BIEDS OF NORTH AND MIDDLE AMERICA. 99 



dd. Duller ])lack, the posterior under parts blackish slate; smaller under wing- 

 coverts broadly tipped with white. (Coast district of northeastern 

 Colombia.) 



Gymnocichla nudiceps sancta-martae, adult male (extralimital).« 

 cc. Anterior margin of lesser wing-covert area broadly white; bill whitish or light 

 yellomsh. (Eastern Costa Rica to eastern Guatemala.) 



Gymnocichla chiroleuca, adult male (p. 101). 

 hh. Forehead, lores, and crown feathered. {Immature males.) f> 

 aa. General color brown above, deep tawny below. {Adult females.) 



b. Wing-coverts brown, indistinctly tipped wdth rufous-tawny. {Gymnoeichla 

 nudiceps.) 

 c. Slightly paler and smaller (wing averaging 73.6, tail 55.4, culmeu 19.7, tarsus 



29.2) Gymnocichla nudiceps nudiceps, adult female (p. 99). 



cc. Slightly darker and larger (wing averaging 75.1, tail 59.3, culmen 19.9, tarsus 



29.4 Gymnocichla nudiceps erratilis, adult female (p. 101). c 



66. Wing-coverts blackish, broadly tipped with bright tawny. 



Gymnocichla chiroleuca, adult female (p. 102). 



GYMNOCICHLA NUDICEPS NUDICEPS (Cassia). 



BARE-CROWNED ANTBIRD. 



Adult male. — Uniform black, slightly duller on rump, upper tail- 

 coverts, and posterior under parts, the latter inclining to slate-black; 

 all the wing-coverts margined terminall}^ with white, alula? and outer- 

 most primary edged with white, and rectrices (except middle pair) 

 narrowly tipped with wliite; smaller under wing-coverts uniform 

 black, the under primary coverts slate color or slate-gray, broadly 

 margined ^^^th white; inner webs of remiges broadly edged wath pale 

 gra}^ or grayish wliite; naketl sldn of head bright light blue in life; 

 bill black; iris browai; legs and feet horn color or dusky (bluish gray 

 orgra.yish blue in life?); length (skins), 143-157 (152); wing, 73.5- 

 80.5 (76.1); tail, 54-60 (57.1); culmen, 19.5-21.5 (20.6); tarsus, 

 28.5-30.5 (29.6); middle toe, lS-20.5 (18.9).^^ 



Immature male{= Myrmelastes corrinus Lawrence antl M. ceterus 

 Bangs). — vSimilar to the adult male but whole pileum feathered (only 

 the loral and orbital regions being naked) and greater wing-coverts 

 wholly dark sooty brown or sooty black (^\^tllout wliite tips). 



Adult female. — Above plain olive-brown, russet-brown or mummy 

 brown, the wings more rufescent (chestnut-brown), with tips of wing- 

 coverts (rather broadly) deep cinnamon-rufous, rufous-chestnut or 

 deep tawny; tail dark russet-brown or vandyke brown, the rectrices 

 (except middle pair) sometimes (usually?) narrowly tipped with pale 



o Gymnocichla nudiceps sancta-martee Ridgway, Proc. Biol. Soc. Wash., xxi, Oct. 20, 

 1908, 194 (Santa Marta, Colombia; coll. U. S. Nat. Mus.). 



b The different forms distinguished by same characters as those given for adult 

 males (c to cc). 



c The adult female of G. nudiceps sancta-marlse not seen by me. 



<* Eight specimens. 



