794 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



one-fourth as long as wing, decidedly less than twice as long as mid- 

 dle toe without claw, its scutellation pycnaspidean, the acrotarsium 

 extending about two-thirds of the way across outer side, the planta 

 tarsi occupying whole posterior side and posterior third (approxi- 

 mately) of outer and inner sides, and covered with small, indistinct, 

 irregularly hexagonal scutella; basal phalanx of middle toe wholly 

 united to outer toe, about half united to inner toe; outer toe, without 

 claw, reaching only to slightly beyond second joint of middle toe, 

 the inner toe decidedly longer, reaching, without claw, to middle of 

 sub terminal phalanx of middle toe; hallux shorter than inner toe, 

 not conspicuously stouter, its claw much shorter than the digit; all 

 the claws moderately curved, sharp, and compressed. 



Coloration. — Above plain olive, the pileum dusky laterally, bright 

 yellow centrally; wings dusky, the middle and greater coverts tipped 

 with pale yellow or yellowish white, the secondaries edged with the 

 same; below pale yellow tinged with olive on chest and sides, the 

 throat light grayish. 



Nidi/ication. — (Unknown ?) 



Range. — Panama to Amazon Valley. (Monotypic.) 



KEY TO THE SUBSPECIES OF TYRANNULUS ELATUS. 



a. Darker above, with whitish wing-markings narrower; anterior under parts more 

 strongly grayish, posterior under parts paler yellow. (Cayenne.) 



Tyrannulus elatus elatus (extralimital) .« 

 aa. Paler above, with whitish wing-markings Ijroader; anterior under parts more 

 faintly grayish, posterior under parts deeper yellow. (Panama to Lower Ama- 

 zon Valley. ) Tyrannulus elatus reguloides (p. 794) 



TYRANNULUS ELATUS REGULOIDES (Ridgway). 

 RIKER'S YELLOW-CROWNED TYRANNULET. 



Similar to T. e. elatus but paler olive-green above, whitish wing- 

 markings broader, and yellow of posterior under parts deeper. 



Adults {sexes alike). — Pileum mostly blackish or dusky, passing 

 into slate color on forehead and slate-gray on superciliary region and 

 hindneck, the central portion occupied by a large, mostly concealed, 

 crown-patch of lemon or canary (sometimes slightly orange) yellow; 

 back, scapulars, rump, and upper tail-coverts plain olive-green or 

 grayish olive-green; tail deep grayish brown, narrowly tipped with 

 pale olive or dull olive-yellowish, the outer webs of rectrices edged 

 with light olive-greenish; wings dusky, the lesser coverts margined 



a [S^jlvid] elata Latham, Index Orn., ii, 1790, 549 (Cayenne; based on Le Roitelet 

 viesangc Buffon, Hist. Nat. Ois., v, 375; Mesange huppee de Cayenne Daubenton, PI. 

 Enl., pi. 708, fig. 2). — Tyrannulus elatus Vieillot, Nouv. Diet. d'Hist., xxxv, 1819, 

 94; Sclater, Cat. Birds Brit. Mus., xiv, 1888, 128, part (Oyapok, Cayenne).— ^[/ajiia] 

 data Gray. Gen. Birds, iii, 1849, p. SOb .—[Elainia] elata Gray, Hand-list, i, 1869, 356, 

 no. 5408. 



