12 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



i. Tail more graduated; larger (total length about 170 mm.); adult 



male wholly black below Othello (extralimital).« 



u. Tail less graduated; smaller (total length less than 150 mm); 

 adult males with sides and flanks white or grayish. 



Hypolophus (p. 32). 

 gg. Bill relatively much smaller and weaker (exposed culmen shorter 

 than middle toe with claw), less strongly uncinate; crest less con- 

 spicuously developed. 

 h. Tail at least four-fifths as long as wing; larger and stronger forms. 

 i. Bill larger and stouter, the exposed culmen much more than 

 half as long as tarsus. 

 j. Feathers of forehead much developed, the crest occupying 

 entire pileum; male with a white throat-patch and black 

 jugular area, the remaining under parts fulvous. 



Biatas (extralimital).^ 

 jj. Feathers of forehead short, semi-decomposed, the crest con- 

 fined to crown and occiput; adult males with under parte 

 barred with black and white, or else uniform gray or slate 

 color (rarely streaked with white). 

 k. Bill more swollen, with tip less compressed, its width at frontal 

 antise equal to its depth at same point, and equal to much 

 more than half the distance from nostril to tip of maxilla; 

 adult males conspicuously barred with black and white, 

 or gray streaked with white, beneath, females rufous above. 



Thamnophilus (p. 34). 

 kk. Bill less swollen laterally, more compressed terminally, its 

 width at frontal antiaj less than its depth at same point 

 and equal to not more than half the distance from nostril 

 to tip of maxilla; adult males plain gray, slate color, or 

 black below, females gray, olive, or brown above. 



Erionotus (p. 47). 

 a. Bill smaller and more slender, the exposed culmen not more than 

 half as long as tarsus, its depth at frontal antiae equal to not 

 more than half the distance from nostril to tip of maxilla. 



Rhopochares (extralimital).c 

 hh. Tail less than three-fourths as long as wing; smaller and weaker 



forms Dysithamnus (p. 52). 



cc. Nostril more or less narrow and longitudinal, more or less distinctly opercu- 



late, or if broadly oval or roundish the remainder of nasal fossae occupied 



by membraneous integument. 



d. Plumage softer, more lax, and semi-decomposed, especially on rump. 



(Formidvorx.) 



e. Planta tarsi distinctly scutellate, at least on inner side or posterior margin. 



a Othello Reichenbach, Av. Syst. Nat., 1850, pi. 71. Type, Lanius luctuosus Lich- 

 tenstein. (Amazon Valley; monotypic?) [I have not been able to examine T. 

 leuconotus Spix, T. aethiops Sclater, T. tschudii Pelzeln, nor T. mdanochrous Sclater 

 and Salvin, which Dr. Sclater places in the same "section" with T. luduosus.] 



& Biastes (not of Panzer, 1806) Reichenbach, Handb., 1853, 175. Type, Anabates 

 nigropedus Lafresnaye. — Biatas Cabanis and Heine, Mus. Hein., ii, Aug., 1859, 19 

 (new name for Biastes Reichenbach, preoccupied). (Southeastern Brazil ; monotypic.) 



c Rhopochares Cabanis and Heine, Mus. Hein., ii, Aug., 1859, 17. Type, Thamno- 

 philus torquatvs Swainson. (Paraguay, Uruguay, Argentina, southeastern Brazil, and 

 Bolivia; three species). 



