NATURAL SCIENCES OF PHILADELPHIA, 
551 
The tail is very long. I do not mean, however, that the lateral tail feathers 
are greatly produced, as in macroura and paradisea, (though that is not improbably 
the case in the summer plumage) for the depth of the fork is not greater com- 
paratively, than in hirundo ; but the whole tail is produced, the central feathers 
being absolutely as long as in macroura , which is a larger bird. The outer web 
of the lateral tail feather is very dark colored, — even more so than is that of 
macroura, — and the outer webs of the other feathers are shaded with grayish ; 
but in the adult it is probable that the colors will be the same with those of the 
last-named species. A striking feature of PiJcei is the pure white of the whole 
under parts, of the rump, and of the neck behind between the black pileum and 
the back, there being not the slightest trace of the plumbeous wash, so conspic- 
uous in macroura, hirundo , etc. The species in this respect agrees with S. para- 
disea, and, like that species, may perhaps, during the breeding season, acquire 
a rosy tint on the under parts. 
I regard this species as intermediate between S. macroura and paradisea , 
though most closely allied to the former. In the foregoing remarks the differ- 
ences between the two have been pointed out. With the latter- — S. paradisea — it 
agrees in several particulars : slenderness of bill, color of under parts and of 
feet, &c. It is at once to be distinguished by its much darker colored upper 
parts, different markings of primaries, pure white rump, slenderer and smaller 
bill and feet, greater elongation of central tail feathers, &c. 
The acquisition of perfect specimens of various stages of this interesting Tern, 
of whose changes of plumage we can only judge by analogy, and with whose 
habits we are entirely unacquainted, is a particular desideratum in North Amer- 
ican Ornithology. 
Sterna paradisea Briinn. 
Sterna paradisea, Brunnich, Orn. Bor. 1764, p. 46, and of recent authors. Law- 
rence, Gen. Rep. 1858, 863. 
Sterna Dougalli, Montagu, Orn. Diet. Suppl. 1813, and of most authors, inclu- 
ding Audubon ami Nuttall. 
Sterna Macdouyalli, Macgillivray, Man. Orn. ii. p. 233. 
Thalasssea Dougalli , Kaup. 
Ilydrocecropis Dougalli, Boie, Isis, 1844, p. 1-79. 
DiAG. — (nupt. temp, ad.) S. rostro tenue, nigro, basin versus rubescente, 
pedibus rnbro-aurantiis ; cauda longissima, valde forfieata, fere albida, remigi- 
bus omnibus interne albo-marginatis ad apices ipsas ; corpore supra perlaceo, 
subtus rosaceo-albo. * 
Habitat . — Atlantic coasts of Europe and America. 
In a number of equally adult examples, I find that the color of the bill varies ; 
in most the black extends nearly or quite to the base, in others fully the basal 
7" ^ third of the bill is reddish^ The extreme points of both mandibles arq yellow- 
ish. The color of the mantle is lighter than that of any other species ; the 
tail, exceedingly long and tapering, is of so light<a 'pearly^blue as to be almost 
white. A most striking feature of coloration of this species consists in the 
well-defined, broad white inner margins of all the primaries extending quite 
around the tips of the feathers, on to the outer webs on the first and second 
primaries. Immature and winter specimens have the bill brownish black ; the 
front white; the crown and nape dull black, variegated with white. The lateral 
tail feathers want the great elongation and attenuation they acquire during the 
breeding season, the tail being no more deeply forked than that of Forsteri, or 
even of hirundo. 
This species is so distinct in characters, that a comparison with any other is 
needless. 
The American bird has never, I believe, been separated from the European. 
The specimens I have compared appear identical in every respect. 
1862 .] 
