BIRDS OF NORTH AND MIDDLE AMERICA. 645 



C[hro(cocrpJmln>t] cucuUafus Suckley. in Cooper and Suckley, Re]). Pacific R. R.. 



Surv., xii, pt. ii, ISfiO, 277, i.i text (Panama). 

 [Gavia] cucullata Bonaparte, Compt. Rend., xlii, 185G, 771. 

 [Chroicocephalus] HftUtzii Bruch, Journ. I'iir Orn., 1853, 104 (a. Ohili; based on 



a drawing). 

 [Gavia] kiulitzii Bonaparte, Compt. Rend., xlii, 1856, 771. 

 [Chroicocephalus] schimperi Bruch, .lourn. fiir Orn., 1853, 10-1 ("New Zealand"). 

 [?] [Chroicocephalus] serranus (not Larus serranus Tschudi) Bruch, Journ. fiir 



Orn., 1853, 106 (Peru). 

 Larus cinereo-caudatus Philippi and Landbeck, Wiegmaun's Arcliiv fiir Naturg., 



1801. i, 293. 



CHROICOCEPHALUS PHILADELPHIA (Ord). 



BONAPARTE'S GULL. 



Adults in summer (sexes alike). — Head and upper part of neck 

 dark gra}^ (between dark and dusky purplish gray); an elongated 

 white spot on each eyelid; lower neck (all round), entire under parts^ 

 including axillars and under wing-coverts, lateral and lower portions 

 of rump, upper tail-coverts, tail, edge of wing, alula, primary coverts 

 and greater portion of distal primaries immaculate white, the neck 

 and under parts often suffused with delicate eosine pink (especially 

 in life and more recently killed specimens); back, scapulars, greater 

 part of wings (except distal primaries) and upper and median por- 

 tio]is of rump, uniform delicate pale neutral gray; outer web of outer- 

 most primary and terminal portion of lirst, second and tliird (count- 

 ing from outside) black; fourth priinary similar to third but inner 

 web pale neutral gray; fifth and sixth primaries pale neutral gray 

 with a large subterminal space of black and tipped with white (the 

 third and fourth also with a small apical spot of white) ; remaining 

 (proximal) primaries pale neutral gray, without white tips but with 

 a subterminal spot (usually, or mostly, on inner web only) of black; 

 "bill black; interior of mouth, together with legs and feet, clear, rich 

 orange-red or orange-vermilion; iris dark brown; naked orbital ring 

 black. 



Adults in winter. — Similar to summer adults, but head and whole 

 neck white, the occiput tinged with gray and the auricular region 

 with a spot of dusky grayish; logs and feet paler red or flesh color. 



Young. — Lateral and imder portions of head and neck, entire 

 under parts, upper tail-coverts, and basal three-fourths (approxi- 

 matcl}') of tail immaculate white; a dusky spot on auricular region; 

 crown, occiput, and upper back grayish brown; scapulars and pos- 

 terior interscapulars (lower back) grayish brown tipped with pale 

 buff; central area of lesser wing-covert region dusky grayish brown; 

 rest of wing-coverts, edges of secondaries, greater portion of proximal 

 primaries, and upper and median portions of rmnp light neutral 

 gray; distal portion of tail (forming a well-defined broad band) black 



