15. LARCS. 227 



Larus frobeenii, Phil, et Landb. Wiegm. Arch. 1861, p. 292 ; iid. An. 

 Univ. Chile, xxxi. p. 288. 



Adult in hreeding-plumacje. Head, upper neck, and under surface 

 white, with a very faint tinge of grey round the lower neck and a 

 deeper grey tint at the junction with the mantle which is sooty 

 black ; wings rather browner black ; scapulars and secondaries 

 broadly tipped with white, the latter making a very conspicuous alar 

 bar ; primaries sooty black, the five upper ones tipped with greyish 

 white ; upper tail-coverts white ; rectrices chiefly black, but tipped 

 with white, irregularly marked with white on their basal portions 

 (concealed by the coverts), and white along the entire outer web of 

 the outermost pair ; under wing-coverts grey : bill stout, chiefly 

 yellow, but red in front of the angle and often with a blackish mark 

 or zone ; iris brown ; tarsi and toes rather coarse, yellow, with 

 brighter webs and soles. Total length 20 inches, culmen 2-3, wing 

 14-5, tail 6-3, tarsus 2-4, middle toe with claw 2-25. 



The male is probably a trifle more robust than the female. 



Immature. Like the above, except that the head and neck are 

 thicklj' covered with dark brown streaks which become confluent on 

 the hind neck and form a fairly-defined hood ; some dark brown 

 markings on the upper wing-coverts ; dark zone on the bill more 

 strongly marked. 



Youncf. Darker than the above on the head and neck ; the 

 upper surface chiefly greyish brown, but the feathers have pale tips, 

 which give a mottled appearance ; tail-coverts with brownish central 

 streaks ; rectrices with less white ; under tail-coverts white ; abdo- 

 men and breast brown, much as the mantle : bill with more black, 

 and paler yellow at the base. 



Hab. Coasts of Chile and of Peru, up to Callao, 12° S. lat. 



a. Imm. sk. Coquimbo, Chile, Nov. (Ad- H. Saunders Coll. 



iniral A. H. Markham). 

 h. Juv. sk. Iquique, Pniv. Tarapaca {S. F. H. Saunders Coll. 



Rowland). 



c. Juv. sk. Mollendo, Peru, Sept. {Commr. II. Saunders Coll. 



MacFarlane). 



d, e. 5 ad. et Islay, Peru (JT. Whitely). Purchased, 

 juv. St. 



f. $ imm. sk. Islav, Peru, Mav (ff. If'.). Salviu-Godman Coll. 



V. Juv. sk. Islay, Peru {H.' W.). Tweeddale Coll. 



h. Ad. sk. San Lorenzo I., Callao Bay H. Saunders Coll. 



{Admiral Markhayn). 



i. Juv. sk. Callao Bay, Aug. {Admiral 11. Saunders Coll. 



Markham). 



k. Imm. .sk. CnWao Bay {li. Jump). H. Sauuders Coll. 



20. Larus crassirostris. 



Larus crassirostris, Vicill. N. Diet. crHist. Nat. xxi. p. 508 (1818, 

 e.r Kruse?istern) (Nagasaki, Japan) ; id. Enc. Meth. i. p. 340 

 (1820) ; Gray, Geti. B. iii. p. 054 (1846) ; Swinh. Ibis, 1803, p. 428 

 (Formosa) ; 'id. P. Z. S. 1863, p. 326 (China) ; Schlo/. Mus. P.-Bas, 

 Lari, p. 8 (1863) ; Gray, Hand-l. B. iii. p. 113, no.' 10177 (1871) ; 

 Swinh. P. Z. .S. 1871, p. 421 ; id. Ihis, 1874, p. 104 (Hakodadi) ; 



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