552 PROCEEDINGS OP THE ACADEMY OP 



Sterna antillarom Coues ex Lesson. 



Sterna minuta, Wilson, 1813; Bonaparte, 1828; Audubon, 1838; sed non Lin- 



naei, 1116. 

 Sterna aryentea, Nuttall, Man. Orn. 1834, ii. 280; sed non Princip. Maxim, quae 



species Braziliensis. 

 Sterna frenata, Garabel, Pr. A. N. S. Ph. 1848, iv. 128. 

 Stei-nula antillarum, Lesson, Descriptions de Mammiferes et d'oiseaux recemment 



de couverts, &c, Paris, 1847, p. 256. Adultus. 

 Sternula melanorhyncka. Lesson, op. et loc. cit. Juvenis. 



Diag. S. Sternse minutes similis, ejusdemque statural; sed rostro breviore et 

 valde graciliore, vitta frontale angustiore, dorso, uropygio, caudaque supra con- 

 eoloribus, coerulescentibus-perlaceis. 



Habitat. Atlantic coast of North America, from Labrador to Texas, and 

 ranging further south into the Antilles. Great lakes and rivers of interior of 

 North America. Not on the Pacific coast ? 



The bill of this species, as usual in the subfamily, varies somewhat in length ; 

 but the longest bills before me do not equal the shortest of the European bird. 

 The slenderness of the bill, which is very tuarked in comparison with its trans- 

 atlantic congener, is constantly preserved. The black tip of the bill, usually 

 from one and a half to two-tenths of an inch in length, is sometimes reduced to 

 a mere point ; but it is very rarely wanting altogether. The white frontal lunula 

 varies within narrow limits, probably widening somewhat with increasing 

 age: but it never, I believe, attains the ordinary breadth of that of the Euro- 

 pean. The neck behind, between the black pileum and the back, is a somewhat 

 lighter shade than the latter, but the difference is scarcely noticeable. The 

 pearl gray of the back and wings extends unchanged on the rump, upper cov- 

 erts, and the inner tail feathers quite to their tips; but the outer vanes of the 

 lateral tail feathers, and their bases, are white. As described by most authors, 

 the two outer primaries in the great majority of adult spring birds are black, 

 their shafts white, their inner webs broadly bordered with white, except toward 

 the tips; but specimens frequently occur which have the three or four outer 

 primaries of this color. This is, without doubt, merely a seasonal feature, and 

 one quite independent of sex or age ; for all the specimens bearing this char- 

 acter of primaries are adult birds, labelled as having been taken in July and 

 August. At this season of the year they have finished the duties of incubation, 

 and are about to put on the perfect winter dress, as the ragged and dilapidated 

 condition of their plumage testifies. It is well known that allied species of 

 Terns, such as S. hirundo, Forsteri, etc., towards the close of the summer, at the 

 approach of the moult, entirely lose the delicate silvery hoariness with which 

 the primaries are glossed over during the breeding season these parts becom- 

 ing of a plain, dull, brownish tint. The change in the present species is pre- 

 cisely analogous. 



The young of the year, taken in July and August, differ greatly from the adults. 

 The bill, though as stout at the base, is much shorter, less acute at the tip, and 

 wants the sharply -defined angle at the symphysis. It is brownish black, the 

 base of the under mandible dusky flesh color. The forehead is mostly white. 

 The crown and occiput are variegated with brownish black and white, the for- 

 mer color mostly aggregated into a postocular patch. The back and wing cov- 

 erts are lightly washed over with the pearl gray of the adults ; but this color is 

 greatly obscured, and its continuity interrupted by dark brown crescentic or 

 hastate spots, one or more on each feather, which give the upper parts a mottled 

 appearance. The primaries are all grayish black, growing successively lighter, 

 and more and more glossed with silvery, from without inwards ; the inner webs 

 of all bordered with white. This white is broadest on the outer primary, but 

 falls considerably short of the tip ; it grows narrower, but at the same time 

 longer, on the others, until on the inner ones it goes quite around the tip to the 



[Dec. 



