NO. 1110. PROCEEDINGS OF THE NATIONAL MVSEVM. 545 



tious ill tlie form of the bill, both in this group and in Geospiza, being 

 very largely a specific character, therefore necessitating either a mate- 

 rial increase or rednctiou of the recognized number of genera within 

 the two groups. The differences in the form of the bill presented by 

 Camarhynehus, as here defined, from Geosjyka, while perfectly obvious 

 on comparison of specimens, are extremely difficult to describe, since 

 they result chiefly from variations of curvature in its outlines and rela- 

 tive proportions of various minor details hardly susceptible of exact 

 definition. 



The coloration exhibits much more obvious difference than form, none 

 of the species of Camarhynehus, so far as known, being entirely black 

 in the adult male; in fact none of them are black posterior to the chest 

 below or the hind neck above, while, with few exceptions, the immature 

 males and females are not distinctly streaked beneath. 



KEY TO THE SPECIES OF CAMARHYNCHUS. 



a'. Tomia strongly aiigulatecl and basal width of mandible greatly exceeding 

 length of gonys. {Plattjspiza.^) 

 hK Distinctly streaked with dusky below (Abingdon?, Bindloe?, Albemarle, 

 James, Indefatigable, Chatham, and Charles islands). 



1. C. rariegatus (p. 548), 

 (?)' ¥. Not distinctly streaked below f. (Charles Island?) 



2. C. crassirostris (p. 551). 

 «-. Tomia moderately or very slightly angnlated, and basal width of mandible 

 not greatly, if at all, exceeding length of gonys. 

 b\ Basal depth of bill e(|ual to or greater than length of maxilla from nostril. 

 (Camai'hynchus.) 

 c'. Basal width of mandible decidedly greater than length of gonys. 



d^. Larger (wing2.G5-3, culmen 0.55-0.61) and rather paler. (James, Jervis, 

 Indefatigable, and Charles islands).. 3. C. 2)sittaculus (p. 552). 

 d". Smaller (wing 2.50-2.75, culmen 0.50-0.57) and rather darker. (Albe- 

 marle Island) „ 4. C. affinis (p. 554). 



C-. Basal width of mandible not decidedly, if at all, greater than length of 

 gonys. 

 d\ Culmen 0.60 or more. 



e'. Larger, with stouter bill (wing 2.68 or more, culmen 0.62 or more). 

 /'. Rather smaller (wing 2.68-2.75), with smaller and weaker bill (cul- 

 men 0.62) and more compressed culmen ; wing-coverts in adult 

 male margined with light brown. (Abingdon Island.) 



5. C. haheJl (p. 555). 

 /-. Rather larger (wing 2.68-2.92), with larger and stouter bill (cul- 

 men 0.64-0.68) and broader culmen ; wiug-coverts in adult male 

 margined with olive. (Bindloe Island). 6. C. /jiwd/ofi (p. 556). 

 e". Smaller, with weaker bill (wing 2.57, culmen 0.60). (Jervis Island,) 



7. C. compressiroairis (p. 558). 

 d^. Culmen less than 0.60. 

 eK Wing 2.70 or more. (Charles Island) 8. C. pauper {-p. 559). 



'New subgenus: Type, Camarhynehus varief/aiiis. Sclater and Salvin. 

 2 The interrogation point signifies doubt as to whether this supjjosed species is 

 correctly placed in this section or subgenus. 

 Proc. N. M. vol. xix 35 



