342 SNODGRASS AND HELLER 



Hence there is almost a perfect gradation through this subspecies 

 from the slender billed Cactorftis group to the next species, G. coni- 

 rostris, which ends at the top of the Geospiza series with a bill 

 again enlarged and conical and with very dark plumage in the adult 

 female and young. 



The remarks on the plumage of G. s. abingdoni apply also to this 

 form. 



This species is not common. All our specimens were taken about 

 the middle of June. We did not even see any adult individuals. 



70. THE GEOSPIZA CONIROSTRIS SERIES. 



This species presents probably the greatest variation in the size and 

 shape of the beak of any of the species of Geospiza. Two apparently 

 well separated species were formerly described by Ridgway from the 

 extremes of one subspecies., G. c. conirostris., living on Hood. The 

 bill in shape resembles that of G. f. fortis., differing from it at one 

 end of the series, mainly in being larger. The species comprises two 

 subspecies, of which G. c. conirostris of Hood has the larger and more 

 conical beak, resembling in shape that of G. f. fortis; while the 

 other, G. c. propinqiia of Tower and Culpepper, has a more slender 

 beak resembling in shape that of G. septentrionalis of Culpepper and 

 in both shape and size in some cases that of G. scandens I'othscJiildi oi 

 Bindloe. The size of the bill of an average specimen measures as fol- 

 lows : Culmen 22, gonys 1 1.5, width of bill at base I3, depth at base 

 16.5. The variations are as follows: Culmen 19 to 24, gonys 10 to 

 14, width of bill at base 10 to 13.5, depth at base 13 to 18. All of 

 these variations in size occur within the subspecies G. c. conirostris., 

 but the bill of G. c. propinqua averages smaller than that of G. c. 

 conirostris. 



The plumage of this species presents the farthest advance toward 

 complete melanism, i. e.^ of both sexes and all ages, attained by any 

 species of Geospiza. It reaches a stage farther in the females and 

 young than it does in the last species. The adult females have a 

 greater amount of dusky on them than do males of G. ftiliginosa., G. 

 fortis., etc., in Stage IV, since the belly, instead of being mostly pale, 

 is heavily streaked with dark brown. The back, head, throat and 

 breast are continuously blackish-brown, except that the feathers of the 

 back have slight brownish edgings. The young soon after leaving the 

 nest resemble the females. 



The fact that the beaks of the smallest billed individuals of this 

 species are so close in shape and size to those of the largest billed in- 



