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. 2d ser. 1849, 228. 



Diag. Thai, rostro inagno, robusto, nee peracuto, aurantio-rubro ; remige 

 prim;! interne alba nee ad apicem extensil marginata ; pedibus nigris, medio 

 digito cuoi ungue non tarso breviore. Long. rost. 2-60 poll. ; ate 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 riumage. 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 

 biack 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 aad shorter than in 

 the adult; its tip less acute, and its angles and ridges less sharply denned; 

 mostly reddish-yellow, 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, irregularly-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 

 Sterrue 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. (5. caya?iensis, 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. His 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 eryihrorhy7icha, 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.] 



