Purayuuy , Bulivin, and Sont/iern Brazil. 471 



It was found breeding on the Rio Paraguay, as I have 

 described under Phaelhusa magnirostris. The nest was a 

 mere hollow scraped in the sand, but deeper and larger than 

 that of its neiglibour. The full clutch is apparently four, 

 though several nests were taken with three e'^g^. 



Twenty-five eggs brought home were taken on the 9th of 

 September at Colonia Risso. 



264. Phaj^thusa magnirostris. 



Pha'etliusa magnirostris Arg. Orn. ii. p. 191 ; Saunders, 

 Cat. B. XXV. p. 23. 



a. ? imm. Tayru, Paraguay. Aug. 5, 1909. 



b. ? ad. Colonia Risso, Paraguay. Sept. 8, 1909. 



c. d. (J ? nestling. Colonia Risso, Paraguay. Sept. 9, 

 1909. 



e. (^ ad. Near Puerto Braga, Paraguay. Sept. 24, 1909. 



f,g,h. ? ad. „ „ „ Sept. 24, 1909. 



i. ? juv. „ „ „ Sept. 24, 1909. 



./, k, L S ad. Colonia Risso, „ Oct. 26, 1909. 



This Tern was very plentiful on both the Parana and 

 Paraguay Rivers, and was observed as far south as Parana, 

 but not below\ 



It was especially common on the Rio Paraguay as far north 

 as we went; and breeding colonies were observed or visited 

 on the 9th, 10th, 24th, and 29th of September, and on the 

 return southwards these were noted or visited again on the 

 14th and 26th of October. 



The first colony was visited on the 9th of September, when 

 this species was found breeding in company with Rhunchopis 

 melanura and Sterna superciliaris. 



The Skimmers and Great-bills were nesting together at one 

 end of a long sand-bank and the Terns {Sterna superciliaris) 

 were in a small colony of their own at the otlier end, where 

 there was a little rough grass growing. 



When we went ashore the Terns flew right away, the Skim- 

 mers flew round and round the bank out over the water in 

 ])airs, uttering their single mournf nl cry ; but they were most 

 aggressive, a flock of many hundreds keeping us companv, 



2k2 



