BIRDS OF NORTH AND MIDDLE AMERICA. 187 



loral antisv to the rictus — the poi'tioii iinmediatelj^ })eneath the loral 

 antise sometimes slightly convex. Nostril on lateral median line of max- 

 illa or below (in typical species decidedly below), narrow, longitudinal, 

 bored directlj- into the horny rhinotheca, usually more or less beveled 

 anteriorly, the posterior end in contact with feathering of the loral 

 antiee. Wing moderate to long (about four to nearly five times as 

 long as culmen, about four and one-third to five times as long as tai'sus), 

 its tip rather short to long (much less than length of culmen to much 

 more), rounded; ninth (outermost) primary shorter than fifth (shorter 

 than third in C. leucorhamphns, equal to first in C chrysonotus) ; eighth 

 to sixth or (in O. chrysonotus) seventh to fifth longest, the eighth, 

 seventh, and sixth or (in C. chrysonotus) seventh, sixth, and fifth nearly 

 equal; in tj^pical species the longer primaries gradually, but not con- 

 spicuously, narrowed terminalh'. Tail nearly two-thirds to more than 

 seven-eighths as long as wing, or (in C. chrysonotus) longer than wing, 

 subemarginate, double-rounded, or graduated (graduation always less 

 than length of culmen). Tarsus shorter than culmen to slightly longer, 

 about one-fifth to two-ninths as long as wing, its anterior scutella dis- 

 tinct; middle toe, with claw, slightly to decidedlj^ shorter than tarsus; 

 lateral toes with claws reaching to or slightlj^ beyond base of middle 

 claw; hallux shorter than lateral toes or (in C. leacorhainphus and 

 C. chrysonotus) about as long, but much stouter, its claw decidedly 

 shorter than the digit; all the claws strongly curved, acute. 



Coloration. — Black, with a scarlet or yellow patch on rump; some 

 of the yellow-rumped species with a yellow patch on wing-coverts, 

 some with also the tail-coverts and base of tail yellow; sexes alike in 

 coloration. 



Range. — Nicaragua to western Ecuador, Bolivia, Paraguay, and 

 southern Brazil. (Eleven species, all South American, only two of 

 them reaching the Isthmus of Panama.) 



I have been strongly tempted to subdivide this genus by removing 

 at least C. chrysonotus., which diflfers strikingly in its weak bill, short- 

 tipped and much-rounded wing, long tail, and apparently different pro- 

 portionate length of the toes; but the only specimen of this species 

 that I have been able to examine is a young bird, and I can not be 

 sure that the peculiarities observed would be equally evident in the 

 adult. G. leucorlmmphm agrees in some characters with 0. chrysonotus., 

 though not to the same degree, and seems, on the whole, to be struc- 

 turally intermediate between that species and those with the tail-coverts 

 and base of tail yellow {C. j)ersicus, C. vitellinus, and C. flavicrissus). 



Cassicm albirostris Vieillot is also probably not a member of this 

 genus, and should without much doubt be placed in the genus Archi- 

 planus Cabanis, of which it is the type and only known species. Of 

 this species I have seen only the female, which is a very small bird 

 (less in size than the average Icterus), with a decidedly wedge- 



