408 LAEID^. 



latter part of March, when it congregated on the beach in large numbers, and in a 

 short time disappeared for its breeding-grounds^. Mr. Nelson did not find the 

 species on the Tres Marias Islands ^. In winter it extends its range along the western 

 coast of South America to Peru and Chile ^. 



An egg taken by Captain Stone at Guaymas was white with a pinkish tinge ; the 

 markings were quite bold and distinct, and were of a deep black and burnt-sienna 

 colour, with subdued shell-markings of lavender-grey ^■ 



7. Sterna auaestheta. 



L'Hirondelle de Mer de I'Isle de Panay, Sonn. Yoj. Xouv. Guin. p. 125, pi. 84 '. 



Sterna aruestheta, Scop. Del. Faun, et Flor. Insubr. ii. p. 92 ^ ; Baird, Brewer, & Ridgway, Hist. 



X. Amer. Birds, ii. p. 316 ' ; Zeledon, Cat. Aves Costa Rica, 1887, p. 133 * ; A. O. U. Check-]. 



N. Amer. Birds, 2nd ed. p. 2Q' ; Saunders, Cat. Birds Brit. ^Mus. xxv. p. 101 ° ; Gates, Cat. 



Eggs Brit. Mus. i. p. 190 \ 

 Haliplana panaya (Lath.), Salv. Ibis, 1864, p. 381 " ; Coues, Ibis, 1864, p. 391 '. 

 Haliplana panayensis (Gm.), Salv. Ibis, 1866, p. 199 ". 

 Onychoprion panayensis, Scl. & Salv. P. Z. S. 1871, p. 572 " ; Zeledon, Cat. Aves Costa Rica, 18S2, 



p. 36 ". 

 Haliplana discolor, Coues, Ibis, 1864, p. 392, note ^'. 



Plil. cegtiv. Supra fuliginoso-bruimea, schistaceo lavata ; interscapulio canescentiore ; pileo nnchaqne niger- 

 rimis ; fronte angusta et supercilio brevi pure albis ; loris et fascia lata oculari nigris, pileum nigrum, 

 lateralem conjungentibus ; coUo postioo celato, faciei et colli lateribns et corpore subtos toto pure albis ; 

 alis dorso concoloribus ; tectricibus primariorum et primariis nigricantibns, vix cinereo lavatis, et intus 

 cuneatim albis ; uropygio et canda clarius sohistaceis, rectricibns intus et basin versus albis, externis 

 plerumque albis apieem versus cinerascentibus, rectrice extima alba, vix subterminaliter cinerascente : 

 rostro et pedibus nigris ; iride saturate brunnea. Long, tota circa 15-0, alae lO'l, candae 2-S, rectrice 

 extima 6'5, culm. 1-55, tarsi 0"8.5. (Descr. maris adulti ex Lighthouse Reef. ilus. nostr.) 



2 mari similis. Long, tota circa 14-8, alee 10-45. (Descr. feminse adults ex Southern Water Cay. Mus. 

 nostr.) 



JPtil. hiem. ptilosi asstivae similis, sed pileo albo maculate distinguenda. 



Jiw. adultis hiemalibus similis, sed pUeo toto nuchaque nigro striatis, notaei plumis albido marginatis ; 

 tectricibus alarum minimis nigricantibus ; primariis et rectricibus saturatioribus, intus magis restricte 

 albidioribus : subtus pure alba. (Descr. av. juv. ex Florida, ilus. nostr.) 



Rab. North America, casual in Florida ^. — British Honduras, Cays of Belize coast ^^, 

 Lighthouse Keef^, Saddle Cay^s, Curlew Cay^ Southern Water Cay^ (0. ,S'.) ; 

 Costa Rica (Zeledon * ^^). — West Indies ^. — Coasts and Isla>'ds of South Atlantic ^, 

 Indian, and Pacific Oceans ^. 



Owing to their style of coloration, the Sooty Terns have been often considered to 

 be generically distinct from the typical species of the genus Sterna, but IMr. Howard 

 Saunders (t. c. p. 110) has been unable to find any structural characters to warrant 

 their separation. 



The present species is easily recognized by its dark smoky-brown upper plumage and 

 white breast, this latter character being present in the young birds also. It occurs 

 occasionally in Florida, but breeds in Central America, as Salvin procured the eggs on 



