308 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



of the primaries, as a subspecies of nigra (in which the inner webs of 

 the primaries are black in the adult male, and cinnamon in the fe- 

 male and immature male). The only specimens of oreas that I have 

 seen are from Peru, and show no evidence of intergradation. 



Adult males have the eighth and ninth primaries narrowed dis- 

 tally, with the seventh and tenth of normal width. As the narrowed 

 feathers are concealed beneath the external primary they seem not to 

 have been noted previously. In the male in first winter plumage, and 

 the female at all seasons, all of the flight feathers are normal. 



At all seasons of the year these interesting flycatchers frequent 

 open ground, preferably near water, where they hop or run about 

 on the ground, pausing to peck at the turf or to throw the head up 

 and flit the wings rapidly. They are almost as terrestrial as pipits, a 

 fact that may account for the elongated pipitlike claw on the hallux ; 

 like birds of that group they often seek elevated perches on little 

 mounds of earth. They also fly up to rest on fence posts, or low 

 bushes. Their flight is tilting and usually carries them only a foot 

 or two above the ground. During the breeding season, near Zapala, 

 males were common in the close-cropped grass of the lowland pas- 

 tures, often in the vicinity of barrancas. As 7mfa has been supposed 

 to breed only in Patagonia, it is unfortunate that a fine male that I 

 watched for some time on January 16, 1921, near Carrasco, Uru- 

 guay, was not secured. 



During the winter season rufa comes north to winter in abundance 

 on the open pampas, but does not seem to penetrate beyond the limit 

 of the plains. By March 3 I found the birds common on the level 

 flats bordering the Laguna del Monte near Guamini, Buenos Aires, 

 where they associated in little flocks. Others continued to arrive 

 from the southward, driven up by the encroachment of cold in their 

 summer homes. The birds now had the full lax plumage that pro- 

 tects them in winter, and ran about on the open flats unmindful of 

 the heavy wind, as they made no effort to seek shelter from its blasts. 

 In early morning members of the little scattered flocks pursued one 

 another or chivied passing pipits vivaciously. On March 23, near 

 Tunuyan, Mendoza, a flock of 15 arrived suddenly on the flats bord- 

 ering the river, evidently a migrant flock from the south. 



Like many other pampas birds, during winter they were entirely 

 silent; and as my experience with them in summer was limited, I 

 heard no calls from them whatever. 



FLUVICOLA ALBIVENTER (Spix) 



Muscicapa albiventer Spix, Av. Spec. Nov. Brasiliam, vol. 2, 1825, p. 21, 

 pi. 30, fig. 1. (Brazil.) 



An adult female shot at Formosa, Formosa, on August 23, 1920, 

 was found among open brush and saw grass at the border of a marsh, 



