BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 371 



molt. Several seen had lost all of the rectrices and all were in 

 ragged condition. No definite differences are apparent in birds 

 from the localities mentioned.*'- 



This yellowthroat frequented cat-tails or other aquatic growth 

 standing in water, or dense tangles of herbaceous vegetation border- 

 ing wet swales, or other low localities. In this safe cover they crept 

 about cautiously, at times flying for short distances with quick, tilt- 

 ing flight to some safe retreat among the grasses. Though often 

 common it was difficult to catch sight of them. Their call note was 

 a harsh tseep tseej)-, quite different from the scolding call of Geo- 

 thlypis triehas. I did not identify their song. 



COMPSOTHLYPIS PITIAYUMI PITIAYUMI (Vieillot) 



Sylvi-a pitiayiimi Vieillot, Nouv. Diet. Hist. Nat., vol. 11, 1817, p. 276. 

 (Paraguay.) 



The present species, with a broad distribution through humid 

 wooded areas in the northern half of Argentina, was recorded at the 

 following points : Kesistencia, Chaco, July 8 to 10, 1920 (male, July 

 8); Las Palmas, Chaco, July 13 to 30; Eiacho Pilaga, Formosa, 

 August 18; Formosa, Formosa, August 23 and 24; Kilometer 25, west 

 of Puerto Pinasco, Paraguay, September 1 (male) ; Kilometer 80, 

 west of Puerto Pinasco, September 6 to 21 (male, September 8) ; 

 Cerro Lorito, opposite Puerto Pinasco, September 30; San Vicente, 

 Uruguay, January 28 to 31, 1921 (adult male, January 28) ; Lazcano, 

 Uruguay, February 5 to 8 (immature male and female, February 5) ; 

 Kio Negro, Rio Negro, February 15 (one with sex not determined) ; 

 Tapia, Tucuman, April 6 to 13 (immature female, April 9; Tafi 

 Viejo, Tucuman, April 17 (male). 



The series of specimens taken is fairly uniform with exception of 

 a male in fresh plumage shot April 17 at an altitude of 1,800 meters 

 on the slopes of the Sierra San Xavier. This bird is faintly darker 

 above than typical birds from Paraguay and indicates an approach 

 to the coloration found in C. p. elegans Todd,*^^ though lighter than 

 the average of that form as shoAvn in a series examined from Co- 

 lombia to southern Peru. More recently Todd has described an ad- 

 ditional form, G ompsothlypis p. melanogenys^^ from Yungas de 

 Cochabamba, Bolivia (elevation 1,500 meters), which is said to be 

 much deeper in color, particularly above, than elegans. This I have 

 not seen. It is possible that the bird from the Sierra San Xavier 

 represents an approach toward vielanogenys. Further collections 



"''For the use of the name velata see Hellmayr, Nov. Zool., vol. 28, September, 1921, 

 pp. 243-244. 



*3 Compsothlypis pitiayumi elegans Todd, Ann. Carnegie Mus., vol. 8, May 20, 1912, 

 p. 204. (Anzoategui, Estado Lara, Venezuela.) 



" Proc. Biol. Soc. Washington, vol. 37, July 8, 1924, p. 123. 



