378 BULLETIN 50, UNITED STATES NATIONAL MUSEUM, 



hallux slightly shorter. Wing three times as long as exposed culmen, 

 the outermost primary longest. Tail more than half as long as wing, 

 truncated or slightly double-rounded, all the rectrices very broad, 

 rounded at tip. 



Coloration. — Above metallic bronze-green, including middle rec- 

 trices, the other rectrices blackish or chestnut. Adult males with 

 forehead and chin metallic violet-blue or velvety black, a black 

 auricular stripe and white postocular stripe, the throat brilliant 

 metallic green; adult females with the forehead sooty grayish brown, 

 chin and other under parts dull whitish or buffy, the throat some- 

 times spotted with green; auricular stripe grayish brown or dusky 

 instead of black. 



Range. — Mexico (including Lower California) to Nicaragua. (Two 

 species.) 



KEY TO THE SPECIES AND SUBSPECIES OF BASILINNA. 



a. Lateral rectrices blackish (tipped with grayish in female); center of abdomen 

 white. (Basilinna leucofis.) 

 b. Bill larger (exposed culmen 14.5-18.5); green of throat more extended poste- 

 riorly, and white of abdomen more restricted. (Southern Mexico to Guate- 

 mala.) Basilinna leucotis leucoiis, adult male (p. 378). 



bb. Bill smaller (exposed culmen 14.5-15); green of throat more restricted poste- 

 riorly and white of abdomen more extended. (Northern Nicaragua.) 



Basilinna leucotis pygmsea, adult male (p. 381). 

 an. Lateral rectrices chestnut or cinnamon-rufous: abdomen light cinnamon-rufous or 

 buffy cinnamon. (Cape San Lucas district, Lower California.) 



Basilinna xantusi (p. 382). 



BASILINNA LEUCOTIS LEUCOTIS (Vieillot). 



WHITE-EARED HUMMING BIRD. 



Advlt niaJf. — Forehead, loral and malar regions, chin, and upper 

 throat rich metallic violet or violet-blue, passing into velvetj' black 

 on suborbital and auricular regions, and into duller black, faintly 

 glossed witli bluish or greenish, on crown; occiput and hindneck dark 

 metalhc bronze or bronze-green; back, scapulars, wing-coverts, and 

 rump varying from bright metallic green to bronze-green or golden 

 green, the upper tail-coverts similar but usually more bronzy (some- 

 times golden bronze), and, together with feathers of rump, more or 

 less distinctly margined with rusty; middle pair of rectrices bright 

 bronze-green, bronze, or golden bronze, the next pair similar but 

 darker, the remaining rectrices bronzy black, tipped (more or less 

 distinctly) with bright bronze or bronze-green; remig(»s purplish 

 dusky, the hmer secondaries glossed with bronze-green; a broad 

 white postocular stripe, extending backward and dowTiward above 

 and behind upper margin of auricular region to side of neck; middle 

 and lower throat brilhant metallic emerald green (more yellowish 

 green posteriorly) abruptly defined against the dark violet or violet- 



