420 LAEID^. 



Larus cucullatus (Licht. MSS.), Eeichenb. Natat. t. 23. fig, 296" ; Salv. Ibis, 1865, p. 188". 

 Chroicocephalus cucullatus, Licht. Nomencl. Av. Mus. Berol. p. 98 " ; Coues, Ibis^ 1864, p. 388 " ; 



Salv. Ibis, 1866, p. 198 ". 

 Chroicocephalus atricilla (nee Linn.), Sclater, P. Z. S. 1864, p. 179". 



Ptil. cestiv. Supra cinerascenti-schistacens ; collo postico et lateral] et corpore subtus pure albis, hoc rosso 

 induto ; pileo undique ni^errimo ; fascia supra- et infraoculari albo ; nropjgio et sapracandalibos 

 lateralibus albis ; supracaudalibus reliquis et rectricibus cinereis, lateralibus fere albis ; alia cinereis 

 dorso concoloribus, primariis intimis et secundariis albo terminatis, primariis extemis albo terminatis, 

 subtenninaliter nigro fasciatis, primarii primi pogonio externo nigro : rostro corallino ; palpebris coral- 

 linis; pedibus sordide rubris ; iride sordide grisescenti-brunnea. Loog. tota circa 135, alae 11-5, 

 candle 4-2, culm. 1-35, tarsi 1'6. 



5 baud a maii distingnendus. Long, tota circa 13-9, alae 10'7. (Descr. maris et feminae ex Champerico. 

 Mus. nostr.) 



Plil. Jiiem. ptilosi aestivae similis, sed pUeo albo, nigro notato. 



Juv. Sordide cineraceus, alls brunnescentibus, torque coUari albo indistincto, einereo adnmbrato ; fronte et 

 facie lateral! albis, pileo reliquo albicante nigro marmorato, plumis nigris, albido margioatis ; cauda 

 pallide cinerea, terminaliter late brunneo fasciata. (Descr. femioee jnnioris ex Chiapam. Mus. 

 nostr.) 



Hal. Intebiok of Xoeth America, chiefly west of the Mississippi River and east of the 

 Eocky Mountains, breeding from Iowa northward ■\ — Mexico i" ^^ ( Wagler ^), west 

 coast 6, lakes of Mexico {Keerl & Bmtcard 2), city of Mexico {White « ^■'), 

 Zacatecas [Richardson ^), Mazatlan {Grayson ^ ^), Laguna de San Baltazar, Paebla 

 {Ferrari-Perez *), Progreso, Yucatan {mus. nostr. ^) ; Guatejiala, Pacific coast ^ ^^, 

 Chiapam « ^'^, Champerico « " {0. S.) ; Paxaiia {SucJcley ^). — West Coast op 

 South Amekica to Chile « ,- West Indies, St. Bartholomew «. 



The present species, like the preceding, belongs to the hooded section of the genus 

 Larus and has a black head in summer. It differs from L. Philadelphia in its dark 

 slaty-grey mantle, and has the outer quills grey above, with a broad white tip and a 

 broad black subterminal bar. 



i. ^rfflwMzW breeds in marshes and is found in the interior of North America in 

 summer, occurring in Central America only in the winter months. Grayson procured 

 a few specimens at Mazatlan in December, but it was not common and was only 

 observed during that month ^ 8. It is scarcely known on the eastern coasts of Mexico 

 and appears to migrate through the interior, being found on the lakes and in the 

 Valley of Mexico in winter ; it has, however, been met with at Progreso in Northern 

 Yucatan *. 



Salvin noticed the species on the Pacific coast of Guatemala, where it was generally a 

 short way out at sea i*, and he procured specimens at Champerico ^^ and on the lagoon 

 of Chiapam ^^. It ranges along the west coast of South America as far as Concepcion 

 in ChUe «. 



The nest is placed upon the water among the bulrushes, of which it is composed ^. 

 The eggs in our collection vary in form from pointed to a blunt oval ; the ground-colour 

 is olive-buff, spotted and blotched with dark and light brown, and underlying pale 



