TROCHILUS. 311 



the whole, of the throat brilliant metallic (sometimes top of head similar), the 

 tail-feathers (except middle pair) without white tips ^ or green bases. Adult females 

 and young with chin and throat dull Avhitish, or pale grayish (sometimes spotted 

 centrally with the metallic color of the male), the rectrices (except middle pair) 

 greenish basally, black subterminally, and tipped with white. 



a^. Exposed culmen less than half as long as wing, the bill straight. 

 h^. Middle tail-feathers narrower near end than at base. 



c\ Exposed culmen .60, or more ; outer tail-feathers without white tips in 

 adult males. 

 d}. Outer tail-feather not decidedly shorter than middle pair, and not 

 conspicuously nai'rower than the next ; adult males with six in- 

 nermost quills abrujDtly much smaller and narrower than the 

 rest, the top of head greenish like back, or dusky, the tail- 

 feathers (except middle pair) pointed. (Subgenus Trochilus.) 

 e^ Adult male : Chin, only, opaque velvety black, the rest of the 

 gorget intense metallic crimson, changing to golden red ; 

 tail forked for about .30-.35 ; length about 3.07-3.25, wing 

 1.60, tail 1.25, exposed culmen .55-.65. Adult female : Tail 

 double-rounded, the outer feathers about as long as middle 

 pair (sometimes a little shorter), the middle pair wholly 

 green, the rest green basally, then black, the three outer 

 pairs broadly tipped with white ; length about 3.50-3.85, 

 wing 1.80, tail 1.20, culmen .70. Young male : Similar to 

 adult female, but throat streaked with dusky, feathers of 

 upper parts more or less distinctly margined with pale 

 buffy, and tail more forked. Young female: Similar to 

 young male, but throat without streaks, and tail more 

 rounded. Eggs .50 X -31. Hab. Eastern United States, 

 north to Canada, west to Great Plains, south, in winter, to 

 Cuba, eastern Mexico, and Central America, to Yeragua. 

 428. T. colubris Linn. Ruby-throated Hummingbird. 

 e^. Adult male : Chin and throat opaque velvety black, bordered 

 below by a broad band of metallic violet, changing to 

 green and blue ; tail slightly forked, or emarginated (depth 

 of fork onl}" about .10 of an inch) ; length about 3.30- 

 3.75, wing 1.70-1.75, tail 1.25, culmen .70-.75. Adidt 

 female : Tail much rounded, the middle feathers about the 

 longest ; plumage not essentially different from that of 

 female T. colubris; length about 3.90-4.10, wing 1.90-2.00, 

 tail 1.25-1.35, culmen .78-. 80. Young : Similar to adult 

 female, but feathers of upper parts margined terminally 

 with light buffy or pale rusty, the male with throat 



' Except in species of Atthis. 



