338 



REVIEW OP AMERICAN BIRDS. 



[part I, 



In a pretty extensive series of specimens of South American 

 Vireos, whicli have been referred to V. chivi, agilis, hartramii, etc. 

 of authors, supposed to be synonyms of the same species, I find 

 considerable differences which apparently indicate the presence of 

 two or even three species, differing almost too much in size and 

 coloration to be considered the same. I have therefore selected the 

 specimens from Captain Page's Paraguay expedition as typical of 

 the oldest name, V. chivi, based on Azara's descriptions. These 

 specimens, two in number, agree with Azara's bird in the small size ; 

 the coloration is less intense than in the rest, the yellow of the under 

 parts being not much brighter than in olivaceus, but as a spring 

 plumage this is to be expected, if, as is probable, Azara's descrip- 

 tion was taken from autumnal birds. 



The great inferiority in size to V. olivaceus, and the difference in 

 the wing formula, will at once distinguish this species or race. The 

 coloration of No. 16,340 is almost precisely that of No. l,418j the 

 type of the description of V. olivaceus, the olive being only a little 

 deeper, the axillars brighter yellow. 



If there are two species of South American Vireos of the chivi 

 type, as suggested, the more southern appears to be the smaller 

 and the northern one the larger, although not closely restricted. 

 Thus a specimen in the collection labelled " Buenos Ayres," possibly 

 erroneously, however, is as large as the largest, while two from 

 Bahia are as small as the La Plata skins described. 



Locality. 



When 

 Collected. 



Received from 



Collected by 



Bahia, Brazil. 



Brazil. 

 Vermejo River. 



Oct. 18.59. 

 Feb. 1860. 



Dr. G.jCabanis. 

 Cab. Lawrence. 

 Capt. Page, Expl. 

 " [of Parana. 



Chr. Wood. 



VireosylTia agilfs. 



Lanius agilis, Light. Verz. Doubl. 1823, no. 526 (Bahia, Brazil).— 

 ? Thamnophilus agilis, Spix, Av. Bras. II, tab. xxxiv, fig. 1. — Phyllo- 

 manes agilis, BuBM. Th. Bras. Vogel, II, 1856, 108. — Vireosyhia 



agilis, Sclatek, P. Z. S. 1860, 64, 273 (Ecuador) Ib. Catal. 1861, 



44, no. 263 (Bogota, etc.). 



Vireo hartramii, Swainson, F. B. A. II, 1831, 235 (not of Aud.). 



Vireosyhia virescens, Cassin, Pr. A. N. So. 1851, 151.— Sclatee, P. Z. S. 

 1855,151 (Bogota).— FiVco virescens, Baird, Birds N. Am. 1858, 

 333 (Brazil), not of Vieill. 



Hab. South America ; south to Buenos Ayres, Ecvador, Guatemala. 



