434 STERNIDJE STERNA 



B. Tail longer, at least half the length of the wing. 

 a. Of large size, wing over 14-0 ; forehead white 

 (in breeding dress) ; a crest of elongate 



feathers on the nape S. hergii, p. 436. 



6. Of intermediate size, wing between 8 and 13 

 inches. 

 a^. A nape crest ; legs black, mantle grey. 



a^. Bill black, yellowish at the tip 8. cantiaca, p. 437. 



b\ Bill yellow S. medm, p. 438. 



6'. No nape crest, legs red to livid, mantle 

 grey. 

 a^. Inner web of primaries edged with white 



to the tips of the feathers 8. dougalU, p. 439. 



b^. Inner web of primaries edged with white, 

 not extending to the tip of the feathers, 

 a^. Outer web of streamers very slightly 



grey 8. vittata, p. 439. 



5'. Outer web of streamers distinctly grey. 



a^. Dark band on the inner web along 



the shaft of the primaries broader, 



occupying about half the web 8. flwviatilis, p. 440. 



h*. Dark band on the inner web along 

 the shaft of the primaries narrower, 

 occupying only about a quarter the 



width of the web 8. macrura, p. 442. 



c'. No nape crest, legs blackish,^ mantle sooty 



black 8. fulAginosa, p. 444. 



c. Of small size ; wing less than 8'0. 



a}. Forehead black to the base of the bill ; bill 



black 8. halcena/ruin,TpAA'2. 



¥. Forehead white. 

 a^. Only the two outer primaries darker than 



the inner ones 8. mvnuta, p. 443. 



b^. The three outer primaries darker and con- 

 trasting with the inner one 8. saundersi, p. 444, 



759. Sterna caspia. Caspian Tern. 



Sterna caspia. Pall., Nov. Comm. Petrop. xiv, i. p. 582, pi. 22, fig. 2 

 (1770) ; Kirh, Ibis, 1864, p. 337 ; Layard, B. 8. Afr. p. 369 (1867) ; 

 Finsch Sf Hartlaiib, Vog. Ost-Afr. p. 826 (1870) ; Ourney, in Ander- 

 sson's B. Damaral. p. 359 (1872) ; Dresser, B. Eur. viii, p. 289, pi. 

 584 (1877) ; Sharpe,. ed. Layard's B. 8. Afr. p. 703 (1884) ; Flech, 

 Journ. Ornith. 1894, p. 379; 8helley, B. Afr. i. p. 163 (1896); 

 Beichenoiv, Vog. Afr. i. p. 56 (1900). 



Hydroprogne caspia, 8aimders, Cat. B. M. xxv, p. 32 (1896). 



