12 



INDEX TO KEY. 



Section 4. Hind toe, with well-defined 



membraneous lobe or flap ; 



belly, white, sometimes 



tinged on lower part with 



dusky or gray ; head, 



marked with more or less 



white or brownish white ..... 23 



Section 5. Hind toe, with well-defined membraneous lobe or flap ; 



belly, white, sometimes tinged on lower part with 



dusky or gray ; no white or grayish white on head . 24 



Section 6. Hind toe, with well-defined membraneous lobe or flap ; 



belly, not white ; head, marked with more or less 



white or grayish white . . . . . . 25 



Section 7. Hind toe, with well-defined membraneous lobe or flap ; 



belly, not white ; no white on head . . . 26 



Group 5. Birds having wings from 10 to 12 inches long ... 26 



Section 1. Bill, narrow, with tooth-like serrations . 26 



Section 2. Bill, not narrow ; 

 hind toe, without mem- 

 braneous lobe or flap ; 

 belly, white, sometimes 

 faintlytinged with dusky 

 or gray on lower part . ^ 26 



Section 3. Hind toe, without membraneous lobe or flap ; belly, 



not white •.-..... 27 

 Section 4. Hind toe, with well-defined 



membraneous lobe or flap ; 



head, with more or less 



white or grayish white ; 



belly, black . . ^^^^5*^ " 28 



Section 5. Hind toe, with well-deflned membraneous lobe or flap ; 



no white on head ; belly, black ... 29 



