314 BULKETIN 133, UNITED STATES NATIONAX, MUSEUM 



it had not moved. The directness with which they rose and de- 

 scended gave the same impression as a ball that is snapped into 

 the air to fall back to the hand that had tossed it. This odd action 

 was witnessed frequently and was probably a mating display in- 

 tended for the season of spring. The only call heard from these 

 little birds was a low tsu wip. 



PHAEOTRICCUS HUDSONI (Sclater) 



Cnipolegus hudsoni Sclater, Proc. Zool. Soc. London, 1872, p. 541, pi. 31. 

 (Rio Negro, eastern Rio Negro, Argentina.) 



When Mr. Ridgway''^ characterized the genus Phaeotriccus as 

 new he evidently did so, as shoAvn in his diagnosis, from Entotriccus 

 striaticeps, but for some reason designated Cnipolegus hudsoni 

 Sclater as type. Though the structural characters cited can cover 

 striaticej)s alone, the term Phaeotriccus may be applied only to 

 hudsoni. As it happens Cnipolegus hudsoni Sclater is sufficiently 

 distinct from the typical forms of Knipolegus Boie to warrant its 

 separation so that Phaeotriccus comes into use for a valid generic 

 group. It may be characterized as follows: Similar to Knipolegus 

 Boie, but the three outermost primaries (eight to ten) narrow, 

 tapering gradually from beyond center to tips; seventh primary 

 broader but still narrower than normal ; sixth and seventh primaries 

 about equal; first longer than fourth, shorter than fifth. The 

 wing is illustrated in the original description of the species.^* The 

 male, in addition to a narrow band of white across the primaries, 

 has a white spot on the flanks that is concealed beneath the wing. 



The female of this species does not seem to have been described. 



Males of Hudson's flycatcher were seen near Victorica, Pampa, 

 on several occasions from December 23 to 29, 1920. An adult male 

 was shot December 27, and another December 29, but I have no 

 record of the female. The species is an alert, aggressive little bird 

 that frequents openings in dense scrub, where it selects a low 

 perch from which to watch for food. At times it gives a sharp 

 explosive note followed by a loud popping of its bill. 



The species, according to published notes, has been previously 

 known from eastern Rio Negro (the type-locality) and eastern 

 Mendoza (according to Fontana). 



MECOCERCULUS LEUCOPHRYS LEUCOPHRYS (d'Orbigny and Lafresnaye) 



Muscicapa leucophrys (I'Oebigny and Lafresnaye, Mag. Zool., 1837, cl. 2, 

 p. 53. (Yanacache, Yungas, Bolivia.'*^) 



Three specimens, a male and two females, all immature indi- 

 viduals in molt from juvenal to first winter plumage, were shot 



03 Proc. Biol. Soc. Washington, vol. 18, Sept. 2, 1905, p. 209. 



^ Proc. Zool. Soc. London, 1872, p. 542. 



»° See dOrbigny, Voy. Amer. Mend., vol. 4, pt. 3, Oiseaux, 1835-1844, p. 327. 



