389 
Dr. E. Coues on Central-American Laridse. 
5. Thalasseus elegans, 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.) 
</. f6. Thalasseus acufla vidus, 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.—0. S.) 
7. Gelochelidon anglic a, 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 (oneother 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- 
