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(a) R. poliocephalus poliocephalus Tacz. 
Rhynchocyclus poliocephalus Taczmowski, Orn. Pérou ii. p, 285 (1884.—Nauta, N.E. Peru ; type in 
Mus. H. v. Berlepsch) ; Sclater, Cat. Birds Brit. Mus. xiv, p. 171 (part.). 
R. megacephalus (nec Swainson) Sclater & Salvin, Proc. Zool. Soc. Lond, 1866. p. 189 (Upper 
Ucayali: vidi); iidem, /.c. 1867. p, 751 (Xeberos: vidi) ; iidem, /.c. 1867. p. 978 (Pebas) ; 
iidem, /.c. 1873. p. 289 (E, Peru) ; iidem, /.c. 1873. p. 185 (Cosnipata, S,E, Peru) ; Taczanowski, 
1.c, 1882. p. 20 (Yurimaguas) ; idem, Orn. Pérow ii. 1884. p. 283 (part.: Peru). 
R. poliocephalus poliocephalus Hellmayr, Nov. Zool. xiv. 1907. p. 48 (Teffé). 
Hab. N.W. Brazil: Teffé, Rio Solimoéns (Hoffmanns). North-Eastern Peru: 
Upper Ucayali, Xeberos (Bartlett), Yurimaguas (Stolzmann), Pebas, Nauta (Hanx- 
well). S.E. Peru: Cosnipata (Whitely). astern Ecuador: Napo (spec. in 
Mas. H. v. B.). 
Characters. The slate-grey cap decidedly mixed with olive-green, back brighter 
green. Lower parts rather bright yellow, throat scarcely paler than the rest.— 
Wing (3) 56—58, (?) 52—55 ; tail (S) 47, (2) 42—45 mm. 
Examined; 1 adult, Nauta (type); 1 ¢ ad., Hast Ecuador, in Mus. H. v. B.; 
1 3 ad., Upper Ucayali, July 7, 1865; 1 ¢ ad., Xeberos, June 6, 1866 (E. Bartlett 
coll.); 1 ¢ ad., Teffé (Hoffmanns), all three in the Tring Museum, 
(6) R. poliocephalus sclateri Hellm. 
R. poliocephalus sclateri Hellmayr, Verhundl. Zool. Bot. Ges, Wien liii. p. 207 (1903.—Barra do Rio 
Negro ; crit.); idem, Nov. Zool. xiii. 1906. p. 361 (Prata, Pard) ; Snethlage, Journ, f. Ornith. 
1908. p. 527 (Arumatheua, Tocantins) ; Berlepsch, Nov. Zool, xv. 1908. p. 131 (Cayenne). 
R. sulphurescens (errore !) Sclater & Salvin, Proc. Zool. Soc. Lond. 1867, p. 578 (Para: vidi). 
R. poliocephalus (nom. nud.) Pelzeln, Zur Orn. Bras. ii. 1868. p. 110 (Barra do Rio Negro, Mara- 
bitanas, Rio Negro ; Bahia—vidi) ; Sclater, Cat. Birds Brit. Mus. xiv. p. 171 (part.: specimen 
ex Pard—Layard : vidi) ; Berlepsch & Hartert, Nov. Zool. ix, 1902. p. 47 (part.* : Nericagua, 
Maipures, Suapure). 
R. megacephalus (errore) Layard, Ibis 1873. p. 383 (Pard: vidi) ; Taczanowski, Orn, Pérou ii. 1884. 
p. 283 (part.: Cayenne); Salvin, Jbis 1886. p. 501 (Rio Carimang, Brit. Guiana); Sclater, 
Cat. Birds Brit, Mus. xiv. p. 170. 
R. klagesi Ridgway, Proc. Biol. Soc. Wash. xix. p. 115 (1906.—Maripa, Caura, Venezuela). 
Hah. North Brazil: Arumatheua, on the R. Tocantins (Snethlage) ; Para 
(Layard, Wallace), S. Antonio do Prata, near Para (Hoffmanns); Marabitanas and 
Barra (= Manios), on the Rio Negro (Natterer); Calama, Rio Madeira (Hoffmanns). 
Kast Brazil: Bahia (Kammerlacher coll., Mus. Vindob.; Mus. Brit.+). Cayenne 
(Cherrie, Jelski). Surinam : near Paramaribo (Chunkoo coll. in Mus. Tring). British 
Guiana: Merumé, R. Carimang, Ourumee (Whitely). Venezuela: Nericagua and 
Maipures, R. Orinoco (Cherrie); Suapure, Maripa, Caura R. (Klages). 
Characters. Cap nearly uniform slate-grey or very slightly suffused with 
olive-green ; back duller green than in R. p. poliocephalus. Lower parts pale 
yellow, underlaid with pale greyish on the chest; throat and foreneck greyish 
white or, at least, strongly suffused with whitish. 
Wing (d) 55—60, (2) 52—57 ; tail (3) 45—52, (2) 42—45 mm. 
Obs, Lam unable to discover any constant differences, connected with distri- 
bution, among a large number of skins from various localities, R. klagesi is clearly 
a synonym of sclater’, examples from the Caura being in every respect identical 
with the types. Moreover, Mr. Ridgway compares his alleged new form only with 
R. sulphurescens, from which it is, of course, quite distinct. 
* The examples from La Pricion, Caura, turn out to belong to R. s, sulphurescens. 
+ R. megacephalus Sclater, Cat. Birds Brit. Mus, xiv. p. 170: specimen a. 
