552 
PROCEEDINGS OF THE ACADEMY OF 
Sterna antillarum Coues ex Lesson. 
Sterna minuta , Wilson, 1813; Bonaparte, 1828; Audubon, 1838; sed non Lin- 
nsei, 1776. 
Sterna argentea , Nuttall, Man. Orn. 1834, ii. 280; sed non Princip. Maxim, qum 
species Braziliensis. 
Sterna frenata, Gambel, Pr. A. N. S. Ph. 1848, iv. 128. 
Sternula antillarum , Lesson, Descriptions de Mammiferes et d’oiseaux recemment 
de couverts, &c., Paris, 1847, p. 256. Adultus. 
Sternula melanorhynclia. Lesson, op. et loc. cit. Juvenis. 
Diag. — S. Sternse minutce similis, ejusdemque statu rae ; sed rostro breviore et 
valdk graciliore, vitta frontale angustiore, dorso, uropvgio, caud&que supra con- 
coloribus, ccerulescentibus-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 marked 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 adhlt 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. Ic 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 adute 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. 
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