AVES TYRANNID^. 8oi 



tarsus, .88. Above olive grayish ; wings dull brown with obscure pale 

 edgings ; tail blackish with white tips to the two outer pairs of feathers, 

 under parts very pale lemon yellow, washed with olive on the sides, super- 

 ciliaries white, lores white with a black spot in front of the eye and a white 

 spot on the lower lid, bill and feet plumbeous black. 



Geographical Range. — Argentina and northern Patagonia (Rio Negro). 



Genus SERPOPHAGA Gould. 



Type. 

 Serpophaga Gould, Zool. Voy. Beagle, iii. p. 49 (184 1) . S. snbcristata. 

 Geographical Range. — Central and South America, from Costa Rica 

 south to southern Patagonia. 



Serpophaga nigricans (Vieillot). 



Silvia nigricans Vieillot, Nov. Diet. d'Hist. Nat. xi. p. 204 (1817), based 

 on "Tachuri obscurito" of Azara (Paraguay). 



Description. — Adult male, 284991, Biol. Survey Colin., U. S. Dept. of 

 Agriculture, Lazcano, Rocha, Uruguay, February 7, 1921. Total length, 

 4.50 inches; wing, 2.30; culmen, .40; tail, 2.14; tarsus, .75. Above 

 gray with a wash of olive, wings and tail blackish brown, with light edg- 

 ings to the tertials and coverts which wear off almost completely ; lower 

 parts light slaty gray, whiter on the throat and washed with olive buff on 

 the sides and flanks, bill and feet black. 



In unworn plumage (June 29), the edging to the tertials is buffy white, 

 and the buff wash on flanks and under tail coverts is prominent. Birds 

 in Juvenal plumage have edgings to wing feathers brown and the buff 

 wash below much darker. 



Geographical Range. — Southern Brazil and Paraguay to northern Pata- 

 gonia. 



Serpophaga parvirostris (Gould). 



Tyrannula parvirostris GoxiXd, Voy. Beagle, Birds, p. 48 (184 1) (Santa 

 Cruz, Patagonia). 

 Description. — Adult male, 7654 P. U. O. C, Punta Arenas, Chile, Janu- 

 ary 3, 1898, A. E. Colburn. Total length, 4.90 inches; wing, 2.70; cul- 

 men, .30; tail, 2.26; tarsus, .70. Above buffy brown (Ridgway), darker 

 and more cinereous on the head, becoming clear gray on the sides of the 

 face and neck, ear coverts dusky ; edgings to wing feathers tawny, most 



