668 BULLETIN 50, LTNITED STATES NATIONAL MUSEUM. 



X[ema] sabinei Nelson, Bull. Essex Inst., viii, 1876, 147 (near Chicago, Illinois, 



April, 1873). 

 Chema sabinti Reichenow, Journ. fiir Orn., 1889, 188; Syst. Verz. Vog. Deutschl , . 



1889, 62.— Hartert, Ratal. Vogelsamml. Senckenb., 1891, 243. 

 [Chema] sabinii Heine and Reichenow, Nona. Mus. Hein. Orn., 1890, 360. 

 Zema sabini Holboll, Naturhist. Tidsskr., iv, 1843, 423 (Greenland). 

 Gavia sabinii Macgillivray, Man. Brit. Orn., ii, 1842, 241; Brit. Birds, v, 1852, 



607. 

 Xema collaris (not of Schreibers) Leach, in 8vo ed. Ross's Voy. Baffin Bay, ii, 



1819, 164.— Olphe-Galliard, Contr. Fauna Eur. Occid., fasc. x, 1886, 108. 

 Larus minutus (not of Pallas) Bolsmann, Naumannia, 1852, Bd. ii, Heft iii, 35 



(Westphalia, Germany). 



Genus RHODOSTETHIA Macgillivray. 



Rossia (not of Owen, 1835) Bonaparte, Geog. and Comp. List, 1838. 62. (Type, 



Larus roseus Macgillivray.) 

 Ehodostethia Macgillivray, ^fan. Brit. Orn., ii, 1842, 252. (Type, by original 



designation, Larus rossii Richardson=L. roseus Macgillivray.) 

 Ehodestethia (emendation?') Taczanowski, M6m. Acad. Pt. Petersb., xxxix, 1893, 



1048. 



Very small Laridte (wing 241-261 mm.) with tail cuneate or grad- 

 uated (the middle pair of rectrices much longer than lateral pair), 

 exposed culmen only about two-thirds as long as tarsus, the adults 

 with head, nock, under parts, etc., white (more or less tinted with 

 pink), in summer with a black collar roimd neck. 



Bill relatively yerj small, much shorter than head, the exposed 

 culmen only about two-thirds as long as tarsus, its upper and lower 

 outlines straight and nearly parallel for basal two-thirds, beyond 

 which former is strongh" decurved, the latter decidedly ascending 

 terminally, in a straight line from angle of gonys, the last not promi- 

 nent. Wing long and pointed, the longest primary (outermost) ex- 

 ceeding distal secondaries by about three-fifths the length of the wing. 

 Tail less than (sometimes nearly) half as long as wing, distinctly 

 cimeate or graduated, the middle pair of rectrices longest and much 

 longer than lateral pair; tail coverts very long, extending almost to 

 tip of middle rectrices. Tarsus much longer than middle toe without 

 claw, less than one-eighth as long as wing, rather stout, the some- 

 what roughened bare portion of tibia very short; hallux well-devel- 

 oped, though small, with claw relatively large and strongly curved. 



Coloration. — Adults with back, scapulars, aiKl wings uniform very 

 pale (paUid) neutral gray; rest of plumage immaculate white, usually 

 suffused (often deeply) with pure eosine pink, the neck encircled, in 

 summer, by a narrow black collar. Young with pileum, hindneck, 

 back and scapulars clouded with dusky or sooty blackish, the feathers 

 of lower back, tipped with buffy; tail white, the six middle rectrices 

 tipped with sooty blackish. 



Range. — Circumpolar regions, south in winter, casualU', to Eng- 

 land, Faroe Islands and Helgoland. (Monotypic.) 



