BIRDS 287 



On these olive-yellowish specimens there is not enough brown be- 

 low on the feathers to give the color of the spotted immature form 

 merely by a wearing away of the paler marginal parts of the feathers. 

 Hence, there must be, as in the case of G. pallida^ a moult inter- 

 vening between the olive-yellow stage and the spotted stage involving 

 a change in the color of the feathers. When feathers are acquired 

 having large subterminal brown spots the olive above and the yellowish 

 below may yet, however, be indefinitely retained through not being 

 worn off so as to expose the brown. 



Our specimens were taken at Iguana Cove, Albemarle, in Decem- 

 ber and March ; at Tagus Cove, Albemarle, in June ; on James in 

 April, and on Duncan and Charles in May. 



This is the smallest species of the subgenus CamarJiytichus and one 

 of the smallest of the Geospizce, being about the same size as G. fulig- 

 inosa. The bill is nearest in shape to that of the subgenus Geosptza 

 and probably represents the first step in the bill variation along the 

 Catnarkynchus line. 



The following two pairs of specimens were taken mated with each 

 other: Nos. 4246-4268, 4532-4554. 



553. GEOSPIZA PROSTHEMELAS SALVINI (Ridgway). 



Camarhytichus salvini Ridgway, Proc. U. S. Nat. Mus., xvii, p. 364, 1894 

 (Chatham Island), and xix, p. 561, 1896; Bull. U. S. Nat. Mus., 50, Pt. 

 I, p. 486, 1901. 



Geospiza salvini Rothschild and Hartert, Novit. Zool., vi, p. 169, 

 1899. 



Range. — Chatham. 



This form is very close to G. p. prosthemelas^ averaging slightly 

 larger with a heavier bill, approaching G. paupera in size. 



The collection contains seven adult specimens from Chatham taken 

 in May. Five are apparently adult males, one of which has the head 

 and throat black, but the color does not extend so far down on the 

 chest and sides as it does in most of the adult males of G. p. pros- 

 themelas. The other males, apparantly immature in plumage, are 

 streaked below anteriorly, being in the plumage described as adult 

 by other authors. Our specimens are no more olivaceous than those 

 from Albemarle, but are considerably more so than those from 

 James. 



The Charles Island specimens of G. p. prosthemelas is intermediate 

 in size between G. p. salvini and G. p. prosthemelas of the other 

 islands, although some specimens from most of the islands within the 

 range of the latter species are equal to G. p. salvini in size. 



