BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 343 



(wing, 96 mm.). The specimen from Mendoza has a wing measure- 

 ment of 96 mm., while another from the same Province, in the 

 United States National Museum collections (taken by Weisshaupt), 

 measures 92.5 mm., figures that cast some doubt upon supposed dif- 

 ference in size in birds from southern localities. 



PYGOCHELIDON CYANOLEUCA (Vieillot) 



Hirundo cijanoleiica Vieillot, Nouv. Diet. Hist. Nat., vol. 14, 1817, p. 509. 

 (Paraguay.) 



Near Lazcano, Uruguay, the present species was recorded from 

 February 5 to 8, 1921, and two, an immature female and an adult 

 male, were taken February 7 and 8. The immature bird, only re- 

 centlj' from the nest, has breast and flanks washed with buffy brown. 

 It is possible that swallows recorded at La Paloma January 23, San 

 Vicente January 26 and 31, and Rio Xegro February 17 and 18 (all 

 in Uruguay) were also this species. 



There is consideral)le doubt in my mind as to which of the two 

 closely allied Pygochelidon is intended by Vieillot's Hirundo cyano- 

 leuca- The description in Azara of the Golondrina de la timoneles 

 n^gros on which Vieillot's name is based may apply with almost 

 €qual propriety to either of the birds at present known as cyanoleuca 

 or patagonica, as the present quotation from Azara ^* will show. 

 ^'Longitud 4-11/12 pulgadas, y las demas medidas a proporcion de 

 la anterior [the barn swallow]. Del pico a la cola, todo el resto 

 «ncima y el costado de la cabeza, son turqui. La cola, remos y 

 cobijas, son lo mismo que en la precedente, aunque sin gotas blancas 

 €n la cola. La tira que en la mencionada se adelanta desde la raiz 

 del ala, en la presente es parda, y termina al fin de la garganta con 

 una manchita obscura. De la horqueta a la cola bianco, con los 

 timoneles inferiores negros, 6 casi como el lomo. La cola y remos 

 debaxo pardos, como las tapadas; aunque las de junto al encuentro 

 tienen ribetillos blancos." Small size {patagonica measures 125 mm, 

 or more in length) is the only absolute character in the above that 

 indicates cyanoleuca, as the colors described may apply to either 

 species. It must be stated that patagonica is the only species that I 

 heve seen from Paraguay since the specimen (in the United States 

 National Museum) cited by Chapman ^^ as from Paraguay in reality 

 comes from the Rio Paraguay, in southern Brazil. The only Pygo- 

 chelidon that I collected in Paraguay (taken 200 kilometers west of 

 Puerto Piuasco) was patagonica. Chapman has called attention 

 to the rarity of records for the species with dark underwing coverts 

 in the interior lowlands of South America, and it is my impression 



« mst. Nat. Pax. Paraguay, vol. 2, 1805, p. 508. 



"'Am. Mus. Nov., No. 30, Feb. 28, 1922, pp. 1, 3, and 11. 



