LAEUS EBUEXEUS, IVOEY GULL. 649 



DiAO. L. corpore tola alio, rhachidibiis remigum flacis, pedibus nigris, rosiro rlicscciih-JIavo. 

 Hah. — Arctic seas, coming southward in winter. 



AduU, breeding plumage. — Cnlmen straight to the nostrils, then rugnlarly coii\ es ; 

 commis.sare gently cnrved to the tip, where it is considerably deciu ved : ;,)Dys straight 

 to near the angle, which is well defined, the outline from angle to tiii ])ertectly straight. 

 Feathers extending between the rami nearly to the angle. Wiu-- lorg and poiuted, 

 reacLS'jg beyond the t.ail : primaries gradually attenuated to the ti|>. 



Entirely pure white, the shafts of the primaries straw-yellow. Bill dusky greenish, 

 Yellow at ti|j and along the cutting edges. Legs and feet black. 



FouH;'.— Front, chin, and sides of the head, grayish dujky ; the upper jjart of the net ic. 

 all round, irregularly spotted with the same. Seapolars, and upper and under wiiig- 

 oovert<, spotted with brownish-black, the spots most numerous along the lejser overrs. 

 Tips 01 the primaries and tail feathers with a dusky spot. Otherwise as iu the 

 preceding. 



Dimetis.yn-.— Length. 19..50: wing, 13.25 ; bill above. 1,4U : clong gape, 2.10 ; height at 

 nostrils, 0.45 ; tarsus, about 1.45 : middle toe and claw, 1.75. 



The bill of this species, in five specimens before me. varies greatly in size. The dif- 

 ference in shape is also quite notable. But it is in the tarsns that the greatest, variatii.as 

 are found. The shortest tarsus before me measures hut l.-O. This would nearly do for 

 the Lants 6rac?ii;(('i<i(S of HolboU,but the other characters do n.t correspond with tho^e 

 ai ven by that author. This specimen is fioiu ilr. Audubon's collection, and corresponds 

 minutely with his plate. 



The present being a bird of such marked character, there are no quest!ui;» of doubt- 

 ful synonymy which here need special mention. The quotations ■■ albua Scha»ft'er, ITl'y,' 

 and candidus Fabricius, as well as nirens Martens, are all undoubtedly relerable to the 

 inesent species. The other synonyms of the speeies arise chieily from the vaiiun.s gen- 

 era to which the bird has been referred. There is no reasonable doubt that the mi [iposed 

 •■ L. bradq/tarsus" is the same bird ; the description gives no tangible characters. 



Sithgenus Chececocephalus. Eyton. 



^Xemc. BoiE. Isis. 1~\12. .563, nee LrACir. * 



> Gana. Kaup, Sk. Ent. Eur. Thierw. l:;^^. 93 (Z. ridibundus'), nee JIohe. 



> /■ r, •.•luai'tiia. KiCP, op. tit. 99 (i. ichtliiia:ii!^. Pai.i_ V 



> JJildroiolocus. Kaup. op. cit. 99 (i. miiiiitiis, Paix.). 



:=c7i)0«.j(.f(i/(ii'«s. EvT.. Cat. Br. B. l-.iG. -jo (Z. capistratus, Temm.). — Lawi;., B. X. A. 



lS.:r-. >50.— COUES. Pr. Phila. Acad. l-'>2. 309. 

 X Garia, MaCGil.. Man. Orn. ii, 1-42. 239, nee MoHE. 

 yjliiciUa, Bp., 1^54 (A. cattsbai. Bp.). 

 ^M'Jagaria, Bp., lr.;4 (I. franlUni). 



> Cirrhocephahts, Bisuch. J. f. O. lio5, 2^^ (i. cin-hocephaJus, ViEiix.). 

 ^ CUracoceplialui. .Strickl. — Cocxs. 



^ Chroocephalus. Scl. i: salv. 



Ch-AE. Form as in Larus proper, hut general organization less robust (with some 

 exceptions) and the bill usually weaker, slenderer and more acute, and less hooked. 

 Head enveloped in a hood in the breeding season, and white of under parts then usually 

 rosy-tinted. Tail square, or nearly so. 



There are no marked peculiarities in form of this group, the pattern of coloration 

 being mainly its bajis. The species average smaller than those of Larus proper, though 

 the C. iehih:iai'lui is among the largest of the subfamily. The group approximates to 

 Xema and ii'/iotZo ?e(Aia in nearly all respects, but the tail is neither forked nor ccneate. 

 Its subdivision, as indicated iu the above synonymy, is entirely unrequired. 



There are hut three established Xorth American species : the ' '. cucuUaius proving to 

 be the same as C. fraiilUni, while C. minulns is not proven to inhabit this couutiy. 

 These species may be tabulated as follows : 



Anahi>ii of species. 



a. Tarsus longer than the middle toe and claw. 



1. BiU reddish, feet the same ATpaciLL-v. 



ft. Tarsus not longer than the middle toe and claw. 



2. Bill reddish, feet the same filanklixi. 



3. Bill black, feet red or yellow phlladejlp;iia, 



c. Tarsns shorter than the middle toe without claw. 



4. Wings underneath, dark plumbeous Mixrns. 



