382 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



men with much more white ; rectrices blackish blue below, the lateral 

 ones with a grayish white apical spot; wing, 55-57; culmen, 14.5-15.'' 

 Nicaragua (Matagalpa). 



Basilinna leucolis (not Trochilus leucotis Vieillot) Salvin and Godman, Biol. 



Centr.-Am., Aves, ii, 1892, 312, part (Matagalpa, Nicaragua). 

 Basilinna leucotis pygmaea Simon and Hellmayr, Novit. Zool., xv, June 25. 



1908, 12 (Matagalpa, Nicaragua; coll. E. Simon). 



BASILINNA XANTUSn (Lawrence). 



XANTUS'S HUMMING BIRD. 



Differing from B. leucotis in having the tail mostly chestnut and 

 under parts vinaceous-cinnamon ; adult male with forehead, chin, 

 etc., black (sometimes faintly glossed with bluish) instead of bright 

 metallic violet or violet-blue. 



Adult male. — Forehead (sometimes crown also) loral, suborbital, 

 auricular and malar regions and chin black, the first and last some- 

 times faintly glossed with blue in certain lights; rest of upper parts 

 metalhc bronze-green, the feathers of rump and the upper tail- 

 coverts more or less distinctly margined with rusty; middle pair of 

 rectrices chestnut margined with metallic bronze-green, sometimes 

 mostly of the latter color; rest of tail chestnut, the rectrices some- 

 times margined terminally with dull bronzy; remiges purplish 

 dusky; a white or buffy white postocular stripe, followuig upper 

 and posterior margins of black auricular area to side of neck; throat 

 brilliant metallic emerald green, passing into more yellowish green 

 on chest, the feathers more or less distinctly margined (very narT 

 rowly) with dull whitish; rest of under parts vinaceous-cinnamon 

 or pale cinnamon-rufous, the breast (especially laterally) and sides 

 spotted with metallic green; femoral tufts white; bill pale brownish 

 (coral red or pinkish red in life), dusky terminally ; iris dark brown; 

 feet dusky; length (skms), 86-96 (93); wing, 50-54 (52.3); tail, 

 30-32.5 (31.1); culmen, 17-19 (17.7).^ 



Adult female. — Above similar to the adult male but forehead dull 

 brownish gray, instead of black, and rectrices (except middle pair 

 and outer web of lateral pair) with a more or less extensive blackish 

 subterminal area on each web; auricular area dusky grayish bro^v^^ 

 instead of black, the whitish postocular stripe more cinnamomeous or 

 buffy; whole under parts pale vinaceous-cmnamon or cinnamon-buff, 

 except the white femoral tufts ; maxilla wholly dusky, the mandible 

 dusky for terminal half (more or less); iris and feet as in adult male; 

 length (skms), 79-90 (84); A\dng, 43.5-52.5 (48.9); tail, 27-31 (28.7); 

 culmen, 17-19 (17.8).^ 



o Characters taken from original description. 

 & Ten specimens. 



