I 



II 



78 



TERNS. 



Ill 



mostly or entirely wliite ; u bluek hjiuco pcncruUy on tho sule of 



tlio lieud inelosiiij; tlie eye tiV. Fdhstku's Tekn (Ini.). 



b*. Outer web of outer luil-feuther ilurker tliun inner web; tun«us 



over "70 70. Common Tkkn (Ini.). 



i*. Outer web of outer tuil-feuther clurker thai» iinier web; tursus 



under •70 VI. Aiu'Tic Tehn (Ini.). 



Ji. Win^' Ijliieki.Hh, over '.»00. 



a. Under parts blucki.sii 75. Sooty Tern Hni.). 



b. Under purtt* white 7<>. Hitini.Ei) Teun (Ini.). 



4. Crown silvery gray ; lores black ; rest of plumage sooty black. 



79. Noddy. 

 II. Wing over 13-00. 



A. Wing 1. ')■(»() or over; outer primary mostly gray. 64. Caspian Tern. 

 Ji. Wing under 15-00; inner half of inner wob of tinst i»riniary wliite. 



65. KoYAi Tern. 



d 



Fia. 01.— First primarfps of adult Terns, seen from below, (n) Caspian Tern; 

 (.6) Royal Tern ; (c) Common Tern ; (d) Arctic Tern ; (e) Roscat« Tern. 



68. Gelochelidon nilotica Hnssdq. GiLL-niLLED Tern; Marsh 

 Tern. Ad. in summer. — Top of tho head and nape black; baclt and wings 

 pale pearl-gray ; outer web of outer primaries silvery ; tip and shaft part of 

 the inner web darker; inner part of the inner web, except for a narrow mar- 



t! • 

 li I 



ll ! 



