78 



TKRNS. 



mostly or entirely white ; n black space generally on the side of 



the lii-ail inclosing the eye <''.>. FO-STKU'S TKBN (Im.). 



b*. Outer web of outer tail-feuther darker tlian inner wub; tarsus 



over '70 70. COMMON TERN ( 1m. i. 



6*. Outer web of outer tail-t'euther darker than inner web; tarsus 



under -71' 71. ARCTIC TERN ( \\\\. j. 



. Wing blaekish, over 9 - 00. 



a. Under parts blackish 75. SOOTY TERN (Im.). 



b. Under parts white 76. HKII>LEI> TKKN i Ira.). 



4. Crown silvery gray ; lores black ; rest of plumage sooty . 79. NODDY. 



C. Wing under 9-00 77. BLACK TERN (1m.). 



IL Wing over 13-00. 



A. Wing 15-00 or over; outer primary mostly pray. 64. CASPIAN TERN. 



B. Wing under 15-00; inner half of inner web of first primary white. 



65. KOYAL TERN. 



Fio. 81. First primaries of adult TVrns. seen from below, (n) Caspian Tern ; 

 (6) Royal Tern ; (c) Common Teru ; (d) Arctic Tern ; (e) Roseate Tern. 



63. Gelochelidon nilotica Iln**flq. GULL-BILLED TERN; MARSH 

 TERN. Ail. in summer. Top of the head and nape black ; back and wings 

 pale pearl -jrrny : outer \veh of outer primaries silvery; tip nnd shaft part of 

 tlie inner web darker; inner purt of the inner web, except fr n narrow mur- 



