96 BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



beous-black on the interscapulars, lower back, rump, and upper tail 

 coverts; the upper tail coverts variable, sometimes barred with 

 whitish, sometimes with white spots, sometimes unbarred, uniform 

 plumbeous-black; the remiges dark plumbeous barred with dusky- 

 neutral gray, the darker bars (dusky neutral gray) narrower than the 

 lighter interspaces except on the outermost primaries where the reverse 

 is true; rectrices plumbeous-black to black with two or three narrow 

 (less than 15 mm. on median rectrices, increasing width to 30 mm., on 

 lateral (outermost) rectrices) whitish or grayish-white bars, and 

 tipped with whitish; extreme basal portion of rectrices white; chin 

 and throat white, sometimes tinged with deep gull gray; tibiae mottled 

 with slate; rest of underparts pure white; axillars black, under wing 

 coverts mixed blacldsh and grayish white; occasionally axillars and 

 under wing coverts pure wliite^^; iris dark blue-gray to blue-black; 

 cere, edge of gape, mandibular and maxillary rami, and facial skin 

 blue-gray; bill black, claws black, feet blue-gray. 



Subadult. — Similar to the adult, but with no grayish on the upper 

 throat or chin, the entire underparts immaculate white; iris reddish 

 or reddish brown; tarsi and toes yellowish as in juvenal birds. 



Juvenal (light phase). — Forehead, a broad superciliary band on each 

 side, nape, sides of head (except for a black streak immediately over 

 and behind the eye), sides of neck, anterior interscapulars, and entire 

 underparts, including the under wing and under tail coverts, creamy 

 white; crown patch, including, in some birds, the occiput as well, 

 fuscous-black to black; interscapulars, back, rump, upper wing and 

 tail coverts fuscous-black to black; the upper wing coverts and inter- 

 scapulars narrowly tipped with brownish (varying in different speci- 

 mens from pale wood brown to army brown) ; the anterior of the dark 

 interscapulars edged with whitish; the upper tail coverts basally grayish 

 and tipped with army brown; remiges (above) fuscous barred with 

 black, the black bars broad on the primaries (12-15 mm. wide) and 

 narrow on the secondaries (2.5-6 mm. wide); the fuscous areas grayish 

 below, remiges tipped with whitish; rectrices drab with three broad 

 fuscous-black or black bands, the most proximal of the three being 

 the brownest, the other two blacker; rectrices narrowly tipped with 

 whitish. 



Juvenal (dark phase). — Entire head (except bare areas as the lores 

 and eyelids), chin, throat, upper breast, lesser upper wing coverts, 

 interscapulars, and scapulars black, sometimes with a distinct gloss, 

 the lesser upper wing coverts sometimes with a fuscous tinge; rest of 

 upper wing coverts, remiges, back, rump, and upper tail coverts 

 fuscous, the middle upper wing coverts tipped with army brown; the 

 remiges tipped with avellaneous to wood brown; otherwise remiges as 



M Cf. Chubb, Birds Brit. Guiana, i, 1916, 269. 



