490 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



Coloration. — Fully adult uiales entirely black, including- })ill and 

 feet, but under tail-coverts with broad whitish or buff}^ margins; 

 innnature males, females, and young grayish brown streaked and 

 spotted with dusky above, beneath light colored with conspicuous 

 duskv streaks, the bill largelj^ light colored (except in some adult 

 females and innnature males). 



Range. — Peculiar to the Galapagos Archipelago. 



Few genera equal the present one in the extreme modifications in 

 the form of the bill, which in some s-pecies {magtiirost/'is, ^treniia, iind 

 puclryt'lujnclM) is perhaps not excelled by that of any other member of 

 the family Fringillida? in its extreme thickness, in others (members of 

 the so-called genus Cactornls) slender and decurved, in others very 

 acute, with straight outlines, and in others still elevated and arched at 

 the base. The most extreme forms are, however, so gradually and 

 perfectly connected b}^ intermediate types that there seems no possi- 

 bility of satisfactoril}^ subdividing the genus into two or more sections. 



The reduction of Cactornis to a synonym of Geospha has already 

 boon made in my paper describing the new species of Galapagos birds 

 in Dr. Baur's collection,^ in which is announced "the discovery of 

 species which absolutely bridge the previously existing gap between 

 the so-called genera Gcospiza and Cactornis., thus necessitating the 

 suppression of one of these names (the latter, according to the rule of 

 priority)."" 



While admitting that it would be very convenient to recognize 

 Cactornis if any definite characters could be found, I am still of the 

 opinion that not a single character can be depended on to separate 

 them. The character which comes nearest to doing so is, apparently, 

 the relative width of the mandible between the bases of the rami to 

 the length of the gonys, which is ver}' much less in topical '^Cactornis'''' 

 than in true Geosjnza. This greater compression of the bill even 

 serves to trenchantly separate " Cactornis'''' propinqua from G. cmiiros- 

 tris, some individuals of which are almost precisely' alike in the lateral 

 profile and measurements of the bill ; but the use of this character as 

 a generic one would necessitate the removal of Geospiza difficilis and 

 G. acutirostris, perhaps also G. minor, to Cactornis; and it is difiicult 

 to see how the group can be divided into two genera without one or 

 two more being necessary; for there is certainly more difference 

 between such species as Geospiza magnirostris and G. pacliyrlujncliaow 

 the one hand and G.fuUginosa., G. debiUrostris, etc., on the other, than 

 between '"''Cactornis'''' hrevirostris B,nd Geospisa Jratefxala, or between 

 C. propinqua and G. conirostris. Furthermore, if this group be 



* Descriptions of Twenty-two New Species of Birds from the Galapagos Islands, 

 Proo. U. S. Nat. Mus., xvii (advance sheets published November 15, 1894), pp. 

 357-370. 



