Cory — The Genus Rhynchocylus. 221 



Range: Northeastern Peru (Ucayali; Exberos; Pebas, Nauta; Upper 

 Ucayali; Yurimaguas); southeastern Peru (Cosnipata) ; eastern Ecuador 

 (Napo); northwestern Brazil (Teffe, upper Amazon). 



Rhynchocyclus poliocephalus sclateri Hellmayr. 



Rhynchocyclus poliocephalus sclateri Hellmayr, Verh. zool.-bot. Gesell. 



Wien, liii, 1906, p. 207 (Barra de Rio Negro, N. Brazil Manaos). 

 Rhynchocyclus poliocephalus (nom. nud.) Pelzeln, Orn. Bras., 1869, p. 110 



(Barra de Rio Negro; Maribitanas and Bahia). 

 Rhynchocyclus megacephalus (nee Tyrannula megacephala Swainson) 

 Sclater, Cat. Bds. Brit. Mus., XIV, 1888, p. 170 (Para, Brazil; De- 

 merara, Merume Mts. and Carimang, British Guiana). 

 Range: Northern Brazil (Rio Negro and Rio Madeira and eastward in 

 Amazon region; Rio Tapajoz; Rio Tocantins; Rio Jamunda, etc., to Para); 

 eastern Brazil (Bahia); 1 eastern Venezuela (Lower Orinoco and Caura 

 River); 2 British Guiana; French Guiana; Dutch Guiana. 



This form is similar to R. p. poliocephalus from Peru, but differs in its 

 larger size and somewhat smaller bill; by its whitish gray, instead of olive 

 yellowish throat; grayish fore-neck (only slightly washed with olive yellow- 

 ish), and paler yellowish under parts. Wing (type ex. by Hellmayr) 573^; 

 tail 53 mm . The average wing measurements of 4 males amd 5 females from 

 Oyapoc and Nana River, Cayenne, in the Carnegie Museum, males — wing 

 55; females — wing 54 mm. 



Rhynchocyclus poliocephalus klagesi (Ridgway). 



Rhynchocyclus klagesi Ridgway, Proc. Biol. Soc. Wash., XIX, 1906, p. 

 115 (Maripa, Venezuela). 



Range: Upper Orinoco River, Venezuela (Maripa and foot of Mt. Duida) ; 

 S. E. Colombia (La Morelia and Florencia). 3 



This form is obviously closely related to R. p. sclateri, but differs in its 

 brighter yellowish belly and in its yellowish-olive tinged breast and throat. 

 Size about that of R. p. sclateri. The single specimen from the foot of Mt. 

 Duida, S. Venezuela, has the crown much darker (dusky slate color) than 

 any specimen I have seen of either sclateri or klagesi, but otherwise agrees 

 with klagesi. 



Rhynchocyclus grisescens Chubb. 



Rhynchocyclus grisescens Chubb, Ibis, 1910, p. 588 (Sapucay, Paraguay). 

 Range: Southeastern Paraguay (Sapucay). 



1 Hellmayr (Novit. Zool., XVII, 1910, p. 298, footnote) has examined the specimen in 

 the British Museum recorded by Sclater, Cat. Bds. Brit. Mus. XIV, 1888, p. 170, as speci- 

 mens "a" "Brazil" under megacephalus, and learned that it came from Bahia and that it 

 proves to be this form. 



2According to Hellmayr (Novit. Zool., XVII, 1910, p. 298, footnote) specimens recorded 

 by Berlepsch & Hartert from La Pricion, Caura River, Venezuela, as this form, prove to be 

 a form of sulphurescrns. If so, they are probably aasimilis, which also occurs in that region. 



3Specimens in American Museum of Natural History. 



