BIRDS OF NORTH AND MIDDLE AMERICA. 15 
jj. Rictal region feathered, postocular region partly naked 
smaller forms (total length about 100 mm.) with coloration 
much variegated .............-- Hypocnemis (extralimital).¢ 
a. Frontal or loral regions, or both, scantily feathered (sometimes 
quite bare). 
j. Loral and suborbital regions (sometimes forehead and crown 
also) bare or but scantily bristled; adult males uniform black 
(with white markings on wing-coverts). 
Gymunocichla (p. 97). 
jj. Loral and suborbital regions feathered (only the postocular 
and rictal regions naked); adult males not black (or else 
without white markings on wing-coverts). 
1. Tail less than four-fifths as long as wing; bill stouter; 
nostrils smaller, more rounded; forehead more thinly 
feathered, the feathers semi-decomposed, semi-erect. 
Myrmeciza (p. 103).5 
ll. Tail more than five-sixths as long as wing (sometimes 
longer than wing); bill more slender; nostrils larger, 
more longitudinal; forehead more densely feathered, the 
feathers more compactly webbed, decumbent. 
Myrmoderas (extralimital).¢ 
dd. Plumage harder, very dense and compact, only the tail-coverts semi- 
decomposed or loose,webbed.@ (Formicariezx.) 
e. Tail less than two-thirds as long as wing; plumage of rump not abnormally 
long and dense; feathers of latero-frontal antiz short and dense, not 
antrorse, not extending above nostril; bill relatively longer and less 
depressed basally, the exposed culmen as long as middle toe without 
claw; under parts neither streaked nor barred. 
Formicarius (p. 115). 
ee. Tail more than two-thirds as long as wing; plumage of rump very long 
and dense; feathers of latero-frontal antie longer, antrorse, extending 
anteriorly, above the nostril, to anterior end of nasal fosse; bill rela- 
tively shorter and more depressed basally, the exposed culmen much 
shorter than middle toe without claw........ Chameza (extralimital).¢ 
« Hypocnemis Cabanis, in Wiegmann’s Archiv fir Naturg., xiii, pt. i, 1847, 212. 
Type, Turdus tintinnabulatus Gmelin=Formicarius cantator Boddaert. (Guiana 
and upper Amazon Valley; two species.) 
6 Including Myrmelastes Sclater, which I am unable to separate generically. 
¢ Myrmoderas Ridgway, Proc. Biol. Soc. Wash., xxii, April 17, 1909, 70. Type 
Myiothera loricata Lichtenstein. 
Besides the type, the following species (placed in Myrmeciza by Dr. Sclater) also 
belong here: M. cinnamomea (Gmelin), M. ruficauda (Maximilian), M. squamosa 
(Pelzeln), and MM. atrothorax (Boddaert); probably also Myrmeciza pelzelni Sclater and 
M. hemimelena Sclater, which, however, I have not seen. The group ranges from the 
Guianas and Amazon Valley to southeastern Brazil. 
@T am not at all satisfied with these characters, but am unable to find better ones 
for separating these two exceedingly distinct genera from the rest, collectively. They 
doubtless possess marked anatomical differences, for they certainly stand clearly apart 
from all the rest of the family. 
€ Chamezxza Vigors, Zool. Journ., ii, 1825, 395. Type, C. meruloides Vigors= Turdus 
brevicaudus Gmelin.—Chamezzosa (emendation) Cabanis, in Wiegmann’s Archiv fiir 
Naturg., i, 1847, 218. (Colombia to southeastern Brazil; six species.). 
