FAMILY LARIDiE. GULLS AND TERNS. 43 



Outer web of outer tail feather, darker than inner web; back, pearl oniy breast 

 and underparts, pearl gray; bill, in adults, entirely red ; tarsus, usually less than .70 



Sterna paradiscna. Arctic Tern. 



See No. 46. 



Back, bl.ack; a white stripe from forehead, extending over the eye ; l.reast, white; bill, 

 in aQuits, DlacK. c^ ..... „ . .^ 



hterna jnhfjiHosa. Sooty Tern. 



See No. 49. 

 Rack sooty or grayish brown; a white stripe from forehead, not reaching above the 

 eye , b,ll, black. ^5^^,,,^^ anaMHus. Bridled Tern. 



See No. ,50. 

 Back, sooty brown ; underparts, sooty brown. Annus stolidus. Noddy Tern. 



See No. 53. 



* Group 5. Wing, 11 to 13 inches long. 



Bill, black, not tipped with yellow ; feet, blackish ; baclt, pearl gray ; bill, comparatively 

 Short and stout. Gelochelidun nilotica. QuII-billed Tern. 



See No. .39. 

 Bill, black, not tipped with yellow; feet, black; back, black or sooty. 



Sterna fuUginosa. Sooty Tern. 

 See No. 49. 

 Bill, red, tipped with black; feet, orange red ; b.ack, pearl gray or gray and buff. 



Slernri hirundo. Common Tern. Wilson's Tern. 



See No. 4i. 

 Bill, black, tipped with pale yellow ; feet, dark; bill, comparatively long and slender. 



Sterna sandvicensis acnfkivida. Cabot's Tern. 

 See No. .39. 



* Group 6. Wing, 13 to 17 inches long. 



Bill, orange or yellowish; tarsus, less than 1.50; inner web of outer primary, usually 

 with more or less white. Sterna maxima. Royal Tern. 



See No. 41. 

 Bill, red or reddish; tarsus, over 1.50; inner web of outer primary, usually without 

 ^'^'t^- Sterna ixtspia. Caspian Tern. 



See No. 40. 



Bill, black, tipped with yellow. Sterna sandvicensis acujiavida. Cabot's Tern. 



See No. 39. 



* Group 7. Wing, over 17 inches long. 



Bill, red or reddish. Sterna easpia. Caspian Tern. 



See No 40. 



* For directions for measurement, see page 9. 



