(5, STERNA. 



125 



Hartl. Ind. Azara, p. 26 (1847) ; Burm. Th. Bras. iii. p. o42 



(1856); id. Reis. La Plata-St. ii. p. 419 (1861); Pelz. Oni. Bras. 



pp. 325, 461 (1871). 

 Sternula argentoa, Buie, Isis, 1844, p. 183 ; Licht. Noynencl. Av. p. 'J8 



(1854: IJrazil). 

 Sternula siiperciliaris, Boie, Isis, 1844, p. 183. 



Adult in hrcedlnif-phanar/e. Like the preceding species, but larger 

 and stouter ; the black loral streak very narrow ; the mantle and 

 tail darker grey, with a slightly brown tinge on the inner second- 

 aries ; the four outer pairs of primaries cliiotly dusky black, with 

 comparatively narrow white margins to tlie inner webs of the two 

 first, and very little white on the next two pairs inwards : bill stout 

 and deep at the base, greenish yellow, with no black at the tip ; 

 tarsi and toes dull yellow or olivaceous. Total length only 1) inches 

 (owing to the tail being short), culmen 1-5, wing 7"25, tail 3-2.5, 

 depth of fork 1-3, tarsus 0-65, middle toe with claw 0-75, Ttie 

 sexes appear to be alike in plumage. 



Adult after the autumn moidt. Lores merely speckled with black • 

 crown flecked with white ; otherwise like the above. 



Immature. Lores and forehead white ; crown grey, with blackish 

 streaks which become confluent round the eye and on the nape ; 

 primaries with a brownish tinge : bill yellow, with horn-coloured 

 tip. Otherwise like the adult. 



Young. Lores drab, a very marked whitish superciliary streak, 

 forehead drab ; crown darker, flecked with umber ; a black patch 

 from behind tbe eye to the nape ; mantle grey, tinged with buff 

 and barred with ash ; tail mottled with ash, the ground-colour 

 greyer than in any of the allied species : bill dull yellow, the maxilla 

 nearly horn-colour ; tarsi and toes dull yellow. Conspicuously 

 darker than tlie young of S. antillarum. 



Hub. Estuaries and rivers of South America from the Orinoco to 

 the La Plata, ascending the Amazons and tributaries as far west as 

 the river Huallaga. Eggs laid on sand-banks. 



a. 2 juv. ; 



f>,c. (S 2 ad. sk. 



d. 1mm. sk. 



e. Ad. st. 



f. Imni. sk. 

 ff. cJ iium. sk. 

 h. Ad. sk. 



i. cJ ad. sk. 



/. 6 



k. 2 imm 



ad. sk. 



m, n. Ad. sk. 



0. (S imm. sk. 



Vix ad. sk. 



Rupuruni River, Brit. Guiana, 



Nov., Dec. (H. Whiteh)). 

 Surinam, Dutch Guiana {iJr. 



W. Kirke). 

 Amazons. 



Amazons ( Wtdlncc ^- Bates). 

 Amazons (A. Ii. Wallace). 

 Tocantins liiver,Lnwer Ama- 

 zons, Sept. (A. Ii. ir.). 

 Santa Cruz, Upper Amazons, 



May {E. BartMt). 

 Rio de Janeiro, July {J. 



YoumJ). 



Sao Paulo, Brazil {Nattercr). Salvin-Godman Coll 

 Colonia, Rio de la I'lala, II. Saunders Coll. 



Nov. {U. M. Harrison, 



B.N.). 

 Baradero, River Parana, H. Dnruford, Esa 



April. [C.]. ^ 



Salvin-Godman Coll. 

 H. Saunders Coll. 



Purchased. 

 Salvin-(Todman Coll. 

 Salvin-Godman CoU. 



H. Saunders Coll. 



II. Saunders Coll. 



