596 Annals of the Carnegie Museum. 



bb. Only back black or else no black except on tail, wings and head. 



c. Back black with concealed white; wing-coverts tipped with round white 

 spots; entire lower parts reddish-chestnut; size small (wing 50 mm.). 



[Formicivora boucardi virgata, 9 • 

 cc . Back not black. 



d. Upper and lower parts umber-brown, paler below; lores, narrow 

 superciliary line, chin, sides of head and rectrices, black. 



Myrmelastes immacidatus , 9 . 

 dd. Upper parts olive-brown, lower parts cinnamon-ochraceous; wings 

 and tail darker olive-brown. Cercomacra tyrannina crepera, 9 • 

 II. Tail at least half the length of the wing, usually more, but always shorter by 

 much more than the length of the hind claw. 

 a. Upper parts entirely black, slaty-black, or slate-gray mixed with black, but 

 never with olive or brownish tinge; with or without concealed white. 

 6. Under parts entirely black, slate-gray, or black and slate-gray, never 

 partially white. 

 c. Under parts deep black, like above. 



d. Whole crown bare of feathers (blue in life); white edging to wing- 

 coverts very narrow (.5 to 1 mm.). 



Gymnocichla nudiceps erralilis, $ . 

 dd. Only front of crown, from middle of eye forward, bare of feathers; 

 white edgings to coverts broader (1 to 2 mm.). 



Gymnocichla cheiroleuca, $ . 

 cc. Under parts wholly or partially slate-gray. 



d. Throat and chest black, rest below slate-gray; wing-coverts tipped 

 with white. 

 e. Size larger (wing, 73; tail, 65 mm.); upper parts deep black. 



Thamnophilus bridgesi, $ • 

 ee. Size smaller (wing, 54; tail, 38 mm.); upper parts slate-gray. 



Myrmotherula menetriesi schisticolor, $, 



dd. Entire under parts deep ashy-gray; pileum and stripe down middle 



of back black, rest above ashy-gray; wing-coverts and scapulars 



broadly edged with white. Thamnophilus ncevius atrinucha, $ . 



bb. Under parts partially or wholly white. 



c. Entirely white below, except flanks and under tail-coverts black, wing- 

 coverts tipped with white; size larger (wing, 90). 



Thamnophilus transandeanus, $ . 

 cc. Only sides and flanks white; rest below either black or slate-gray (wing, 



55). 



d. Under parts (except flanks) deep black. Myrmotherula melccna, $ . 



dd. Under parts slate-gray, blackish in middle of breast, upper parts 



slate-gray. Myrmotherula axillaris, $ (extralimital). 



aa. Upper parts (except sometimes pileum) not black, or, if black, thickly barred 



with white. 



b. Entire upper parts black, thickly barred with white, except pileum which 



is streaked (mostly concealed); lower parts white, barred with black. 



