48 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 
series, that on outer side sometimes indistinct, especially on upper 
portion; middle toe, with claw, much shorter than tarsus; outer toe, 
without claw, reaching to or slightly beyond middle of subterminal 
phalanx of middle tose, fhe inner toe slightly shorter; hallux about 
as long as inner toe but much stouter; basal phalanx of middle toe 
wholly united to outer toe, for about half its length to inner toe; 
claws moderate in size and curvature, that of the hallux decidedly 
shorter than the digit. Plumage full, soft, and blended, that of the 
rump elongated and lax; feathers of crown and occiput (especially 
the latter) elongated, forming a more or less distinct decumbent crest 
of broad, rounded feathers. 
Coloration.—Adult males with pileum, wings, and tail black, the 
rest of upper parts gray or gray and black, in some species wholly 
black, except for white concealed patch on back and white wing- 
spots; back with a large concealed patch of white, the wings and 
tail with white markings; under parts gray, sometimes whitish on 
abdomen, etc., sometimes entirely black; adult females brown (some- 
times: partly rufescent) above, with whitish markings on wings and 
concealed white patch on back, paler brownish or rufescent below. 
Nidification.—Nest pensile, vireo-like; eggs white or creamy white, 
spotted or streaked with brownish. 
Range.—Honduras to Cayenne and southeastern Brazil. (About 
twelve species. )* 
@ The type of Erionotus (Thamnophilus cxrulescens Vieillot), together with Thamno- 
philus melanochrous Sclater and Salvin and probably several others referable to the 
same group (I have not seen T. tschudit Pelzeln, T. xthiops Sclater, T. cinereo-niger 
Pelzeln, T. stellaris Spix, T. tristis Sclater and Salvin, T. capitalis Sclater, nor T. 
cinereiceps Pelzeln), differs so much in relative size and shape of the bill from 7. 
ambiguus Swainson, T. nevius (Gmelin), T. gorgone Thayer and Bangs, and related 
forms that there is some question as to whether the two groups are really congeneric; 
indeed, I have placed them together mainly on account of their very close resem- 
blance to one another in style of coloration. 
Another group, composed of species (referred by Dr. Sclater to the genera Thamno- 
philus and Dysithamnus) distinguished by their very plain (mainly gray, slate colored 
or sooty) coloration, without black wings or tail and destitute of white markings on 
wings and tail or of a distinct white dorsal (concealed) patch, I do not, at present at 
least, refer to Erionotus. These species (Thamnophilus murinus Pelzeln, T. simplex 
Sclater, JT. capitalis Sclater, T. inornatus Ridgway, Dysithamnus leucostictus Sclater, 
Thamnophilus schistaceus D’Orbigny, Dysithamnus ardesiacus Sclater and Salvin, D. 
unicolor Sclater, D. plumbea (Maximilian), and D. subplumbeus Sclater and Salvin) 
differ considerably among themselves in structural details and may represent two or 
more distinct groups. Since they are all extralimital to the present work, however, 
I leave them as a problem for others to work out. 
