388 bulletin: museum of comparative zoology. 



50.0-56.0 (52.7); tarsus, 17.5-19.0 (18.3); exposed culmen, 12.0-13.0 

 (12.4). 



Range. — Guiana (French, Dutch, British). Venezuela, Trinidad, 

 Tobago. 



Specimens examined. — French Guiana: Cayenne (including 

 trade skins), 7 d'c? , 4 9 9; Mana, 8 cfcT, 5 99. Dutch Guiana: 

 Vicinity of Paramaribo, 1 cf . British Guiana: Mount Roraima, 1 cf ; 

 "Demerara," 1 d^, 1 9 . Venezuela: Eldorado, Rio Cuyuni, 1 cf ; 

 Rio Yuruan, 1 9 ; San Antonio, Bermudez, 1 cf ; Cumanacoa, 

 Bermudez, 1 d^, 1 9 ; El Pilar, 1 cf ; Las Quigas, 1 cf , 2 9 9; San 

 Estaban, 1 cf , 1 9 ; Aroa, Bolivar R. R., 1 9 ; Lagunita de Aroa, 

 2 cTd", 1 9 ; Sierra de Carabobo, 13 cTd', 6 9 9; El Trompillo, 

 Carabobo, 8 cTcf, 2 9 9 ; Merida, 2d'&; "Venezuela," 1 d", 2 9 9 . 

 Trinidad : Provincetown, 1 cf , 3 9 9 ; Heights of Aripo, \ (^ , \ 9 ; 

 Heights of Orepouche, 1 d", 1 9 ; Sta. Emilia, 1 9 ; "Trinidad," 

 2 d'd'. Tobago: 2 d^d", 1 9. Total, 91. 



Remarks. — This is the most variable of all the forms of P. poly- 

 choptcrus, and a study of its various plumages is extremely interesting, 

 especially in relation to allied forms. 



There is good reason to believe that the species, and more particu- 

 larly this subspecies, is dichromatic, presenting a black-bellied phase 

 and a gray-bellied phase, both with or without mottled rump, under 

 parts, or under tail-coverts. In the dark phase some specimens are 

 very much like P. p. variegahis, the rump being quite black like the 

 back. In the gray phase the bird closely resembles the Santa Marta 

 form, from which it differs in being smaller, slightly darker, and, as a 

 rule, much more mottled. 



Two immature birds from Trinidad (A. M. N. H. 59,252, 59,253) 

 are of interest in this connection, in that they are changing directly 

 from the olivaceous plumage of the young bird into the very black of 

 the adult, although several fully adult birds, from the same place, that 

 have passed wholly through the change, ha^'e gray, not black, under 

 parts. On the other hand an immature bird from Aroa, Bolivar R. R., 

 Venezuela, and another from Sierra de Carabobo, Venezuela (Carnegie 

 mus., 36,344 and 47,768), are apparently changing directly from the 

 olivaceous into the gray, not black, phase, while from the same general 

 region we haxe black as well as gray-bellied adults. 



Birds from Guiana are, as a rule, larger than birds from Venezuela, 

 but the difference is \'ery slight and not by any means constant. 



A few words in regard to the nomenclature and synonymy of this 

 interesting form are necessary here. 



