246 Bulletin American Museum of Natural History. [Vol. XXXVI, 



this feature) the increasing brownness of the back and breast and of stripes 

 in the latter would incline me to extend the range of griseocauda southward 

 through the greater part of Nicaragua. 



With the full development of the characters which constitute griseocauda, 

 it is interesting to observe that we have in Mexico a race of magnirostris 

 which more closely resembles R. m. nattereri of southern Brazil than it does 

 any of the geographically intervening races. 



The excellence of my material has induced me to depart for a moment 

 from the consideration of our Colombian specimens, to which, having now 

 determined the features which distinguish ruficauda and magnirostris, we 

 may return. 



As has been stated under that form, magnirostris occupies the greater 

 part of Colombia, even occurring on the Pacific Coast. We have, however, 

 sixteen specimens from the Cauca Valley region which are obviously refer- 

 able to ruficauda rather than to magnirostris. None are without at least 

 a trace of tawny in the tail. In some it is reduced to a minimum, in others 

 it covers most of the interspaces. The color of upper tail-coverts and under 

 wing-coverts is, on the whole intermediate; but the buffy color and bright 

 tawny bars of the abdominal region and thighs is clearly that of ruficauda. 



Five specimens frota Salento are nearest magnirostris. One of these 

 might be considered typical of that form were it not for a trace of tawny 

 on the outer pair of rectrices. 



The capture of a specimen, which I refer to ruficauda, at Noanama re- 

 quires comment since a specimen from the Atrato, north of Noanama, is 

 wholly typical of magnirostris. 



So far as tail markings are concerned this bird, which is in fresh adult 

 plumage, is nearer magnirostris, the outer feathers only showing a trace of 

 tawny, but its deep buffy tawny barred belly, thighs, and under wing-coverts 

 are those of ruficauda while the upper tail-coverts are more like those of 

 ruficauda than of magnirostris. 



The presence of this form at Noanama I take to represent- the south- 

 ward extension of ruficauda along the Pacific coast lowlands, whence its 

 occurrence at Las Lomitas indicates that it has reached the Cauca Valley 

 by crossing the Western Andes. The bird of western Ecuador which I refer 

 to magnirostris, may have reached that region directly from the east, as have 

 many other Amazonian forms. 



Noanamd, 1; Las Lomitas, 1; Call, 3; Guengiie, 2; Popayan, 1; La 

 Manuelita, 2; Miraflores, 1; Rio Frio, 1; Salento, 5. 



