BIRDS OF NORTH AND MIDDLE AMERICA. 467 



Range. — Cosmopolitan, in warmer regions, mostly on sea-coasts. 

 (About seven species, four of them American.) 



KEY TO THE SPECIES OF TIIALASSEUS (ADULTS ONLY). 



a. Bill red or yellow. 

 6. Larger {wing 358-393); bill red. (Coasts of United States, northward regularly to 

 Virginia and California; southward to Brazil and Peru; also west coast of 



Africa in winter.) Thalasseus maximus (p. 467). 



hh. Smaller (wing much less than 350). 

 c. Bill orange-red ; gonydeal angle far anterior to nostril. (Pacific coast of America 



from California to Chile.) Thalasseus elegans (p. 472). 



cc. Bill lemon yellow; gonydeal angle very little anterior to nostril. (Atlantic 

 coast of South America, from Venezuela to Patagonia.) 



Thalasseus eurygnathus (p. 474). 



aa. Bill black, usually tipped with yellowish or whitish. (Thalasseus sandiicensis.) 



b. White edging to three or four outer primaries much wider, extending quite to 



tip; wing and tail averaging decidedly longer? (Western and southern Europe 



and eastward to Caspian Sea; south in winter to Persian Gulf and Cape of 



Good Hope.) Thalasseus sandvicensis sandvicensis (extralimital).o 



bb. Wliite edging to three or four outer primaries much narrower, usually not 

 extending to tip, which is occupied by an extension of the dark gray inner 

 stripe; -ndng and tail averaging decidedly shorter? (Southern Atlantic and 

 Gulf coasts of United States and Mexico; in winter, both coasts of Mexico 

 and Central America, Bahamas, Greater Antilles, and southward to Brazil and 

 Colombia.) Thalasseus sandvicensis acuflavidus (p. 476). 



THALASSEUS MAXIMUS (Boddaert). 



ROYAL TERN. 



Adults in hreedingO) plumage (sexes alike). — ^Entire pileum, includ- 

 ing occipital crest, nape, and upper half of lores, uniform deep black; 

 rest of head and neck, under parts, rump, upper tail-coverts, and 

 edge of wing immaculate pure wliite; back, scapulars and wings pale 



"■[Sterna] sandvicensis Latham, Gen. Syn., Suppl. i, 1787, 296 (Kent, etc.). — [Sterna] 

 cantiaca Gmelin, Syst. Nat., i, pt. ii, 1789, 606 (near Sandwich, England ; based on Sand- 

 wich Tern Latham, Synop., \d, 356; etc.). — Sterna cantiaca Temminck, Man. d'Orn., 

 1815, 479; Werner, Atlas, PalmipMes, 1828, pi. 3; Gould, Birds Em-., v, 1837, pi. 415 and 

 text; Naumann, Vog. Deutschl., x, 1840, 50, pi. 250; Schlegel, Vog. Nederl., 1854, 

 611, pi. 359; Sclater and Salvin, Proc. Zool. Soc. Lond., 1871, 569, part (monogr.); 

 Saunders, Proc. Zool. Soc. Lond., 1876, 653, part (monogr.); Cat. Birds Brit. Mus., 

 XXV, 1896, 75, part; Dresser, Birds Europe, viii, 1877, 301, pi. 586. — Thalasseus can- 

 tiacus Boie, Isis, viii, 1822, 563. — Thallasseus cantiaca Boie, Isis, viii, 1822, 880. — 

 Actochelidon cantiaca Kaup, Natiirl. Syst., 1829, 31, 196; Gould, Birds Great 

 Brit., V, 1873, pi. 69 and text.— Thalasseus cantianus Brehm, Naumannia, 1855, 

 295. — [Sto-na] boysii Latham, Index Orn., ii, 1790, 806 (new name for S. cantiaca 

 Gmelin). — Ster7ia boysii Temminck, Cat. Syst.-, 1807, 184. — Sterna stubberica Otto, 

 in German ed. Buffon's Hist: Nat. Ois., xxx, 1790, 104. — (?) Sterna columbina 

 Schranck, Fauna Boica, i, 1798, 232. — Sterna canescens Meyer and Wolf, Taschenb., 

 ii, 1810, 458. — Thalasseus canescens Brelim, Vog. Deutschl., 1831, 776. — Thalasseus 

 candicans Brehm, Vog. Deutschl., 1831, 777. — Thalasseus pauli de wurlemberg 

 Brehm, Vogelf., 1855, 346 (Greece). — Sterna sandvice^isis sandvicensis Baird, Brewer 

 and Ridgway, Water Birds N. Am., ii, 1884, 289, footnote (ex Sterna sandvicensis 

 Latham, Synop. Suppl., i, 1787, 296); American Ornithologists' Union, Check List, 

 1910, 43. 



