274 LAKID^. 



Synopsis, p. 327 (1839) ; id. B. Am. 8vo ed. vii. p. 152, pi. 446 



(1844) ; Giraud, B. Long Id. p. 3G0 (1844) ; Gray, List B. Brit. 



3Ius., Anseres, p. 171 (1844) ; id. Gen. B. iii. p. 654 (1846) ; 



Licht. Nomencl. Av. p. 99 (1854) ; Bp. C. B. xlii. p. 771 (1856) ; 



id. Co7isp. Ar. ii. p. 224 (1857) ; Gimdl. J. f. O. 1857, p. 236 

 Cuba); Schl. Mus. P.-Bas, Lari, p. 22 (1863) ; Blasins, J.f. O. 



1865, p. 380 ; Gray, Hnnd-l. B. iii. p. Ill, no. 10949 (1871). 

 " Glaucus occidentalis," Bruch {iiec Audub.), J.f. O. 1853, p. 101, 



taf. ii. fig. 20 (California). 

 Glaucus zonorhynchus, Bricch, J.f. O. 1853, p. 102. 

 Gavina zonorhynchus, Bj). Namn. 1854, p. 212 ; Bruch, J.f. 0. 1855, 



p. 282. 

 Gavina bruchi, Bp. Naum. 1854, p. 212 ; Bruch, J. f O. 1855, 



p. 283. 

 Laroides occidentalis, Bruch {nee Audubon), J.f. O. 1855, p. 282. 

 Larus bruchi, Bp. C. R. xlii. p. 771 (1856). 



Larus zonorhynchus, a. mexicanus, i>^j. Consp. Av. ii. p. 224 (1857). 

 Larus zonorhynchus, b. bruchi, Bp. Consp. Av. ii. p. 224 (1857). 



Adult male in hreeding-plumage. Head, neck, tail, and entire under- 

 parts white ; mantle pearl-grej' (much as in pale examples of L. argen- 

 tatus) ; scapulars faintly tipped with white, and secondaries more 

 broadly so; outermost primary mostlj- black externally, but whitish 

 on the basal portion of the inner web, and with an elongated white 

 subterminal mirror on both webs (though the shaft is black), then a 

 black bar, and the extreme tip white ; 2nd quill with rather more 

 of a white tip, a smaller and rounder mirror barely touching the 

 outer web, and a grey wedge occupying the greater part of the 

 inner web ; 3rd quill without a mirror, more white at the tip and 

 grey on the greater part of both webs ; 4th and oth chiefly grey 

 passing into white, barred with black, and tipped with white ; 6th 

 without a bar in mature birds, or with a very small imperfect one ; 

 upper quills grey with white extremities : bill greenish yellow, 

 with a subterminal black zone and a yellow tip ; gape and orbital 

 ring orange-red to vermilion (in life) ; iris pale yellow ; tarsi and 

 toes greenish yellow. Total length 18-5 inches, culmen 2, wing 14'5 

 to 15, tail 6-25, tarsus 2*2, middle toe with claw 1-8. 

 Adult female similar, but rather smaller. 



Adult in ivinter plumage. Like the above, but streaked with 

 brownish grey on the crown and upper neck. 



Young. Upper parts streaked and mottled with rather pale brown, 

 the feathers of the mantle broadly tipped with huffish white ; second- 

 aries grey basally, with dark centres and whitish borders ; the two 

 outer primaries dark brown; the 3rd, 4th, and 5th similar but tipped 

 with white, and showing grey basally on the inner webs, increasing 

 ascendingly ; in the rest of the quills the grey gradually increases 

 till the dark portion is reduced to an imperfect bar ; tail-coverts 

 white, with brown arrow-headed markings : rectrices white, with 

 a subterminal dark brown bar and whitish tips ; underparts dull 

 white, thickly streaked and mottled with ash-brown on the throat 

 and sides, with smaller and fainter spots on the breast and abdomen : 

 bill yellowish brown basally, blackish terminally ; tarsi and toes 

 brownish. 



