NATURAL SCIENCES OP PHILADELPHIA. 549 



For a species so long known, the present has remarkably few synonyms. That 

 of S. Wilsoni is the one which has been most firmly established. I quote S. 

 flaviatilis with a query on the authority of Temminck. This author, and also 

 Degland, unhesitatingly refer it to the present species, while by some very re- 

 cent authors* it is regarded as distinct. Eyton, in calling the bird S. marina, 

 derives his authority for the specific name from the Hirundo marina, of Ray's 

 Synopsis, p. 131. Brisson's Sterna major probably also refers to this species, 

 but though both these latter names have priority over Linnaeus' appellation, 

 they are to be disregarded, as neither of their authors were binomalists. 



Sterna macroura Naumann. 



Sterna hirundo, Faber, Prod. 1822, p. 88. Fabricius, Faun. Grcenl. 1780, p. 



105. Nee Linn, nee Richards. 

 Sterna macroura, Naum., Isis, 1819, p. 1847. Degland, Ornith. Europ. 1840, 



p. 344. Lawrence, Gen. Rep. Birds, 1858, p. 862. 

 Sterna arctira, Temm., Man. Orn. 1820, ii., 742, et auct. pleriq. 

 Sterna nitzschii, Kaup, Isis, 1824, p. 153, secundum Gray. 

 ? Sterna brachytarsa, Graba, fide Gray. 



Diag. St. rostro gracile, rubro ; pedibus brevissimis, rubris ; corpore toto 

 caerulescente-plumbeo, subtus dilutiore; cauda, uropygio, tectricibusque 

 caudalibus inferioribus albis ; rectrice laterali valde elongata, pogouio ex- 

 terno griseo-fusco. 



Habitat. Europe. Atlantic Coast of North America from Massachusetts 

 northward. Interior of Arctic America, (Hudson's Bay, Great Slave Lake.) Semi- 

 avine Straits. 



Examination of a very large series of this species shows it to be subject to 

 great variations in some respects. These are especially noticeable in the bill 

 and tail. The largest bill in the series measures 1-40 inches along the culmen ; 

 the smallest (from Nova Scotia) only 1-08, the difference being over -30 of 

 an inch. The average length of bill is about 1-30. The tail varies in length 

 quite as remarkably, the difference between two equally adult individuals being 

 more than \\ inches. The color of the bill is pretty constant, a uniform deep 

 lake. Sometimes, however, it acquires a dusky tip, but never the decided black 

 space which exists in S. hirundo and Forsteri. The bill is much smaller, and 

 every way more delicately shaped than in those species. The under parts are 

 nearly uniform in color. This is very decided, scarcely if at all lighter than 

 the back, (very different from the slight wash of hirundo,) and extends in full 

 intensity quite from the throat to the vent, the under tail coverts being pure 

 white, in marked contrast. The under surface of the wings do not share the 

 general color of the body, but are pure white. The feet are exceedingly short, 

 and hardly vary appreciably. Their color is carmine, not so deep as the bill, 

 but still not of the vermilion or coral red of those of hirundo. 



The distinctive features of this species and the S. hirundo, will be found under 

 the head of S. Forsteri. They are so many, and so well marked, that it is difficult 

 to conceive how the two species were ever confounded. The differences between 

 it and S. Pikei, the next most closely allied species, are given under the head of 

 the latter. There is no other North Americau species with which the present 

 requires comparison. 



I have carefully examined a large series of examples from both continents, 

 and have been unable to detect the slightest discrepancies. This is one of the 

 species of which, so far as I am aware, American and European specimens have 

 never been separated by any writer. 



Temminck's name of arctica has until recently been very generally applied to 

 this bird ; but that of Naumann must supersede it. Temminck admits that 

 Naumann named the bird macroura before he called it arctica, but insists upon 



* De8 Murs. Traite Generate d'Oologie Ornithologique, p. 551. 



1862.] 



