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 toe, the 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 wmgs 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. 



Nidijication. — 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 Erionoius (Thamnophilus cscrulescens Vieillot), together with Thamno- 

 pMlus melanochrous Sclater and Salvia and probably several others referable to the 

 same group (I have not seen T. tschudii Pelzeln, T. sethiops 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 T. 

 ambiguus Swainson, T. nxvius (Gmelin), T. gorgonx 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, T. 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. 



