BIBDS OF NORTH AND MIDDLE AMERICA. 485 



Genus STERNA Linnaeus. 



Sterna Linnaeus, Syet. Nat., ed. 10, i, 1758, 137; ed. 12, i, 1766, 227. (Type, as 



designated by Gray, 1840, Sterna hirundo Linnaeus.) 

 Onychoprion Wagler, Isis, xxv, 1832, 277. (Type, by monotypy. Sterna serrata 



Wagler =./uscata Linnseus.) 

 Chelidoa Billberg, Synop, Faunae Scand., i, para 2, 1828, tab. A and p. 193. (New- 

 name for Sterna Linnaeus.) 

 Planetxs Wagler, Isis, xxv, 1832, 1222. (Type, Sterna guttata Wagler ex Forster, 



manuscript, =S. fuscala Linnajus.) 

 Planetes (emendation) Gistel, Naturg. Thierreichs fiirhohere Schulfen, 1848, p. x. 

 Haliplana Wagler, Isis, xxv, 1832, 1224. (Type, Sterna fuliginosa Gmelin= 



S.fuscata Linnaeus.) 

 Melanosterna b Blyth, Journ. Asiat. Soc. Bengal, xv, 1846, 373. (Type, Sterna 



anxlhetus Scopoli.) 

 Thalassipora "Boie" Ruppell, Syst. Ueb. Vog. Nord-ost-Afrika, 1845, 140. 



(Type. Sterna infitscata Lichtenstein=AS'. fuscata Linnaeus). 

 Dipsaleon Gistel, Naturg. des Thierreichs fiir liohere Schulen, 1848, p. x. (New 



name for Planetis Wagler.) 



Medium-sized to rather small Sternidse (wing about 210-300 mm.) 

 with tail more than half as long as wing, deeply forked and with 

 lateral rectrices attenuated (sometimes subacummate) terminally, 

 and occipital feathers normal (short and blended). 



Bill about as long as head, moderately slender, its greatest depth 

 nearly equal to half the distance from anterior end of nostril to tip of 

 maxilla, the more or less prominent gonydeal angle usually about 

 midway between tip of mandible and malar antia, rarely anterior to 

 the middle, more often decidedly posterior to the middle; nostril 

 narrowly oval, elliptical, or linear, always separated from the latero- 

 frontal antia, but width of intervening space variable. Wing long 

 and pointed, the longest primary (outermost) exceeding distal 

 secondaries by at least twice the distance from tips of the latter to 

 bend of wing (except in S. melanogastra) . Tail much more than half as 

 long as wing, forked for more than half its length (except in S. melanau- 

 chen) f the lateral retrices more or less slender and attenuated (some- 

 times sub-acuminate) terminally. Tarsus sometimes longer, some- 

 times shorter, than middle toe without claw; webs with anterior 

 margins moderately excised. 



Plumage and coloration. — Occipital feathers normal (short and 

 blended), except in S. melanauchen.'^ Adults with at least part of 

 pilcum and nape.uuiform black (except in S. trudeaui) sometimes with 

 a white frontal crescent, one species (S. melanauchen) '^ with only the 

 nape and a stripe through the eye black; rest of upper parts plain 

 gray (more or less deep) to sooty black; under parts white or gray, 



o '■* ... graecum XeXiSw, Hirundo marina, conservavimus." (Billberg.) 



6 MeXas (/leXav-), black; -\-Sterna. (Richmond.) 



<^S. vielanauchen should probably be separated generically. 



