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