336 



SNODGRASS AND HELLER 



invariably characterizing birds of the age of Stage II of the other sub- 

 genera. 



69. THE GEOSPIZA SCANDENS SERIES. 



The variation in the shape and size of the bill in this series amounts 

 to but little. We begin with the smallest billed variety which follows 

 naturally G. septentrional is, and end with the largest billed form, G. 

 scandens rothschildi, which leads easily into G. conirostris pro- 

 pinqua, and this into the again conical billed form, G. conirostris 

 conirostris. 



The plumage of the varieties of G. scandens differs from that of 

 any of the forms so far described in that the adult females and the 

 young present a strongly melanistic phase. Adult females instead of 

 being pale brown spotted forms as in G.fuliginosa and G.fortis 

 are continuously dusky over the back, head, and throat, corresponding 

 with Stage V of immature males of G. fuliginosa instead of with 

 Stage III as do the adult females of this species. Young birds of 

 both sexes soon after leaving the nest acquire the same dusky plumage of 

 the adult females except that they have the rufous borders to the wing 

 coverts characteristic of birds of their age. The varieties from Abing- 

 don and Bindloe present the maximum of this melanistic tendency in 

 the female and young reached by any forms of the species. The next 

 species, however, G. conirostris, is still blacker in these forms and 

 represents the farthest advance toward complete melanism attained by 

 the genus. 



The forms now included under the species G. scandens were regarded 

 by Gould as constituting a distinct genus, Cactornis. The intergra- 

 dations at each end with other forms, however, are, as has already been 

 recognized by Ridgway and by Rothschild and Hartert, unbroken. 

 Rothschild and Hartert regarded Camarhynchus pallida as being 

 intermediate between the genera Camarkynckus and Geospiza. This 

 may be true of the bill, but, as we have already shown, the plumage 

 of C. pallida separates it widely from any species of Geospiza, and 

 especially from those which it most resembles in the shape of the bill. 



690. GEOSPIZA SCANDENS SCANDENS (Gould). 



Cactornis scandens GOULD, Proc. Zool. Soc. Lond., p. 7, 1837 (James Island) ; 



Zool. Voy. Beagle, Birds, p. 104, pi. 42, 1841. 

 f Cactornis assimilis GOULD, Proc. Zool. Soc. Lond., p. 7, 1837 (? Charles 



Island according to Rothschild and Hartert, Bindloe Island according to 



Gould which cannot be correct) ; Zool. Voy. Beagle, Birds, p. 105, pi. 



43, 1841. 



