10 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



KEY TO THE GENERA OF FORMICARIID.E.O 



a. Planta tarsi compressed and more or less sharply ridged behind, consisting of two 

 parallel rows of scutella or undivided lamina, whose line of contact forms a median 

 posterior ridge. {Formicariinx .) 

 h. Second phalanx of middle toe entirely free from outer toe; acrotarsium more or 

 less distinctly scutellate (at least on inner side). 

 c. Nostril oval or roundish, pierced directly into the completely ossified nasal 

 fossae, without trace of operculum or adjacent membrane. {Thamnophilese.) 

 d. Bill more swollen and relatively shorter and broader, its depth at frontal 

 antioe much more than one-third the length of the commissure. 

 e. Tail shorter than wing; tarsus shorter than commissure; plumage nar- 

 rowly barred, above and below Cymbilaimus (p. 18). 



ee. Tail much longer than wing; tarsus longer than commissure; plumage 

 spotted above, nearly unicolored (not barred) below. 



Hypoedaleus (extralimital).& 



dd. Bill less swollen, relatively longer and narrower, or else more compressed, 



its depth at frontal antise much less than one-third the length of 



commissure. 



e. Tail much longer than wing. 



/. Bill relatively longer (exposed culmen longer than middle toe without 



claw), much stronger, less tapering terminally, the unguis larger and 



more abruptly hooked; upper parts transversely barred; very large 



(total length 300 mm. or more) Batara (extralimital).c 



ff. Bill relatively smaller (exposed culmen not longer than middle toe 

 without claw), much weaker, more tapering terminally, the unguis 

 smaller and weaker; upper parts spotted (not barred) or immaculate; 

 smaller (total length not more than 250 mm.). 



a In order to show more clearly the relationship of the various groups, a number of 

 extralimital (South American) genera are included. My efforts have been handi- 

 capped by the lack of many species desired for comparison, among which are the 

 types of the following generic or subgeneric names: 



Neoctantes Sclater. (Type, Xenops niger Pelzeln.) 



Myrmophila Cabanis and Heine. (Type, Formicivora brevicauda Swainson.) 

 Terenura Cabanis and Heine. (Type, Myiothera maculata Maximilian.) 

 P silorhamphus Sclater. (Type, Leptorhynchus guttatus Menetries.) 

 Microbates Sclater and Salvin. (Type, Rhamphocxnus collaris Pelzeln.) 

 Myrmochanes Allen. (Type, M. hypoleucus Allen.) 

 Ehopornis Richmond. (Type, Myiothera ardesiaca Maximilian.) 

 Sclateria Oberholser. (Type, Sitta naevia Gmelin.) See footnote on p. 16. 

 Percnostola Cabanis and Heine. (Type, Lanius funehris Lichtenstein.) 

 Thamnocharis Sclater. (Type, GraUaria dignissima Sclater and Salvin.) 

 Grallaria Vieillot. (Type, Formicarius varius Boddaert.) 

 The genus Terenura, although represented in the geographic field covered by this 

 work, is necessarily omitted from the "key," because I have not been able to examine 

 a specimen of any species. (See p. 83.) 



b Hypoedaleus Cabanis and Heine, Mus. Hein., ii, Aug., 1859, 18. Type, Thamno- 

 philus guttatus Vieillot. (Southeastern Brazil; monotypic.) 



c Batara Lesson, Trait6 d'Orn., 1831, 347. Type, Vanga striata Quoy and Gaimard= 

 Thamnophilus cinereus Vieillot. — Thamnarchus Cabanis and Heine, Mus. Hein., ii, 

 1859, 19. Type, Thamnophilus cinereus Vieillot. {Batara rejected on grounds of 

 purism.) (Southeastern Brazil; monotypic.) 



