398 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



Genus CCEREBA Vieillot. 



Owefta ViEiLLOT, Ois. Am. Sept., i, 1807, 70. {Ty^e, Gerthia jlaveola Linnseus.) 

 Certhiola Sundevall, CEfv. Vet.-Ak. Handl. Stockholm, 1835, 99. (Type, Cerlhia 



flaveola Linnaeus.) 

 Arbelorhina^ Cabanis, Wiegmann's Archiv. fiir Naturg., 1847, 325. (Substitute 



for Cosreba Vieillot).'' 



Kather small Coerebidse with very acute decui'ved bill, long tarsus 

 (nearly one-third as long as wing) and rounded tail, with very broad 

 rectrices; plumage varied with dusky or grayish and yellow, white, or 

 grayish, or else entirely black. 



Bill about as long as head or a little shorter, strongly decurved ter- 

 minally, with tip very acute; culmen distinctly ridged, gradually curved 

 downward from the base; commissure distinctly arched, most strongly 

 so toward base, the rictal portion fleshy or tumid ; gonys slightly con- 

 cave, its base forming a slight but decided angle; depth of bill at ba,se 

 equal to about one-third exposed culmen or slightly less, the basal 

 width decidedly less than the depth. Nostril exposed, longitudinal, 

 occupying about the lower half of nasal fossa. Rictal bristles obsolete. 

 Wing rather long, rather pointed (eighth, seventh and sixth primaries 

 longest, ninth intermediate between fifth and fourth); wing-tip slightly 

 shorter than commissure, much shorter than tarsus. Tail much shorter 

 than wing (decidedly shorter than distance from bend of wing to tip of 

 secondaries), rounded, the rectrices very broad. Tarsus long (nearly 

 one-third as long as wing), its scutella rather distinct; middle toe, with 

 claw, much shorter than tarsus; basal phalanx of middle toe almost 

 entirely free from inner toe, but united for more than half its length 

 to outer toe. 



Coloration {sexes alike). — ^^Above grayish, olive, or blackish, usually 

 with a yellow patch on rump and a white spot at base of primaries; a 

 white, gray, or yellowish superciliary stripe; under parts whitish or 

 grayish, the breast (sometimes abdomen also) yellow; lateral rectrices 

 tipped with white. (Two species, or possibly representing a color 

 phase of normally colored species, entirely black.) 



Range. — Neotropical Region in general, but wanting in Cuba, the 

 Galapagos Archipelago, and on Pacific coast of South America from 

 Peru southward. 



KEY TO THE SPECIES OF CCEREBA. 



a. Plumage parti-colored (blackish or grayish, yellow, white, etc.). 

 h. A conspicuous and sharply defined superciliary stripe o£ white or yellow, 

 c. Superciliary stripe white. (Adults.) 

 d. Throat unicolored (white, gray, or dark slaty); malar region and whole 

 throat same color, abruptly different from blackish of pileum. 

 c. Throat grayish white or very pale gray (not darker than gray no. 9'). 



' "' ApfiriXoi, Kneif; piv, Nase." 



^See Oberholser, Auk, xvi, Jan., 1899, 32. 



'Ridgway's Nomenclature of Colors, pi. ii, fig. 9. 



