BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 369 



The female shot July 13 had the maxilla and tip of mandible 

 bone brown; base of mandible paler; tarsus tawny olive; feet 

 slightly yellowish; iris very dark brown. 



The single bird from Uruguay is much darker on the flanks and 

 dorsum than those from the Argentine Chaco, differences that may 

 be due to immaturity or freshness of plumage, or may prove to be 

 of subspecific value. The species has not been recorded previously 

 from Uruguay. 



BASILEUTERUS LEUCOBLEPHARmES LEUCOBLEPHARmES (Vieillot) 



Sylvia leucotlepharldes Vieilxot, Nouv. Diet. Hist. Nat., vol. 11, 1817, 

 p. 206. (Paraguay.) 



The present warbler was encountered in the following localities: 

 Eesistencia, Chaco, July 9 and 10, 1920 (one of unlmown sex taken 

 July 9) ; Las Palmas, Chaco, July 13 to 30 (adult female, July 13) ; 

 Kiacho Pilaga, Formosa, August 7 and 18; San Vicente, Uruguay, 

 January 30 (adult female taken) ; Lazcano, Uruguay, February 5 

 to 8 (adult female, February 5) ; Rio Negro, Uruguay, February 

 14 to 18. Specimens secured in Uruguay, in full post-braeding 

 molt, appear darker than skins taken in winter in the Chaco, a con- 

 dition due perhaps to their new plumage. All are assigned to the 

 typical form, though the single skin in United States National 

 Museum that is supposed to represent B. I. superciliosus (Swain- 

 son) ^^ is not in satisfactory condition for comparison. 



Though in the Tableau Encyclopedique et Methodique,^^ Vieillot 

 calls this species S. Leucohlephara^ in the original description the 

 specific name is spelled leucohlepharides. 



Basileuterus I. calus Oberholser "'^ is a synonym of B. I. leucoble- 

 pharides^ since the typical form comes from Paraguay.''^ 



This bird inhabited dense thickets or the heavy growtli tliat 

 often borders clearings, where it frequented low growth or, with 

 constantly wagging tail, walked about on the ground. The birds 

 were inquisitive and came very near to me when suitable cover of- 

 fered, a proximity that intensified the ear-piercing tsee that served 

 them for call note. They were found in pairs. The song of the male 

 was made up of a repetition of a single, clear, whistled note repeated 

 several times in a slowly descending scale that in sound and cadence 

 suggested the song of a canyon Avren {Catherpes mexicanus) but 

 lacked the carrying power of the notes of that bird. A juvenile 

 individual Mas recorded February 5. 



^ Trichas superciliosus Swainson, Anim. in Menag., 1838, p. 295. (Brazil.) 

 =8 Vol. 2, 1823, p. 459. 



"^ Basileuterus leucoblepharus calus Oberholser, Proc. Biol. Soc. Washington, vol. 14 

 Dec. 12, 1901, p. 188. (Sapueay, Paraguay.) 

 •1 See Tabl. Encyc. Meth., vol. 2, 1823, p. 460. 



