■194 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



dd. Wing less tlian 90.17; calmen less than 26.42. 

 e. Depth of bill at base more than 20.32; width of man(li])le at base more 



than 16.51. (Tower Island. ) Geospiza pachyrhyncha (p. 498) 



ee. Depth of bill at base less than 20.32; width of mandible at base less than 

 16.51. (Charles, James, Bindloe, Abingdon, Indefatigable, Jei-vis, 

 Albemarle, Duncan, Barrington, and Wenman islands.) 



Geospiza strenua (p. 496) 

 cc. Bill longer and narrower (depth at base not decidedly, if any, greater than 

 length of maxilla froni nostril). 

 d. Transverse width of mandible at base (across interranial space) not more 

 (usually less) than length of gonys. 

 e. Commissure, at highest point, decidedly above middle of lateral profile of 

 closed bill. (Hood Island, and Gardner Island near Hood.) 



Geospiza conirostris (p. 498) 

 ee. Commissure, at highest point, not decidedly, if any, above middle of lat- 

 eral profile of closed bill. 

 /. Wing shorter (not more than 80.01); bill narrower (less than 15.24 

 deep at base), with blunter tip. (Tower Island.) 



Geospiza propinqua (p. 499) 

 f. Wing longer (81.79 or more) ; bill stouter (16.76 or more deep at base), 

 with acute and attenuate tip. (Culpepper Island.) 



Geospiza darwini (p. 500) 

 dd. Transverse width of mandible at base (across interramal space) greater 



than length of gonys. (James Island. ) Geospiza bauri (jj. 500) 



bb. Culmen not more than 19.05 (usually much less); wing not more than 76.20 

 (usually much less). 

 c. Culmen not less than 15.24; depth of bill at base 9.40 or more. 

 d. Bill stouter and relatively larger; tarsus not more than 22.86. 

 e. AVing averaging more than 71.12, tail averaging more than 43.18, tarsus 

 averaging more than 21.59. 

 f. Wing averaging 72.64, culmen averaging 18.03, depth of bill averaging 

 14.22. (Chatham, Barrington, and Duncan islands.) 



Geospiza dubia (p. 501) 

 ff. AVing averaging 72.14, culmen averaging 17.27, depth of bill averaging 

 13.72. (Albemarle and Narborough islands.) 



Geospiza albemarlei (p. 502) 

 ee. Wing averaging not more than 71.12, tail averaging not more than 43.18, 

 tarsus averaging not more than 21.59. 

 /. Wing averaging 71.12, tail averaging 43.18, culmen averaging 17.27, 

 depth of bill averaging 12.95, tarsus averaging 21.59. (Charles, Dun- 

 can, Jervis, James, Gardner near Charles, Indefatigable, Chatham, and 



Cowley islands. ) Geospiza fortis (p. 502) 



ff. Wing averaging 65.79, tail averaging 41.15, culmen averaging 17.02, 

 depth of bill averaging 12.19, tarsus averaging 20.07. (Abingdon 



and Bindloe islands. ) Geospiza fratercula (p. 504) 



dd. Bill more slender and relatively much smaller; tarsus, 24.13 or more. 



(James Island.) Geospiza debilirostris (p. 508) 



ec. Culmen less than 15.24; depth of bill at 1)ase not more than 8.89. 



d. Maxillary tomium with a median or subterminal "tooth.'' (Charles 



Island. ) Geospiza dentirostris (p. 507) 



dd. Maxillary tomium not toothed. 

 e. Bill stouter (9.40 deep at base), with basal portion of culmen elevated 

 and strongly arched posteriorly. (Abingdon Island. ) 



Geospiza difficilis (p. 507) 



