BIRDS OF NORTH AND MIDDLE AMERICA. 339 



in length, slightly shorter than middle toe, tiie hallux shorter 

 than lateral toes. Wing, about three times as long as exposed cul- 

 men, the ninth (next to outermost) primary longest. Tail about 

 two-thirds as long as wing, in adult male forked and with the next 

 to outermost pair of rectrices excessively elongated, in adult female 

 double-rounded, with lateral rectrices shorter than middle pair. 

 Adult males with a conspicuous crest on each side of occiput. 



Coloration. — Adult male with top and sides of head, including 

 crests, together with tail, black; rest of plumage metallic green, 

 brighter on under parts; adult female metallic green or bronze-green 

 above (including middle rectrices), dull white beneath, spotted with 

 green laterally. 



Range. — Island of Jamaica. (Two species.) 



KEY TO THE SPECIES OF AITHURUS. 



a. Bill with at least greater part of mandible pale brownish or yellowish (red or pink 

 in life); adult male with under parts purer (less yellowish) green. (Southern 



slope of Jamaica.) Aithurus polytmus (p. 339). 



n. Bill wholly black (in both sexes); adult male with under parts more yellowish 

 green. (Northern slope of .Jamaica.) Aithurus scitulus (p. 341). 



AITHURUS POLYTMUS (Linnaeus). 



STREAMER-TAILED HUMMING BIRD. 



Adult male. — Pileum dull black or blue-black; occiput and nuchal 

 crest deep velvety black; back, scapulars, wing-coverts, rump, and 

 upper tail-coverts bright metallic green, bronze-green, or greenish 

 bronze; tail (including elongated rectrices) black, the middle pair of 

 rectrices more or less strongly glossed with bronze-green or greenish 

 bronze, the other rectrices sometimes similarly but less strongly 

 glossed, at least basally; primaries dark brownish slate or dusky, 

 glossed with purplish bronze; secondaries darker (nearly black), 

 faintly glossed with violaceous, the innermost ones with outer web 

 mostly metallic green or bronze-green; malar region, sides of neck, 

 and under parts (except under tail-coverts) luminous metallic yel- 

 lowish green (nearest apple green, but much purer in hue); under 

 tail-coverts and under surface of tail blue-black or black faintly 

 glossed with bluish; bill pale brownish or dull yellowish (pink or red 

 in life), dusky at tip; iris dark brown; feet dusky; length (skins), 

 including elongated rectrices, 211-256 (234); wing, 64.5-68.5 (66.4), 

 tail (elongated second rectrix), 152-184 (167.5); middle rectrices 

 28-32 (29.9); culmen, 20-21.5 (20.6) .« 



Immature mxde. — Similar to the adult male, but without elongated 

 rectrices; rectrices tipped with bronze-green or greenish bronze, and 

 under tail-coverts strongly glossed with greenish bronze. 



a Ten specimens. 



