632 



PATAGONIAN EXPEDITIONS : ZOOLOGY. 



Nomencl. Av. Neotr. p. 119 (1873: Falkland Is. and Patagonia); 

 Sharpe, Cat. B. Brit. Mus. I. p. 171 (1874: Port Famine, South Pat- 

 agonia: Falkland Is.), Gurney, Ibis, 1876, p. 69; id. List Diurn. B. 



Fig. 320. 



Butco poliosoiiia. Adult male. Natural size. 



Prey, p. 70 (1884); Burm. Ann. Mus. Nac. Buenos Aires, III. partx, p. 

 241 (1888: Patagonia: Straits of Magellan; Falkland Is.); Oust. 

 Miss. Scient. Cap Horn, Oiseaux, pp. 22, 324 (1891: Orange Bay, 

 June: Beagle Canal, Aug.); Sharpe, Hand-List B. I. p. 255 (1899); 

 Martens, Hamb. Magalh. Sammelr. p.-5 (1900: Tierra del Fuego: 

 Falkland Is.). 



General description. 



Size. — Adult male. 



Total length, about 22.50 inches. 



Wing, 15.5 inches. 



Culmen, 1.5 inches. 



Tail, 8.0 inches. 



Tarsus, 3.5 inches. 



Color. — Adult male. — General color: Lead-color throughout, except on 

 the tail-coverts and the tail, which are white with dark markings. 



Head : Bluish lead-color, lighter than on the back ; lores and ear-coverts 

 still lighter, approaching white. 



