16 



BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



shield, 36.5-44 (39.7); tarsus, 47.5-58 (52.7); middle toe, 48.5-61 

 (54).° 



Adult female— Wing, 124-134 (129.7); tail, 41.5-47 (44.2); bill 

 from nostrU, 16-20 (18.6) ; from posterior margin of frontal shield, 

 41-45 (43.3); tarsus, 52-60 (56.5); middle toe, 54-63 (56.7).^ 



From careful examination of the fairly satisfactory series available, 

 it seems extremely probable that the black-backed specimens (J. 

 nigra) and those with purplish brown or maroon back (commonly 

 called J. melanopygia) are simply color phases of one species. Not 

 only do they occur together wherever either is found, but the two 

 extremes are connected by intermediate specimens, Parra hypo- 

 melxna Gray represents an intermediate condition of plumage, the 

 colored plate indicating a bird with black back and scapulars, but 

 brown wing-coverts and tertials. 



It is possible that these separate phases may be amenable to local 

 influences, to a greater or less degree, the black-backed one pre- 

 dominating in one locality, the maroon-backed one in another. It 

 is significant that the series examined from the Rio Cauca district 

 of western Colombia (five adult males and three adult females) all 

 represent the brown-backed phase. 



Panama (David, Chiriqui; Calobre, Castillo, and Santa Fe, Verd- 

 gua; Lion HiU; Rio Trinidad; Bohio; Laguna de Pital), and Co- 

 lombia (Rio Atrato; Cartagena; delta del Rio Magdalena; Barran- 

 quUla; Santa Marta, Cienega, Fundacion, Mamatoco, and Bonda, 

 Santa Marta; Santa Elena, Antioquia; Bogota; Laguna de Paturia; 

 Guabinas, Rio Cauca) . Northeastern Peru (Sarayacu) ? 



