BIBDS OF NORTH AND MIDDLE AMEBIOA. 33 



There is great difference in the form of the bill between B. ouoidlata, 

 B. montana^ B. arcml (and its close ally B. caruleigularii) on the one 

 hand and B. chloronota and B. eximia on the other, the two last 

 named having this member much shorter and proportionally deeper 

 at the base, the extreme abbreviation existing in B. eximia. In the 

 last-named species the gonys is sharply ridged, and there is a very 

 slight development of the uncinate tip to the maxilla, which in 

 B. chloronota is quite as well developed as in B. cucuUata, the gonys 

 at the same time lacking the well-defined ridge of B. eximia. On the 

 other hand B. arccei and B. cwruleigularis, with even a more slender 

 bill than B. cucullata., have the tip of the maxilla even less uncinate 

 than B. eximia. It will be seen, thei'efore, that the genus can not be 

 subdivided on the shape of the bill alone without making four groups, 

 the first to include B. cucullata and B. montana., the second B. arcwi 

 and B. cceruleigularis, the third B. chloronota., and the fourth B. eximia. 



The first-mentioned of these groups is further characterized by 

 having the plumage of the upper parts (the head excepted) remarkably 

 glossy. The others have the upper plumage normal in this respect, 

 except that represented bj^ B. eximia, which has the pileum glossy 

 and the rump partially so. The group containing B. arcmi and B. 

 cmruleigularis {B. edwardsi also?) has the tail very much shorter in 

 proportion to the wing than the others. 



It m.2ij eventually prove necessary to separate one or more of these 

 groups on account of the characters mentioned, but for the present I 

 prefer to leave the genus with usually assigned limits. 



BUTHRAUPIS ARC^I Sclater and Salvin. 

 AROE'S TAWAGER. 



Aokilt male. — Above dull grayish indigo blue, the wings and tail 



blackish with dull indigo blue edgings; lores, chin, and throat dull 



blackish, tinged with dull indigo bluish; rest of under parts rich 



yellow (saffron or Indian yellow on chest, gradually fading to lemon 



yellow on under tail-coverts), the sides and flanks mottled or clouded 



with dusky; under wing-coverts pale yellow, with concealed dusky 



spaces on outer webs; bill blackish; legs and feet horn brownish; 



length (skin), 14Y.3;' wing, 85.6; tail, 72.6; exposed culmen, 15.2; 



depth of bill at base, 8.6; tarsus, 22.4; middle toe, 16. 



Veragua (Cordillera del Chucu; Calobre). 



Bulhraupis arcid Sclater and Salvin, Proc. Zool. Soc. Lond., 1869, 439, pi. 31 



(Cordillera del Chucu, Veragua; coll. Salvin and Godman).— Salvin, Proc. 



Zool. Soc. Lond., 1870, 187 (Cordillera del Chucu). -Salvin and Godman, 



Biol. Centr.-Am., Aves, i, 1883, 276 (Cordillera del Chucu and Calobre, 



Veragua).— Sclater, Cat. Birds Brit. Mus., xi, 1886, 149. 



[Buthraupls] arcxi Sclater and Salvin, Nom. Av. Neo tr., 1873, 20. ^ 



iThe total length is actually much greater, the skin being greatly shortened, 



3654r— VOL 2—01 3 



