686 STERNA MACRUKA, ARCTIC TERN 



Sterna argmlata, Brehm, Bcitr. iii, lS'2i. (i93; V. D. 1831, 'S-2, pi. H8, fig. r.. 

 Stvrna ariiaiiacva, Bumm, V. D. lH;n, 7s:t. 



Stmia iiitzKchii, Kxvv, Isis, 1H2I, K.:!.— Bukiim, V. D. IKU, 781!.— Hi-., C. IJ. 18r>(i, 772. 

 Siena hrachijlmsa, GIUUA, lieiso naob Faidc, 1830, ai8. 

 Ktiriiu hriwhypus, SwAlNsoN, B. \V. Afr. ii, 1837, 2.V2. 

 Skrnn oocviiiciroHlris, Khicti. {fide CJuay). — Bp., Compt. IJciul. IKM, 77,*. 

 Stcnia piled, L\\\ii., Aun. h\v. N. Y. vi, 18,'-i3. 3 ; B. N. A. 18r.8, S,-,;i, pi. il.'i.— Br., Ooiupt. 

 Roud. 1856, 172 {" i'i!ihii").—CovKf^. \'r. I'liila. Acud. 18««, iM). 



DiAQ. SI. rostro i/raeilc, riihro ; pcdihiin brfinHnimin, riibrin ; covimni c(vnilin('ciilc-iiliiiiilwo, 

 auhlua liiUition' ; ckhiW, uropjiijio, iiolrivihiisniiv miiiiulihim iiiftnoribm albia ; iri'iriir 

 lulcrali valdd elongatd, pogonio vxlvrno grimv-fiiniv. 



Bab. — Europe. Asia. Afiica. North America generally, Bouth to tli(> Middle States, 

 and on tlie raciflo side to California. Breeds from Massacbusetts northward. No valitl 

 extniliniital record south of the United States; compare, however, PlULUi'i'i, Cat. I8(i',), 

 49 (Chili II?). 



Adult ill breeding ptumage. — Bill shorter than tho head, equal to the middle toe and 

 taiHus together, slender, compressed, acute. Cnlmeu somewhat broad and flaltish 

 toward the base, more compressed niul narrower anteriorly; about straight to be.voiid 

 the nostrils, declinato-convex for the rest of its length. Connuissnre very sliijiitly 

 curved. Gonys about as long as the rami ; perl'eetly straight ; the outline of the latter 

 a little concave. luter-crnral sjiace very narrow; about half filled with foatheis. 

 Nasal groove rather long, but becoming obsolete before it reaches th(> toiuia. A quite 

 prominent stria jiroeeeds from its anterior extremity totbetomia, bnt little behind the 

 tip of the bill. Tho bill is deep carminti, or lake red ; usually without any bhieli, but 

 this color sometimes ajipoars in a limited degree. 



The feet are remarkably small and weak. Tho tibia< are bare for a moderate dis- 

 tance. The tarsi are exceedingly short, being less than the middle toe without its 

 claw, or, at least, only eijual to it. The toes are rather long for th^^ size of the I'eet; 

 the outer falls but little short of tho middle one, while tho tip of the claw of the Inner 

 hardly reaches beyond the third articulation of the middle oiui. Hallux of ordinary 

 relative length. Webs rather narrow; moderately omarginated ; the inner, as nsiiai, 

 the most so. The feet are a lighter tint of the color of the bill, s(uuewhat tending 

 toward vermilion or coral-red, but are not so light as those of liiriiiiilo. 



The wings are very long ; the primaries attenuated, narrow, tapering to their round- 

 ish bnt slender apices. The tertials are short, aiul do not reaoh halfway to the tips of 

 the primaries in the folded wing. Th(^ slial'ts of all are white, with scarcely darker 

 tips. The outer web of the iirst primary is grayish-black, lif;htening into silvery-gray 

 at its tip; its inner web is white, with only a very narrow lino of grayish-dusky along 

 the shaft. This longitudinal dnsky space is very much narrower and lighter than in 

 liiruvdo, so much so, that it is placed as a diagnostic feature by Naumauu in his 

 " Keunz/cichen der Art." The next four or liviN primaries are silvciy-gray, darkest 

 toward their tips; their inner webs mostly white (wholly so at their liascH); but the 

 ■white does not extend so far toward the tips of the feathers as on tlie first primary, 

 and it runs up farther in tho centre of the web than on*the ( dg(( of it. The inner jiri- 

 maries are tho color of the back, broadly tipiied and margined internally with white. 



The tail Is exceedingly long, the exterior feather liinng as much leugtheiu'd, and as 

 narrow, tapering and acute, as in S. piirodixoa. The tail i'eatbers roach beyond the lips 

 of tho folded wings. The under coverts reach to the extremity of the l)ri)ad and 

 rounded central rectrices; the uj)per ones fall short of this length. Tho tail is pure 

 white, the outer web of its exterior feather being grayish-black, lighter basally, and 

 its inner web, and the outer webs of the next two rectrices, having n. considerable wash 

 of pearl-blue. 



The pileum is pure, lustrous greenish-black, so lirond on the checks as to leave only 

 a slender line of white to extend along the edge of the featbors on tho side ol' tho 

 upper mandible. The whole upper parts, as far as the superior caudal reclriiM s, imd 

 including the alar coverts, ])earl-blue, of about tho same shade as in hiriiiido. This 

 color, however, fades into white at the tips of tho tertials and inner secmnlarics. 

 The under parts are but a little ligbli^r shade of the color of the back, this color fading 

 insensibly into whitish on tho chin, throat, and edges of the black pilenm, and ending 

 abruptly at the under tail-coverts, which are jnu'e while, in marked contrast to the 

 rest of the under parts. The inferior alar rectricea and axillary IVatliiiH are also pure 

 ■frhite. 



Winlir plumage of the adult«. — Differs from the above-described summer plumage 

 chiefly in the color of tho fealbers of the head, as usual in the subfamily. The fore- 

 head is white; the crown white, but marked with nanow shaft-lines of black, which 

 increase from before backward until, on the nape, the black is nearly or quite ])nro. 

 A lateral stripe, nfore or less pure and distinct, extcMids forward on the sides of the 

 head over the auriculars, to just, in front of the eyi', leaving, bowivcr, tho (\velid8 

 ■white. Ui>per parts much as in snmmcr, but the under parts from tlio chin to the vent, 



