478 



THE DIVING BIRDS — rVCfOPODES. 



" V. ringvia," summer dress. 



' III 



" Columbus langvia, Olafk, Rclao n. Isl. ji. 5(i2 " (Riiyant).* 



Colymbustroilc, vur. fi, Donndokfk, Beytr. Zool. II. jit. i. 1794, 875. 



Colijmbus troilc, var. 7, Donn'dorfk, t. c. p. 87(5. 



t Uria lachvynvins, Vai.knc. in tHioris, Voyiiyos Pitt, nutoiir tin Moiulo, Aloout, 1822, 27, pi. 23. 



1 UrUi troilc kucophthalmiis, Kaiiku, Pioilr. Isl. Oiii. 1822, 42; Isis, 1824, 140. 



? Uria Icucopsis, Bukiim, lU'itr. Vof,'i'lk. 111. 1823, p. 880; Isis, 1826, 888. 



IIab. Coasts ami islniuls of the North Atlantic, north to ut lea.st 80°, south, in America, to 

 Southern New Enf,'laii<l in winter ; breeding tVoin Nova Scotia northward. 



Sp. C'haii. Adult, summer iiluvxaije: Head and \wc\i, incliuUng the pikum and naitc, wmionw 

 smoky brown, scarcely — never conspicuously — darker above ; in some specimens ( = 17. " ring- 

 via "), the edge of the eyelids, forming 

 a ring completely round the eye, and 

 a narrow postocular line, white. Up- 

 per i)arts uiiirorm dusky, sometimes 

 nearly black, the secondaries narrowly 

 tipjied with white. Lower parts, in- 

 cluding the jugulum, white, this color 

 anteriorly forming more or less of an 

 angle on the foreneck ; e.xterior leathers 

 of the sides and Hunks broadly edged 

 on both webs with smoky gray ov fuli- 

 ginous-dusky. " Bill black ; inside of 

 mouth gamboge-yellow ; feet black " 

 (Ai'dubon). Wintvr idumutje: Simi- 

 lar to the above, but wh(de throat, 

 cheeks, auricular region, and a broad 

 stripe on each side of the occiput white, 

 the latero-occipital stripe separated from the white below it, except posteriorly, by a narrow stripe 

 of dark smoky brown along the upper edge of the auriculars. Stripes along the sides and Hanks 

 indistinct. Bill and feet dull brownish. Youwj : Similar to the winter plumage, but no white 

 on the sides of the occiput, and that of the foreneck faintly mottled with dusky. Ihnnuj tjouwj .- 

 Head, neck, and upper parts smoky grayish brown, the head and neck liuely streaked with 

 dingy whitish ; lower psirts dingy white 

 centrally. 



Total length, about 17.(M) inches ; 

 extent, 30.00 ; wing, 7,7r)-8.30 (aver- 

 age, 7.99) ; culmen, 1.70-1.90(1.81); 

 gonys, 1.05-1.20 (1. 14) ; depth of bill 

 through angle,. 50-.(>0 ; tarsus, 1.40-l.(iO 

 (1.51) ; middle toe, l.()0-1.75 (1.70).« 



With regard to the perplexing form 

 with white eyelids and postocular streak, 

 we nmst confess ourselves undecided. 

 The theory that it is an individual va- 

 riation of truile seems the "only one 

 which can be adopted, in view of the 

 asserted Tact that the feature in ques- 

 tion is not seasonal or sexual, and that 

 the two forms " are known to copulate 



with each other" (cf. Coues, Pr. Philad. Acad., 1868, 78). There ma, he some mistake, how- 

 ever, as to these supposed facts ; at any rate, were they true, it seems vji/ strange that the siune 

 phase is never assumed by tiie western form of the species (californica). 



> By typographical error printed " Plaff." in original. The correct quotation is probably ColymJius 

 langvigia, Olaffs, Kci.sc, p. 562. 



* Extremes ond average of nine adults. 



U. troile, summer dress. 



