NATURAL SCIENCES OF PHILADELPHIA. 
539 
Sterna regia, Gambel, Pr. A. N. S. Ph. iv. 1848, 128. 
Thalasseus regius, Id, J. A. N. S. Ph. i. 2 d ser. 1849, 228. 
Diag. — Thai, rostro magno, robusto, nec peracuto, aurantio-rubrp ; remige 
prima interne alba nec ad apicem extensii marginata; pedibus nigris, medio 
digito cum ungue non tarso breviore. Long. rost. 2*60 poll. ; aim 14-50 ; tarsi 
1-30. 
Habitat. — South Atlantic Coast of America ; Antilles in winter. California. 
A good series of this bird, collected in Jamaica, enables me to give its winter 
plumage, as well as that of the young of the year. 
Winter Plumage. — Bill less brightly colored than in summer, its tip and cut- 
ting edges dull yellowish. Front white, crown variegated with black and white, 
the former color increasing on the occiput and nuchal crest, which latter, 
though shorter than in summer, is almost or quite unmixed with white. This 
black extends forwards on the sides of the head to the eye, which it includes. 
The tail is not pure white, as in summer, but is glossed over with the bluish of 
the mantle, which deepens towards the tips of the feathers into dusky plum- 
beous. Otherwise as in summer. 
Young of the Year in August. — Bill considerably smaller and shorter than in 
the adult; its tip less acute, and its angles and ridges less sharply defined; 
mostly reddish- 3 -ellow, but light yellowish at tip. Crown much as in the adults 
in winter; but the occipital crest scarcely recognizable as such. Upper parts 
mostly white; but the pearl-gray of the adults appearing in irregular patches, 
and the whole back marked with small, irregularlv-shaped, but well-defined 
spots of brown. On the tertials the brown occupies nearly the whole of each 
feather, a narrow edge only remaining white. Lesser wing coverts dusky 
plumbeous. Primaries much as in the adults, but the line of demarcation of 
the black and white wanting sharpness of definition. Tail basally white, but 
soon becoming plumbeous, then decidedly brownish, the extreme tips of the 
feathers again markedly white. Otherwise as in the adults. 
The species is so distinct from any other of North America, that it hardly 
requires comparison. Caspius is most closely allied (except elegans ) and has 
been confounded with it. But the differences between the two are very great. 
Regius is a much smaller bird, its wing two inches or more shorter. The bill 
is nearly or quite as long, but it is much slenderer and every way weaker. The 
tail is very decidedly longer and more forked, almost equalling in this respect 
elegans or acuflavidus. The feet, with the same relative proportions of tarsus 
and toes, are proportionally shorter. In color the two are quite similar, except 
in the primaries where a very marked difference is observable. The inner webs 
of caspius are wholly dull hoary plumbeous ash ; while the inner web of 
regius has a very sharply defined white margin, as in elegans or acuflavidus , and 
Sternse generally. 
But while there is thus no difficulty in separating it from its North American 
allies, the case is quite different from the Central and South American species, 
with which it is more or less intimately related. It was, up to 1848, confounded 
with S. cayana, Lath. ( S . cayanensis, Gm.) This error was first corrected by 
Gambel ( 1 . c.), and a distinct name imposed. It is difficult, perhaps impossi- 
ble, to determine to what species Latham’s name is to be referred. ITis brief 
diagnosis is “ St. grisea, pennis rufo-marginatis, occipite nigro, corpore subtus 
albo. Habitat in Cayana. 16 pollices longa.” This description is evidently 
that of a young bird. Gambel is inclined to consider it as “ the immature 
plumage of one of the yellow-billed species of the Brazilian coast, figured 
by Lichtenstein, probably S. magnirostris .” He further remarks that “ young 
birds of our species would agree pretty well with the eryihrorhyncha , of De 
Weid, as they are somewhat smaller and less proportioned.” 
There is a specimen in the Smithsonian collection, presented by Mr. Sclater, 
from Jamaica. It was killed March 23d, and is in moult; probably, a young 
bird putting on its first spring livery, though still retaining its winter marks of 
1862.] 
