576 BULLETIN 50^ UNITED STATES NATIONAL MUSEUM. 



tip by a rather broad band of bluish black (the lateral rectrix mainly 

 the latter color), and (in unworn plumage) with a narrow terminal 

 margin of white. 



Range. — Southern Mexico to Amazon Valley. (Monotypic.) 



FLORISUGA MELLIVORA (Linnaeus). 



JACOBIN HUMMING BIRD. 



Adult male. — Head, neck, and chest uniform dark metallic blue or 

 violet-blue, becoming more greenish blue on hindneck and (some- 

 times) on lower portion of chest; a pure white bar or crescent across 

 lower part of hindneck or extreme upper back, this sometimes 

 obsolete (concealed) ; ^ back, scapulars, wing-coverts, rump, and upper 

 tail-coverts metallic green, bronze-green, or bronze; tail white, the 

 rectrices narrowly tipped (or terminally margined) and usually edged 

 (more or less) with black;'' remiges slate-blackisli, faintly glossed with 

 violaceous; breast, abdomen, flanks, and under tail-coverts immacu- 

 late pure white; sides metallic green, bronze-green, or bronze, this 

 color invading sides of breast, where sometimes extending entirely 

 across the upper portion; bill dull black; iris dark brown; feet 

 dusky; length (skins), 95-124 (118); wdng, 62-71.5 (68.4); tail, 

 32-43 (38.1); cuhnen, 16.5-22 (19.3). <^ 



Adult female. — Above metallic bronze-green or greenish bronze, 

 slightly duller or darker on pileum; tail usually more bluish green 

 (sometimes decidedly bluish), the rectrices broadly blackish sub- 

 terminally and tipped or terminally margined with white, this 

 broad and conspicuous on outermost pair but reduced to a narrow 

 edging on middle pair, the outer web of outer pair broadly edged 

 with grayish white or pale gray basally; remiges slate-blackish or 

 dusky slate, faintly glossed with violaceous; chin white (at least in 

 part) ; throat and chest with feathers dusky centrally, broadly mar- 

 gined with white (producing a scaled effect), the dark central spots 

 usually more or less glossed with metallic green or bluish green, 

 especially on chest; sides of breast and sides mottled or squamated 

 with white and bronze or bronze-greenish; median portion of breast, 

 abdomen, and flanks immaculate white; under tail-coverts dusky 

 grayish glossed with bronze-greenish basally, slightly glossy blue- 

 black subterminally, and tipped or terminally margined (broadly) 



a This white marking varies greatly in development, even in specimens from the 

 same locality; sometimes it is entirely concealed, the tips of the feathers being 

 metallic green; again it is broad and conspicuous. The "make" of the skin has 

 much to do with its apparent development, since specimens with the head crowded 

 close to the body have the white mark entirely covered or obliterated. 



b The middle rectrices, which are white, black-tipped, like the rest, are almost 

 wholly covered and hidden by the elongated upper tail-coverts. 



c Forty-six spernmens. 



