THE BIRDS OF CLIPPERTON AND COCOS ISLAND 505 



The vegetation is extremely rich, though the number of plant 

 species is few. Everywhere a dense green covering of tall trees 

 and smaller undergrowth clothes the irregular mountain slopes 

 and ridges. In this respect Cocos strongly contrasts with any 

 other island of the eastern tropical Pacific. Guadalupe Island, 

 the Rivillagigido and Galapagos archipelagos are for the most 

 part dry and barren, even the wettest parts of the Galapagos 

 being far less humid and less thickly covered with vegetation 

 than is Cocos. 



Animal life on Cocos Island is very scarce. Besides the 

 birds there is present a rat, Mtis nonvegicus^ brought hither 

 by vessels that have touched here for wood and water. A 

 lizard, Anolis townsendi, is rather numerous. With the excep- 

 tion of a snake reported by Townsend this lizard and the birds 

 are the only native land vertebrates known. Hogs have been 

 introduced and now run wild on the island. Insects are very 

 scarce. One cicada occurs but is rare. We obtained one 

 nymph of it in July but saw no adults. A fly, Leiicomelina 

 ^ica^ is somewhat plentiful. There is one ant, Tetramoriutn 

 atiropunctatum, that is extremely numerous, occurring in great 

 numbers on the leaves of all the vegetation. It is minute but 

 its bite is excessively annoying, causing an almost unendurable 

 irritation of the skin. Its presence makes travelling on the 

 island exceedingly disagreeable. We visited Cocos Island 

 June 30 to July 3, 1899. 



SYSTEMATIC ACCOUNT OF THE BIRDS. 



STERNA FULIGINOSA Gmelin. 



Sterna fidiginosa Gmelin, Syst. Nat., i, p. 605, 1788. — Rothschild and 

 Hartert, Novitates Zoologies, vi, p. 191, 1899 (Galapagos). — Saunders, 

 Cat. Birds Brit. Mus., xxv, p. 106, 1896. 



Range. — Intertropical waters and adjacent regions. In the eastern 

 Pacific : Mazatlan, Panama, Rivillagigido Islands, Clipperton Island, 

 Galapagos Islands (Rothschild), Hawaiian Islands. 



Adult Female. — Cat. No. 3826, Stanford University Museum, from 

 Clipperton Island, Nov. 23, 189S. Upper parts sooty black, almost 

 glossy black on nape and top of head. Primaries, except the first, 

 with silvery-gray bloom on upper edge of each barb. Outermost tail 

 feathers long, slender and tapering, reaching 45 mm. beyond second 



Proc. Wash. Acad. Sci., Sept., 1902. 



