858 BULLETIN no, ITNTTED STATER NATIONAL MUSEITM. 



Coloration. — Plain olive-green above, the pilenm sometimes grayer 

 and streaked with dusky; wings and tail dusky with yellowish olive- 

 green edgings; under parts pale yellow, passing into olive on sides, 

 the throat and chest sometimes light gray streaked with whitish. 

 Nidification. — (Unlviiown. ) 



Range. — Southern Mexico to Panama. (Two species.) 



KEY TO THE 8PECIES OP ONCOSTOMA. 



a. Throat and chest light gray, indisf inctly streaked with grayish white. (Southern 



Mexico to Panama. ) Oncostoma cinereigulare (p. 358) 



an. Throat and chest liglit olive-yellow, ol)soletely streaked with jjale ()liv(\ (Panama 

 and Oolombia.) Oncostoma olivaceum ( p. .360) 



ONCOSTOMA CINEREIGULARE (Sclater.) 

 BENT-BILLED FLYCATCHER. 



Adults (sexes alil-e). — Pileuni dull slate-gray, more or less tinged 

 with olive," the feathers darker centrally, usually forming more or less 

 distinct streaks; hindneck, back, scapulars, rump, and upper tail- 

 coverts plain olive-green; wings dusky, the lesser and middle coverts 

 margined with olive-green, the greater coverts and remiges edged 

 with olive-green, these edgings on tertials broader and more yellowish; 

 tail dusky with olive-green edgings; sides of head plain gray (nearly 

 mouse gray), the lores somewhat intermixed with whitish; cliin and 

 throat grayish white streaked wdth gray, the chest similar but gray 

 predominating; rest of under parts sidphur yellow, the sides and 

 flanks washed or obsoletely streaked with olive; axillars and under 

 wing-coverts sulphur yellow; inner web of remiges edged with 

 whitish; maxilla brownish black or dusky horn color; mandible pale 

 horn color or whitish, usually darker terminally or laterally; iris white 

 or grayish white; legs and feet flesh color '^ or ^^ellowish.'^ 



.4^7^/7^ mr/7^.— Length (skins), 81-102 (99); wing, 44.-5-53 (49); 

 tail, 31-41 (38.2); exposed culmen, 10.5-12 (10.7); tarsus, 14-J6.5 

 (14.9); middle toe, 6-8 (7.1).'^ 



^ The amount of olive tinge seems to he dependent on age or season, probably both, 

 younger birds having the pilenm dull olive-green, only slightly different from color 

 of back. 



'' Sumichrast, manuscript. 



<" "Clear yellow," Alfaro, manuscript. 



'' Twenty-two specimens. 



