BIEDS OF NORTH AND MIDDLE AMEEICA. 597 



very pale rufous-buff or buffy whitish; wing 40-40.5, tail 28-29, ex- 

 posed culmen 11.5-12. (Western Panama.) 



Selasphorus ardens, adult male (p. 604). 

 ff. Middle rectrices narrowly edged with cinnamon-rufous, the inner 

 webs of lateral rectrices without rufous edging; under tail-coverts 

 light cinnamon-rufous or vinaceous-cinnamon; wing 36.5-40 (38.4), 

 tail 26.5-28.5 (27.7), exposed culmen 10-11.5 (10.5). (Costa Rica.) 

 Selasphorus simoni, adult male (p. 606). 

 cc. Throat brilliant metallic orange-red or scarlet; rectrices mostly cinnamon- 

 rufous. 

 d. Smaller (wing less than 35, tail less than 25, exposed culmen less than 12). 

 (Costa Rica and western Panama.) 



Selasphorus scintilla, adult male (p. 607). 



dd. Larger (wing more than 36), tail not less than 25, exposed culmen 15 or 



more. 



e. Back and rump metallic green; rectrices much narrower (the outermost 



much less than 2 Avide), the middle pair not notched near tip. (Pacific 



coast from British Columbia to northwestern Mexico.) 



Selasphorus alleni, adult male (p. 609). 

 ee. Back and rump cinnamon-rufous; rectrices much broader, the outer- 

 most not less than 2 wide, the middle pair notched near tip. (Western 

 North America, from Guatemala to Alaska.) 



Selasphorus rufus, adult male (p. 612). 

 hh. Pileum brilliant metallic red, like throat. (California to northwestern Mexico.) 



Selasphorus floresii," adult male (p. 616). 

 aa. Throat whiti-sh, usually flecked with dusky, sometimes with a few feathers of 

 metallic red or purple. {Adult females.) 

 b. Middle rectrices wholly metallic green or else merely edged with cinnamon- 

 rufous. 

 c. Larger (wing 45.5-52, exposed culmen 17-20); tips of lateral rectrices pure 



white Selasphorus platycercus, adult female (p. 598). 



cc. Smaller (wing 39.5^3.5, exposed culmen 11-13.5); tips of lateral rectrices 

 more or less rufescent. 



Selasphorus flammula (p. 602), Selasphorus torridus (p. 603), Selasphorus 

 ardens (p. 605), and Selasphorus simoni (p. 606), adult females. & 

 bb. Middle rectrices extensively cinnamon-rufous basally. 

 c. Smaller (wing 34-37.5, exposed culmen 11.5-12.5); tips of lateral rectrices 



cinnamon-rufous Selasphorus scintilla, adult female (p. 608). 



cc. Larger (wing 41-45, exposed culmen 17-19); tips of lateral rectrices white. 

 d. Lateral rectrices much narrower (not more than 2 mm.); wing 41-42 (41.6); 



tail, 23-26 (24.7) Selasphorus alleni, adult female (p. 610). 



dd. Lateral rectrices broader (more than 3 mm. wide); wing 43-45 (44.4); 

 tail 24.5-28 (26.4) Selasphorus rufus, adult female (p. 012). 



SELASPHORUS PLATYCERCUS (Swainson). 



BROAD-TAILED HUMMING BIRD. 



Adult maU.^AhoYe metallic bronze-green or greenish bronze; 

 middle pair of rectrices metallic bronze-green (sometimes more 

 bluish green); rest of tail dull purplish or bronzy black, the pair 



a This is imdoubtedly a hybrid between Selasphorus alleni and Cahjpte anna. 



b Before it is possible to give a key showing satisfactorily the differential characters 

 of these species, the very careful examination and comparison of a much larger num- 

 ber of specimens is necessary. 



