the Province of Buenos Ayres. 201 



every season except the spring. I shot one on the 17th Oc- 

 tober last near Punta Lara, which was flying steadily in a 

 north-westerly direction in company with another. Total 

 length 13"5, beak 1*4, tarsus -5. Iris wood-brown; base and 

 tip of beak dull yellow, remainder black ; legs and feet dark 

 red, between scarlet and carmine ; head white, with a long- 

 black streak in front of and behind the eye ; remainder of 

 the plumage pearl-grey. On the 5th August I observed two 

 Black-headed Terns fishing in some lagoons to the north of 

 Buenos Ayres. They appeared to me to be Sterna cassini ; but 

 I am not aware that that bird comes so far north as this*. 



137. Sterna superciliaris, Vieill. ; Scl. et Salv. P. Z. S. 

 1871, p. 571. 



Frequents shallow inland lagoons and small streams, and 

 is also found in the river. Its habits resemble those of Sterna 

 minuta at home. I observed specimens in May 1875 at 

 Montevideo, and in April of the present year at Baradero. 

 Iris wood-brown ; beak and legs pale orange. 



138. Larus dominicanus, Licht. ; Scl. et Salv. I. s. c. 

 p. 576. 



Pretty common and generally distributed ; but I have not 

 seen it in the neighbourhood in the spring or summer. In 

 the winter it wanders far inland. 



139. Larus cirrhocephalus, Vieill. ; Scl. et Salv. /. s, c. 

 p. 578. 



I have not observed this bird to the south of Buenos Ayres, 

 but have constantly seen it from March to July to the north 

 of the city. Unlike Larus maculipennis , it never wanders 

 inland, but frequents the shallow shores of the La Plata, 

 feeding on dead fish or ofl:al, and flocking round the fishermen 

 when they are hauling their nets to get a share of the spoil. 

 As a rule, this species does not mix with Larus maculipennis, 

 though now and then they are seen together ; but all the flocks 

 or parties I have observed when flying from one spot to 



* [In our paper on Neotropical Laridse we have shown that this species 

 is found as far north as Santa Catherina, Brazil (P. Z. S. 1871, p. 570). — 

 Edd.] 



