38 



AVIFAUNA OF LATSAN. 



brown at the tip ; outermost pair of rectrices entirely white, brownish at the tips. Iris 

 dark brown, bill and feet black. Total length about 16J inches, wing 10'0, lateral tail- 

 feather G'8, central 3, culmen 16, tarsus 1*8. 

 The plumage of the young, which has never been described before, is spotted like that of 

 other Terns. The head looks white spotted with blackish, all the feathers being blackish 

 with very broad whitish borders. All the feathers of the upper parts are grey, with 

 huffy white borders and deep brown subterminal bands. Tail-feathers with bully white 

 terminal spots, lower parts entirely white. 



The Grey-backed Tern was met with on all the islands, except Midway Island, and was 

 breeding in great numbers on Laysan Island. They lay one single egg only. The laying of 

 one egg is a peculiarity of all the members of the genus Saliplana (or rather Onyclioprion), 

 for also II. anmtheta (Scop.) and H.fuUginosa (Gm.) lay only one egg \ while the members 

 of the genus Sterna lay (so far as is known) two or three eggs. The eggs of Haliplana 

 lunata (Peale) are deposited on the sand, like those of many other Terns. These birds are, 

 compared with the other birds of these islands, very shy, and leave their egg or young 

 before one can approach them. The eggs are in colour quite similar to the well-known eggs 

 of H.fuUginosa (Gm.), but smaller as a rule: those from Laysan measure 18 by 13, 1*8 

 by 1-23, and 1'85 to 13 inches. The Plate gives exact representations of them. 



1 Sec Young, Ibis, 1891, p. 145; Hartert, Ibis, 1S93, p. 310, &c. 



