Dr. E. Coues on Central- American Laridse. 389 



5. Thalasseus eleganSj Gambel. 



The single specimen is absolutely identical with a typical 

 T. elegans from California; but, being an immature or winter 

 example, it entirely wants the rosy hue of the under parts of 

 full-plumaged birds. It is the first specimen I have seen in 

 this condition. 



a. San Salvador, December 1862. (Shot by Capt. Dow. — O.S.) 



6. Thalasseus acuflavidus, Cabot. 



The eight specimens are somewhat smaller than the average of 

 North American examples, agreeing in this respect with nume- 

 rous individuals from the Antilles. All are undoubtedly speci- 

 fically identical. 



a, b. Immature birds, Chiapam, Guatemala, January 1863 ; 

 (and other specimens. — O. S.) 



7. Gelochelidon anglica, Bp., ex Montag. 



Quite identical with numerous North American and Eu- 

 ropean specimens. The single specimen is in full winter 

 plumage. The pileus is only represented by numerous deli- 

 cate, sharply defined shaft-lines of black, which, on the auri- 

 culars, blend into a dusky spot. The forehead is pure white. 

 There is a sharply defined anteocular black lunula. 



a. Male, adult, winter plumage, Chiapam, February 1863; 

 and other specimens. 



8. Sterna paradisea, Briinn. 



A" fine adult example, smaller than the average of North 

 American specimens, but otherwise quite similar. 



a. Male, "Grassy Cay,^^ May 20, 1862 (one other specimen. 

 —0. S.). 



9. Sterna ? 



A very young example, which I find it impossible to label 

 with certainty. It is almost exactly like S. paradisea ; but the 

 upper parts are rather too dark, and the primaries want the 

 most essentially diagnostic character of those of S. paradisea 

 {vide my " Review of the Terns of North America," in Proc. 

 A. N. S. Philadelphia, December 1862, p. 551). At the same 

 time, the colours of the bill, and some other peculiarities, pre- 

 clude its definite reference to S. hirundo, which it otherwise re- 



