under wino--coverts pale smoky brown, the external coverts slightly mottled with blackish bases ; 

 quills dusky below : " bill, legs, and iris black" [A. Peel). Total length 5-5 inches, culmen 0-35, 

 wing 4-45, tail 1-9, tarsus 0"5. 



The specimen described is in the British Museum. It was obtained by Mr. Alan Peel in 

 Uruo-uay in August 1877, and appears to be a tolerably adult bird, though the remains of smoky 

 brown tips to the white feathers of the rump may be a sign of immaturity, as specimens collected 

 by INIr. Hudson at Conchitas, in September, have the rump pure white. 



Tliere appears to be no difference in the colouring of the sexes, and the measurements are as 

 follows : — 



Total length. Culmen. Wing. Tail. Tarsus, 



in. in. in. in. in. 



S imm. Rio Grande do Sul {Joijner) .... 5-0 OSo 4-4 1-8 0-45 



¥ imm. „ „ „ .... 5-5 0-4 4-45 1-9 0-45 



? imm. Uruguay [A. Peel) 5-5 0-35 4-45 1-9 0-5 



ad. Brazil [Mus. P. L. S.) 5-0 0-4 4-5 1-9 0-5 



ad. „ [Albuquerque) 5-2 0-35 4-5 1-85 0-5 



? ad. Conchitas, Buenos Aires (W. H. Hudson) 5-3 0-35 4-5 1-85 0-5 



? ad. „ „ „ 5-4 0-35 4-6 1-9 0-45 



? ad. Cosnipata, Peru [H. Whitely) . . . . S'O 0-35 4-7 1-85 O'S 



Young birds apparently have smoky brown tips to the feathers of the rump, and also distinct white 

 margins to the secondaries and upper tail-coverts. 



Hab. Southern Brazil, Uruguay, Patagonia, and Peru. 



The celebrated Portuguese naturalist Azara seems to have been the first to describe the 

 present species, in his work on the natural history of Paraguay, and on his description 

 Vieillot founded his Ririmdo leucorrhoa. The next mention of the species appears to 

 have been by Mr. Gould, who redescribed it from specimens obtained by Mr. Darwin at 

 Monte Video during the voyage of the ' Beagle.' He called it Hirunclo frontalis, and 

 gave a somewhat careless description, omitting all mention of the characteristic white 

 rump. As the name of frontalis had already been bestowed on an Australian sj)ecies of 

 Swallow by Messrs. Quoy and Gaimard, the late Mr. Cassin proposed in 1850 to call the 

 Brazilian species H. goiildi ; but in 1853 he recognized that it was the same as Sinmclo 

 leucorrhoa of Vieillot, and suppressed his name of S. gouldi. 



Azara describes the present species as common in Paraguay, nesting in the 

 holes of trees, but on the La Plata river, where there are no trees, in holes in the 

 ground. 



Most of the specimens examined by us have been from the neighbourhood of Buenos 

 Aires, and some excellent accounts of the habits of the species are given below. 

 Mr. Darwin's specimen which he obtained at Monte Video is not in the British 

 Museum. In the collection of Messrs. Salvin and Godman are a pair of birds from 

 Pelotas, in Bio Grande do Sul, collected by Mr. Joyner, and Natterer obtained examples 



