G12 STERCORARIUS PARASITICUS, PARASITIC JAEGER. 



Stercorarins narasiticns, Sch^ff., Mus. Orn. 1779, 62, pi. 37 (/«sc?(s).— Selys-L., Fn. Belw. 



1842, 155.— Gray, Gen. of B. iii, 1849, 653 ; List Br. B. 1863, 228.— Lawr., B. 



N. A. 1858, 839: Anu. Lye. N. Y. viii, 1866, 299.— Coues, Pr. Pbila. Acad. 1861, 



243 ; ma. 1863, 132 ; Pr.^Ess. lust, v, 1868, 305 ; Key, 1872, 309 ; Elliot's Prybi- 



lov Is. 1874.— Malm., J. f. 0. 1865, 205.— Newt., Ibis, 1665, 570.— Schl., Mus. 



P.-B. iv, 1«63, 47.— Dall «& Bann., Tr. Cbic. Acad, i, 1869, 303.— Tuknb., B. E. 



Pa. 1869, 47. 

 Catharacia coprotheres, Brunn., Orn. Bor. 1764, 38. 

 Le^tris coprotheres, Des Murs, Tr. Ool. 1860, 551. 

 Catarractes parasita, Pall., Zoog. R.-A. ii, 1811, 310. 

 Lestris parasHa, Keys. & Blas., Wirb. Eur. 1840, 95.— Bp., Cat. Met. Ucc. 1842, 80; Rev. 



Crit. 1850, 202.— Schl., Rev. Crit. 1844, 85.— Midd., Sib. Reise, ii, 1853, 241. 

 Cataracfa cepplms, Leach., Syst. Cat. 1816, 39. 

 Stercorarins cepplms, Steph., Gen. Zool. xiii, 1826, 211, pi. 23.— Sw. & Rich., F. B. A. ii, 



1831, 432.— Degl., Orn. Eur. ii, 1849, 295. (Not of authors.) 

 Stercorarins crepidatus, Vieill., Nouv. Diet. d'Hist. Nat. 1819, 155. (Nee Gm., Lath. ?) 

 Lestris crejmlafa, Temm., Man. 1815, 515.— Degl., Mem. Soc. Roy. Lille, 1838, 108.— 



SCHiNZ, Eur. Fn. 1840. 390. (Juv.). 

 Lestris richarclsoni, Sw. & Rich., F. B. A. ii, 1831, 433, pi. 73.— Nutt., Man. ii, 1834, 319.— 



Bp., List, 1838, 63.— Eyt., Cat. Br. B. 1836, .51.— Aud., Orn. Biog. iii, 1835, 503 ; 



Syu. 1839, 332 ; B. Am. vii, 1844, 190, pi. 452.— Temm., Man. iv, 1840, 499.— 



ScHiNZ, Eur. Fn. i, 1840, 392.— GiR., B. L. I. 1844, 367.— Thomps., Nat. Hist. 



Ireland, iii, 1851, 394. 

 Cataractes richardsonii, Macgil., Man. ii, 1842, 257. 



Stercorarins richardsoni, Covks, Rev. Lestrid. Pr. Pbila. Acad. 1863, 135. 

 Lestris boji, schleepii, benickii, Brehm, V. D. 719, 720, 723. 

 (?) Lestris hardyi, spinicauda, Bp., Consp. ii, 1856, 210. (Blasitis puts these under huffoni.) 



Diag. St, rectridbus viediis rigidis, acuminatis, ultra cceteras ^-pollices porr-ectis ; tarsis sub- 



asperis. 



Eab. — North Atlantic Ocean, and sea-coasts of Europe and America. Interior of 

 Arctic America. 



Adult, breeding plnma fie (No. 16802, Mus. Smithson.). — Bill much shorter than the head 

 or tarsus; as high as broad at the base; basally rounded, compressed from nostrils to 

 tip ; rather robust, the sides converging from base to apes. Culmeu broad, flattened, 

 scarcely appreciably convex to the unguis, which rises slightly above the level of the 

 cere, is moderately convex, tip uot very strongly deflexed. Rami very long; gonjs 

 very short ; both somewhat concave in outline. Eminentia symi)hysis small but well 

 marked. Tomia of superior mandible at first ascending and a little concave; then 

 descending and a lit'le convex ; again, very decidedly concave as it decurves toward 

 the tip. Cere without oblique striaj ; with a straight longitudinal sulcus on each side 

 of the culmen. Feathers extending far forward on superior mandible, with a curved 

 free outline, so broad that the feathers of the sides meet over the culmen. Feathers on 

 inferior mandible also project considerably, almost filling the triangular sulcus on the 

 side as well as the angular space between the rami. Middle of eye just over angle of 

 mouth. Wings moderately long, stroug, pointed ; first primary much the longest ; rest 

 regularly and rapidly graduated ; all rather narrow and tapering to an acute apex, 

 soiuewhat rigid and falcate. Secondaries short and inconspicuous ; broad, the tips of 

 the outer ones nearly square, of the inner obliquely incised, the apex being formed by 

 the inner web alone. Tertials long, soft, flexible. Tail moderately long, contained 

 not quite two and a half times in the wing; very slightly rounded, the graduation 

 being only half an inch. Feathers moderately broad quite to their tips, which are 

 truncated. The central pair project three to four inches. They begin to taper about 

 four inches from their apices, and regularly converge to a very acute tip. Upper tail 

 coverts moderately long ; the inferior still longer, but neither as long as in sliia. Feet 

 rather short and quite slender ; tarsi as long as the middle toe and claw. Tibia naked 

 half an inch above the joint. The tcutellation aud reticulation is the same as that 

 already described, but the nails are weaker and less arched, though fully as acute. A 

 decided occipital crest and a calotte. Nuchal region with the feathers acuminate and 

 rigid, with loosened fibrilhe. Pileum, occipital crest, aud whole upper j)arts deep 

 brownish-black, with a somewhat slaty tinge, and a slight but appreciable metallic 

 shade ; this color deepening iuto quite black on the wings and tail. Rhachides of 

 primaries and rectrices whitish, except at thoir tips ; the inner vanes albescent baso- 

 iuterually. Chin, throat, sides of head, neck all round, and under parts to the vent, 

 pure white ; the feathers of the latero-nuchal region rigid, acuminate, with discon- 

 nected tibrillaj, light yellow. Under tail coverts like the upper parts, but somewhat 

 of a fuliginous tint ; the line of demarcation from the white of the abdomen very 

 trenchant. 



Nearly mature (No. 20144). — Size aud form of the adult. Pileum and latero-nuchal 



