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GENUS GELOCHELIDON. Outer tail feathers longest, pointed; tarsus 

 very long ; bill robust, obtuse ; tail less than half length of wing. 



643. G. anglica, Mont. (G. macrotarsa, Old.; Sterna anglica), Gull- 



billed Tern (Long-legged Tern). 



Summer Plumage. Head and back of neck black. 



Winter Plumage. Head and back of neck white. 



Total length, 15 in. ; culmen, 1'8 to 2 in. ; wing, 12 to 13 in. ; 

 tail, 5'5 in. ; depth of fork, 1 '5 in. ; middle toe and claw, T25 in. 

 Hab. : 2, 3, 4, 6. 



GENUS HYDROPROGNE. Outer tail feathers longest ; tarsus short ; 

 tail very short, less than one-third length of wing ; bill exceptionally 

 stout and deep. 



644. H. Caspia, Pall. (Sylochelidon strenuus, Gld. ; Sterna caspia), 



Caspian Tern. 



Summer Plumage. Head and back of neck black ; forehead, 

 crown, and nape glossy greenish-black ; grey above, white beneath ; 

 bill vermilion- red. 



Winter Plumage. Head and back of neck white ; crown streaked 

 with white. 



Young. Back and tail mottled. 



Total length, 20 in. ; culmen, 3 '3 in. ; wing, 16'5 in. ; tail, 6 in. ; 

 depth of fork, 1'25 in. ; tarsus, 1'6 in.; middle toe and claw, 1*7 in. 

 (Individuals vary in size. ) 

 Hab. : 1, 2, 3, 4, 5. 



GENUS STERNA. Outer tail feathers longest, pointed ; tarsus short ; 

 tail at least half length of wing ; bill compressed and slender ; tarsus 

 never exceeds the middle toe with claw. 



645. S. doilgalli, Mont. (S. nigrifrons, Masters; S. gracilis, Gld.), 



Roseate Tern (Graceful Tern). 



Roseate tinge on white breast ; inner webs of primaries white to 

 the tips ; upper parts very pale grey ; crown black in breeding 

 plumage ; forehead black to base of culmen. 



Total length, 15 '5 in.; wing, 9 '25 in. 



Hab. : 2, 3, 9. 



646. S. media, Hors. (Thalasseus torresi, Gld.), Lesser Crested Tern 



(Indian Tern). 



Kump and tail grey, like the back ; bill orange-yellow to red ; 

 crown black in breeding plumage, and forehead black to base of 

 culmen. 



Total length, 17 in. ; wing, 12 in. 

 Hab. : 1, 2, 3, 4. 



647. S bergii, Licht. (Thalasseus pelecanoides, King ; T. poliocercus, 



Gld. ; T. cristatus, Blyth), Crested Tern (Bass Straits Tern). 



Crown black in breeding plumage ; front of forehead white ; lores 

 white ; bill greenish-yellow ; nape feathers long ; rump dark grey, 

 like the mantle. 



Total length, 20 in. ; wing, 14 in. 

 Hab. : 1, 2, 3, 4, 5, 6, 9. 



648. S. ironfalls. Gray (S. melanorhyncha, Gld. ), White-fronted Tern 



(Southern Tern). 



Crown black in breeding plumage ; front of forehead white ; lores 

 white ; bill black. 



Total length, 16 to 17 in. ; wing, 11 '25 in. 



Hab. : 1, 2, 3, 4, 5, 8. 



