fj. STEKNA. 



131 



leiij^th 14 inches, culnicn 1-8, wing 10'25, tail 5'75, depth of fork 

 2'S, tarsus U'U5, middle too with claw I'l. 



Adult in winter. Like the above, oxcei)t that the black of the 

 orbits aud auriculars is paler and little more than iron-grey. The 



primaries are then new, beautifully frosted, and have a very silvery 



^.a ppe arance. 



Immature. Very similar, but the centres of the long inner second- 

 aries are ash-grey. At an earlier stage, the eye-streak is more 

 developed and blacker ; the webs of the outer primaries are brownish 

 black on both sides of the shafts owing to the wear of the frosting ; 

 the und^rparts are white ; and the bill is dull ochre-brown at the 

 base, though yellow at the tip. 



Young. The patch before and the streak behind the eye decidedly 

 larger, and there is an indication of a greyish crescent on the nape ; 

 the crown greyish white, slightly mottled with brown, as 'are the 

 feathers of the mantle ; tail-feathers dark ash-grey with white 

 margins : bill yellowish brown at the base, the rest blackish, with 

 no yellow at the tip ; tarsi and toes yellow. 



In its immature and young plumage this Tern resembles S.forsteri, 

 but the latter always shows more distinct coloration on the crown 

 and nape, while its hind toe is decidedly shorter, and its bill has 

 no yellow at the tip. 



Hah. East coast of South America from llio de Janeiro to 

 Argentina ; also on the West side, in Chile, up to Arica (which was 

 formerly in Peru). Accidental in the United States (Long Island 

 and New Jersey [?]). 



a. 5 imm. sk. Rio de Janeiro, Aug. (H. M. H. Saunders Coll. 



Harrison, R.N.). 

 b,c. cJ 5 ad. sk. Santa Catharina, S. Brazil, H. Saimders Coll. 



Aug. 188.3 {H. M. Harrison, 



R.N.). 

 d,e. Vix ad.;-/, Santa Catharina, S. Brazil {H. H. Saunders Coll. 



y. Imm. sk. Rogers). 



h, i. Yix ad. sk. Santa Catharina, S. Brazil {H. Salvin-Godman Coll. 



Rogers), 

 k. 2 juv. sk. Maldouado, Uruguay, Jan. (H. H. Saunders Coll. 



M. Harrison, R.N.). 

 I. Ad. sk. Punta Lara, Argentina, Oct. H. Durnford Coll. 



(H. D.). 

 m. $ ad. sk. Buenos Ayres Prov., Sept. {H. H. Durnford Coll. 



n. Ad. sk. . Buenos Ayi-es Prov. Alan Peel, Esq. [C.]. 



0. (5" ad. sk. Buenos Ayres Prov., Nov. (^m;-- Salvin-Godman Coll. 



meister). 



p, q. S ad. sk. Ajn, B. A. Prov. {E. Gibson). H. Saunders Coll. 



r. Ad. St. Chile {Bridges). Purchased. 



«. Ad. St. Chile (Cuming). Purchasied. 



