FAMILY THRAUPIDAE 



475 



scarlet, and extending to nape; lower back bright yellow; central lesser 

 wing coverts bright yellow; rest of upper surface, including tail and 

 rest of wings, black; becoming slightly more grayish in center of belly; 

 sides at base of wing and underwing coverts white. 



Adult female of nominate race and both sexes of H. x. rubrifrons, 

 upper surface very dark gray, except for bright yellow lower back, 

 rump, and upper tail coverts; wing coverts dark gray; remiges and 

 rectrices black; undersurface lighter gray, tinged yellow on undertail 

 coverts: sides at base of wing and underwing coverts white. 



Immature male of nominate race, like adult with gray undersurface 

 gradually replaced by black; black feathers of upper back tipped 

 greenish. 



This species is represented in Panama by two races, the nominate 

 form, of eastern Darien and Colombia, and rubrifrons of the entire 

 Caribbean slope, and eastern Costa Rica. A third race, bcrliozi, is 

 found in western Colombia and northwestern Ecuador. The name ru- 

 brifrons, seemingly more applicable to the other forms of the genus, 

 the males of which have prominent patches of red on the head, was ap- 

 plied to a specimen that had evidently been stained by some sort of 

 fruit that made the feathers appear reddish (Lawrence, Proc. Acad. 

 Nat. Sci. Phila., 1867, p. 94). Many authors have maintained rubri- 

 frons as a separate species from H. xantho pygius but both Hellmayr 

 (Cat. Birds Am., pt. 9, 1936, p. 345) and Storer (Check-list Birds 

 World, vol. 13, 1970, p. 288) considered it to be no more than a hen- 

 plumaged subspecies of xantho pygius. Specimens of rubrifrons are 

 somewhat smaller, with less robust bills than the other forms of Hetero- 

 spingus, but the differences between females would ordinarily probably 

 not be accorded more than subspecinc significance. Males of rubri- 

 frons, however, differ greatly from those of the other forms of the 

 genus in lacking the black plumage, red supra-auricular stripes, and the 

 yellow patch on the lesser upper wing coverts. There is no evidence of 

 intergradation between rubrifrons and xanthopygius, but the ranges 

 of the two are not certainly known to coincide, so this is inconclusive. * 



The Sulphur-rumped Tanager inhabits humid forests and forest bor- 



*Haffer (Bonner Zool. Monogr. no. 7, 1975, p. 167) cites "Wetmore (1965 and 

 pers. comm.)" as collecting both rubrifrons and xanthopygius on the Rio Jaque, 

 but Wetmore (Oiseau, vol. 35, 1965, p. 159) actually only mentions the nominate 

 form as occurring there, and there is but a single specimen of Heterospingus in 

 the Smithsonian collections from the Rio Jaque, this being a female of H. x. 

 xanthopygius. Haffer also appears to have erred in including Cerro Sapo and 

 Pucro in the range of H. x. rubrifrons, and his distribution maps of the forms of 

 Heterospingus are thus somewhat misleading. S.L.O. 



