BANGS AND PENARD: NOTES ON AMERICAN BIRDS. 383 



upper parts Aarics from brownish olive to grayish green, with all 

 intermediate shades, but that of the under parts is more constant and 

 practically the same in all the forms. In general, females of the paler 

 forms are more yellowish below than those of the darker forms, and 

 young females of all forms have much brighter yellow under parts than 

 do adults. 



The species is distributed over the entire forested area of Central 

 and South America from Honduras to northern Argentina, and is 

 represented by eight forms of which two, P. p. tristis and P. p. costarl- 

 censis, are respectively so close to P. p. variegatus and P. p. similis, 

 that further investigation with larger series for comparison may prove 

 them to be identical with the latter. 



The largest form is found in the southernmost portion of the range 

 of the species, while the smallest members inhabit Costa Rica, Ni- 

 caragua, and Honduras. 



The darkest form is P. p. variegatus of the Upper Amazon. South- 

 ward and northward from there the species becomes more variable 

 tending toward paler forms, attaining the palest coloration in P. p. 

 cnstariccnsis of Costa Rica. 



The form inhabiting Guiana, Venezuela, Trinidad, and Tobago, 

 presents the greatest individual Aariation, from very dark birds, almost 

 the equal of P. p. variegatus, to pale birds closely resembling those 

 inhabiting the Santa Marta region in Colombia. But we cannot find 

 any constant characters distinguishing birds from any portion of the 

 range of this form. On the contrary, specimens with mottled under 

 parts, with or without mottled rumps and under tail-coverts, are 

 found over the entire range. Nor can we detect any constant dif- 

 ference in the degree of freckling or paleness of the under parts. 



In all the forms the paler specimens show more or less pronounced 

 traces of whitish lores. These are particularly noticeable in young 

 birds, but are never so distinct as in P. marginatus, nor do they ever 

 meet at the base of the forehead to form a distinct band as in that 

 species. 



The forms are: — 



1. PACHYRH.'yVIPHUS POLYCHOPTERUS POLYCHOPTERUS (Vicillot). 



Plotyrhynchos polychopterus Vieillot, Nouv. diet., 1818, 27, p. 10 ("Nouvelle- 

 Hollande," error — South Brazil substituted by Hellmayr, Abh. K. Bayer, 

 akad. wiss., 1906, 22, Abt. 3, p. 666). Type.— Paris Museum— yirfe 

 Vieillot, {loc. cit.). 



