Yg TERNS. 



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



the head inclosing the eye 6'J. Fop.ster's Tern (Im.). 



i2 Outer web of outer tail-feather darker than inner web; tarsus 



HA . 70. Common Tern (Im.)- 

 over '70 ' 



J3 Outer web of outer tail-feather darker than inner web; tarsus 



■1 .HA . . 71. Arctic Tern (Im.). 

 under '70 



B. Wing blackish, over 9-00. 



«. Under parts blackish 75. Sooty Pern m.) 



&. Under parts white 76. Bridled Tern (Im.). 



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

 'C. Wing under 9-00 77. Black Tern (Im.). 



II. Wing over 13-00. 



A Wino- 15-00 or over; outer primary mostly gra:f. 64. Caspian Iern. 

 B Win^ under 15-00 ; inner half of inner web of lirst primary white 



° 65. KoYAL Tern. 





d 



Fig. 61 .-First primaries of adult Terns seeii from below !^^ Ca?Te"rn ^'''' ' 

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



63. GelocheUdon nilotica Hasselq. Gull-billed Tern; Marsh 

 Tern. Ad. in. s«wmm-Top of the head and nape black; back and wings 

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

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



