1871.] ON NEOTROPICAL LARIO.E. 577 



Chroicocephalus atricilla, Baird, B. N. A. 850 ; Coues, Ibis, 1864, 

 p. 388; Gundl. Rep. F. N. i. p. 391; Newton, Ibis, 1859, p. 371. 



Xema atricilla, Cab. in Schomb. Guian. iii. p. 761. 



Hab. West Indies, Jamaica (Gosse), St. Croix (Newton), St. Bar- 

 tholomew (Sund.); Cuba (Gundl.) ; Atlantic and Pacific coasts of 

 Guatemala (Salvin) ; Guiana (Schomb .) ; Lower Amazon, near Para 

 (batterer). 



8. Larus serranus. 



Larus serranus, Tsch. Wiegm. Arch. 1844, p. 314; Faun. Per. 

 Aves, p. 307; Burm. Syst. Ueb. iii. p. 449, et La Plata-Reise, ii. 

 p. 519; Scl. et Salv. P. Z. S. 1869, p. 158. 



Larus bonapartii, Scl. et Salv. P. Z. S. 1868, p. 178. 



Chroicocephalus personatus, Brucb, Journ. f. Orn. 1855, p. 289. 



Larus personal us, Schlegel, Mus. des P.-B. Lari, p. 35. 



Gavin personata, Blasius, J. f. Orn. 1865, p. 372. 



Hab. Sierra and Puna regions of Peru (Tsch.) ; Islay and Tinta 

 (Whitely); Bolivia (D'Orb.) ; rep. Argentina, Mendoza (Burm.). 



The first skin of this Gull received from Mr. Whitely was in imma- 

 ture plumage, and was wrongly identified by us with L. bonapartii. It 

 is, however, unquestionably identical with skins of birds in full plumage 

 of the present species subsequently received from the same collector. 



In its adult dress L. serranus is an unmistakable species, from 

 its large size and deep-black head. 



9. Larus franklini. 



Larus franklinii, Swains. F. B. A. ii. p. 424, pi. 71 (1831) ; Sund. 

 Ofv. af K. V. A. F. 1869, p. 590. 



Chroicocephalus franklinii, Bruch, J. f. O. 1853, p. 289 ; Baird, 

 B. N. A. p. 851. 



Larus pipixcan, Wagl. Isis, 1831, p. 515*. 



Chroicocephalus kittlizii, Bruch, J. f. O. 1853, p. 104 (?). 



Larus cinereo-caudatus, Ph. et Landb. Wiegm. Arch. 1861, p. 293. 



Larus cucullatus, Licht. Nomencl. p. 98 (descr. nulla). 



Chroicocephalus cucullatus, Bruch, Journ. f. O. 1853, p. 290; 

 Baird, B. N. A. 851; Coues, Ibis, 1864, p. 388 ; Salvin, Ibis, 1866, 

 p. 198. 



Hab. Lakes of Mexico (Keerl et Boucard) ; Pacific coast of Gua- 

 temala (Salvin) ; St. Bartholomew (Sund.) ; Panama (Suckley) ; 

 coast of Chili, north of Concepcion (Ph. et Landb.). 



After what Blasius has said in his critical remarks upon the 

 Laridce (Journ. f. Orn. 1865, p. 371), there can be little doubt that 

 L. cucullatus is identical with L. franklini. We have ourselves 

 gone carefully into this question, and can arrive at no other conclu- 

 sion, although the American ornithologists appear to be of a different 

 opinion. 



* In the Munich Museum there are six specimens of this Gull, which arc 

 probably Wagler's types, as they are named Larus pipixcan, and are labelled as 

 coming from Mexico. All these specimens are immature, but are of different 

 ages. They belong, no doubt, to L. franklini. — O. S. 



Proc. Zool. Soc— 1871, No. XXXVII. 



