LARIDif: — THE GULLS AND TERNS — STERNA. 275 



— one was certainly obtained in the Galapagos, and not within our limits; and as 

 the expedition that procured the supposed Californian example visited the same 

 group, Mr. Salvin is of the opinion that this was the locality from which both speci- 

 mens came, and that this bird does not belong to the fauuc., of the United .States. 



Genus STERNA, Linn.isus. 



Sterna, Lixn. S. N. eu. 10, I. 17.58, 137, ed. 12, I. 17C6, 227 (type, by dim., Steriui hincndo, Li.vx.). 



Sternula, BoiE, Isis, 1822, 563 (type, Sterna minuta, Linn.). 



Thalasscus, BoiE, Isis, 1822, 563 (type, Sterim casinu, Pall.). 



Thalassea, Kaup, Sk. Eiitw. Eur. Tliieiw. 1829, 97 (type. Sterna 2)aradisca, Bkunn.). 



Sylochelidon, Bi'.ehm, Vog. Deutschl. 1830, 767 (type. Sterna casjna, Linn.). 



ActocJich'don, Kaut, Sk. Ent. Eur. Thierw. 1829, 31 (type, Sterna cantiaca, Gmel. ). 



Gelochelidon, Buehm, Naturg. Vog. Deutschl. 1831, 774 (type, G. mcridlmialis, Biieu.m, Sterna 



anglica, Mont. ) . 

 Haliplana, Wagl. Isis, 1832, 1224 (type, Sterna fulujinosa, Gmel.). 



Char. Size exceedingly variable, the form and colors less so ; tail always decidedly forked, 

 and toes almost fully webbed, but tlie webs concave, or " scalloped out," anteriorly. 



Synopsis of North American Species. 



A. Size medium (wing about 11.75-12.25 inches) ; tail emarginate ; occipital feathers soft and 



blended ; inner webs of primaries bicolored (a blackish stripe next the shaft, the inner 

 border broadly white) ; bill wholly black, short and thick, its upper and lower outlines 

 strongly convex, the depth through the base about one third the length of the culmen ; 

 pileum entirely black in summer, uniform ashy white in winter. (Gelorlulidon, Brehm.) 



1. S. anglica. Bill and feet black : above, pale pearl-blue, including the rump, upper tail- 



coverts, and tail ; beneath, entirely white. Wing, 11.75-12.25 inches ; tail, 5.50 ; culmen, 

 1.40 ; tarsus, 1.30 ; middle toe, 1.10. Hob. Eastern coast of North America, and various 

 parts of the Old World. 



B. Size very large (wing 15.00 inches or more) ; tail emarginate ; occipital feathers soft and 



blended, not forming a crest ; inner webs of primaries concolored (dusky grayish) ; adult, 

 above, pale pearl-gray, l^eneath, white ; hood wholly black in summer, wholly streaked or 

 speckled with white in winter. (Thalasseus, BoiE.) 



2. S. caspia. Bill very robust (the depth through the base a little less than one third the 



length of the culmen), deep red. Hub. North America iii general, and various parts 

 of the Old World. 



C. Size large or medium (wing 12.50-15.00 inches) ; tail deeply forked ; occipital feathers pointed 



and somewhat lengthened, forming a short but distinct crest ; inner webs of primaries 

 bicolored (dusky in a well-defined stripe next the shaft, the inner edge brvidly and 

 abruptly white) ; adult, pale pearl-gray above, white beneath ; pileum wholly black in 

 spring, the forehead, lores, and centre of the crown white in breeding-season. (^Actoclicl- 

 idon, Kaup.) 



3. S. maxima. Bill stout (depth through the base much less than one third the length of 



the culmen), deep orange ; wing, 14.00-15.00 inches. Hah. Coasts and inland waters 

 of Middle and Southern North America, north to about 40°. 



4. S. elegans. Bill very slender (depth through the base about one fifth the length of the 



cuhueii), deep orange-red ; occipital feathers much elongated, and lower parts deeply 

 tinged with ptach-blossom pink. Wing, about 12.50 inches. Ifab. Pacific coast of 

 Middle America, north to California. 



5. S. sandvicensis. Bill very slender, as in S. elegans, but deep black, tipped with yellow ; 



occipital feathers less elongated, and lower parts without pink tinge. Wijig, about 12.50 

 inches. Hab. Atlantic coast of North, and both coasts of Middle, America ; Palcearctic 

 Region. 



