14 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 
grayish white; under parts without black, except sometimes a 
jugular area.................--- Herpsilochmus (extralimital).¢ 
hh. Rectrices 10.........-..-.------0---- Drymophila (extralimital).6 
ee. Planta tarsi entire (fused). 
f. Bill decidedly longer than head, more than one-third as long as wing. 
g. Tail four-fifths as long as wing, graduated; exposed culmen longer 
than tarsus, the latter much less than half as long as wing. 
Ramphoczenus (p. 84). 
gg. Tail but little more than half as long as wing, rounded; exposed 
culmen much shorter than tarsus, the latter nearly half as long as 
WIDP Ss oaseescee desk. v égie Je ciddeleoeeecess Microbates (p. 88). 
Jf. Bill not longer than head (usually shorter), less than one-third as long 
as wing. 
g. Rictal bristles well developed. 
h. Rectrices 10; bill much narrower and relatively deeper at base; 
tarsus longer than commissure ............-- Cercomacra (p. 90). 
hh. Rectrices 12; bill much broader and more depressed at base; 
tarsus shorter than commissure..Thamnomanes (extralimital).¢ 
gg. Rictal bristles indistinct (usually obsolete). 
h. Loral and frontal regions very densely feathered, the feathering 
erect, plush-like.............2..2..-.. Pyriglena (extralimital).¢ 
hh. Loral and frontal regions normally feathered, scantily feathered, 
or sometimes naked. ; 
i. Frontal and loral regions normally (densely) feathered. 
j. Rictal region naked, postocular region wholly feathered; larger 
forms (total length about 125 mm.), with mostly plain colora- 
TOD snot cca uesekesys seseses Myrmoborus (extralimital).¢ 
@ Herpsilochmus Cabanis, in Wiegmann’s Archiv fir Naturg., xiii, pt. i, 1847, 224. 
Type, Myiothera pileata Lichtenstein.—Dendroecia Bertoni, Aves Nuevas del Para- 
guay, 1901, 138. Type, D. erythroptera Bertoni= Myiothera rufimarginata Temminck. 
(Nearly the whole of tropical South America east of the Andes; about eleven species 
recognized, of which, however, the present writer has examined only four.) I am 
not able to find any structural characters separating Herpsilochmus from Microrhopias. 
b Formicivora (not Formicivorus Temminck, 1807) Swainson, Zool. Journ., ii, 1825, 
145. Type, Myiothera squamata Lichtenstein.—Drymophila Such (ex Swainson), Zool. 
Journ., i, Jan., 1825, 559. Type, D. variegata Such=Myjiothera ferruginea Lich- 
tenstein.—Ellipura Cabanis, in Wiegmann’s Archiv fir Naturg., xiii, pt. i, 1847, 
228. Type, Myiothera ferruginea Lichtenstein.—Stipituropsis Bertoni, Aves Nuevas 
del Paraguay, 1901, 141. Type, S. arechavalete Bertoni=Formicivora genet De 
Filippi. 
¢ Thamnomanes Cabanis, in Wiegmann’s Archiv fiir Naturg., xiii, pt. i, 1847, 230. 
Type, Lanius caesius Lichtenstein. (Colombia and Guiana to southeastern Brazil 
and upper Amazon Valley; two species.) 
@ Pyriglena Cabanis, in Wiegmann’s Archiv fiir Naturg., xiii, pt. i, 1847, 211. 
Type, Lanius domicella Lichtenstein=Turdus leucopterus Vieillot. (Ecuador and 
Peru to southeastern Brazil; five species recognized, of which the present writer 
has examined only P. leucoptera (Vieillot) and P. atra (Swainson).) 
¢ Myrmoborus Cabanis and Heine, Mus. Hein., ii, July, 1859, 9. Type, Pithys 
leucophrys Tschudi. Besides the type species, I would refer the following to this 
genus: M. myiotherinus (Spix) and M. lugubris Cabanis; probably also Hypocnemis 
schistacea Sclater and H. melanura Sclater and Salvin, and possibly H. melanopogon 
Sclater, but these three species I have not seen. 
