606 BUPHAGUS SKUA, THE SKUA. 



isli ; tlieir rhacliifles white, except toward the apices ; tbe remiges and rectrices white 

 for some distance from the bases. This white on the tail is concealed by the long tail- 

 coverts, bnt appears on the outer primaries as a conspicuous spot. The bill and claws 

 are blackish horn ; the feet pure black. Bill, from base to tip, 2.10; to end of cere, 

 1.20 ; gape, 3.00 ; height at base, 0.75; width a little less; rami, 1.60 ; gonys, 0.50; wing, 

 16.00 ; tail, 6.00 ; tarsus, 2.70 ; middle toe and claw, 3.10. 



YoiDuj-of-tlie-year (Spec. No. 22266, Mus. S. I. from Iceland, shot September 1, 1839). — 

 The size is much less than that of the adults; the bill every way weaker and .slen- 

 derer ; the cere illy developed ; strije are not yet apparent, and its ridges and aiigles all 

 want sharpness of detinition ; the gonys is extremely short. Wings exceedingly short 

 and rounded, the quills having very different proportional length from those of the 

 adults ; the second being longest, the third next and but little shorter ; the hrst about 

 equal to the fourth. The inner or longest secondaries reach, when the wing is folded, 

 to within an inch or so of the tip of the longest primary. The central retrices are, if 

 anything, a little shorter than the next. The colors generally are as in the adult, but 

 everywhere duller and more blended, having few or no white spots ; and though the 

 reddish spots are numerous and occupy a large space on each feather, yet in color they 

 are very dark and dull. These dull reddish spots are especially numerous along the 

 edge of the forearm and on the least and lesser coverts. On the under parts the colors 

 are lighter, duller, and still more blended than above. The prevailing tint is a light, 

 dull rufous, most marked on the abdomen ; but there and elsewhere more or less ob- 

 scured with an ashy or plumbeous hue. The primaries, secondaries, and tertials, 

 together with the rectrices, are dull brownish-black; their shafts yellowish-white, 

 darker terminally. At the bases of the primaries there exists the ordinary large white 

 space, but it is more restricted than in the adults, and so much hidden by the bastard 

 quills that it is hardly apparent on the outside of the wing, though very conspicuous 

 on the inferior surface. The legs and feet are parti-colored — brownish-black, varie- 

 gated with yellowish. Bill, along culmen, 1.75; along gape, 2.75; height at base, 0.50 ; 

 length of gonys, 0.35 ; tarsus, 2.60 : middle toe and claw the same. Wing, from the 

 flexure, 12.25. Tail, 5.75. 



This species requires comparison with no other of North America. B. anfarcUcus, 

 from the sea-coasts of the Southern Hemisphere, differs somev.hat in the shape of the 

 bill. This is shorter, deeper, and more obtuse at the tip. 



Although this species is burthened with an extensive synonymy, yet in consequence 

 of its marked character the list is pretty definite. It is one of the very oldest species, 

 being well known to pre-Linuean writers. It is well described by both Brisson and 

 Briinnich, the foruier considering it as a Gull, the latter making it the type of his 

 genus Catharaeta. The Lams Jieeask of Latham is stated to be 22 inches, with a bill of 

 3 inches, and its habitat is given as " Hudson's Bay." There is no one of the Lestridinoc 

 inhabiting North America but the present which is of such large dimensions. The 

 plate which Vieillot (Galerie des Oiseaux) gives of his Stercorarius pomarinus shows con- 

 spicuously the large white alar spot, which is diagnostic of the present species. Vieill- 

 lot had previously recognized the characters of the species with precision. 



Subgenus Stercorarius, BHss. 



= Stei'corariits, Briss., Orn. v, 1760, 149. (Type Lams lyaraaiiicus, Linn.). — CouES, Pr. 



Phila. Acad. 1863, 128 ; and of many authors. 

 'C.Catlxaracia, BrxJnx.. Orn. Bor. 1764, 32. 



<^Lams, p. Lixx., Syst. Nat. 1766. Also of Gm., Lath., Meyer, 

 =:Lestris, III., Prod. 1811, 272. (Type L. parasiticus, Linn.). And of most authors. 

 =:Pra'datrix, Vieill., Anal. 1816, 62. 

 =Labbus, Raf., 1816. 

 > Coprotheres, Reich., 1850. 



Gex. Char. — Bill equal to middle toe without the claw, moderately robust, the height 

 at base more than a third the length of the culmen ; stri;e and sulci few and slightly 

 marked. Encroachment of feathers on bill very great, especially on the upper mandi- 

 ble, where it greatly exceeds that on the lower, and is of a different outline from that 

 of Buphagits. Occiput decidedly subcrested. Wings exceedingly long, the primaries 

 narrow, tapering, with quite acute tips. Tail long; the lateral feathers more or less 

 graduated ; the central pair considerably, sometimes excessively, elongated, tapering, 

 and acuminate. Feet rather slender, the tarsi equal to or slightly longer than the 

 middle toe and claw. Size moderate or small. Form less robnsr, general organization 

 much less powerful than in Buphagus. Nearly bicolor when adult ; passing through vari- 

 ous states of plumage before arriving at maturity. 



The preceding paragraph expresses the chief diagnostic features of this subgenus. 

 A comparison ■s^'ith Bupliagus has already been instituted, and an analytical table of 

 its species given on a preceding page. It only remains to notice its bibliographj'. 



