170 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



" casque," or if not so developed the mesorhinium often distinctly flat- 

 tened, with its edges sharply defined. Commissure strongly and usually 

 abruptly deflexed for the basal portion, the maxillary tomium never 

 notched near tip. Nostrils never concealed, though sometimes (as in 

 the genus Mulothrus) the feathering of the loral antise extends beneath 

 them and covers the membrane immediately behind them; sometimes 

 (in the oropendolas and caciques) bored directly into the horny rhino- 

 theca, but usually situated in a more or less well-defined nasal fossa 

 and overhung by a more or less distinct (sometimes prominent and 

 corneous) membrane or operculum. Rictal bristles altogether obso- 

 lete or (in oropendolas and caciques) very faintly developed. Wing very 

 variable; usually with the tip moderatelj^ produced and subtruncate, 

 in one genus {Casi^idiir/) long (several times exceeding length of cul- 

 men) and the outermost (ninth) primary longest — in another {Amhly- 

 cercus) the longest primaries scarcely extending bej'ond the secondaries 

 and the outermost (ninth) primary shorter than the innermost (first); 

 tertials produced beyond secondaries only in some terrestrial genera 

 {Sttuviella, Trujnalis, Leistes, and Dolichonyx); outer webs of two to 

 five (eighth to seventh or fourth) primaries sinuated; inner webs very 

 variable, often not obviously sinuated, usually slightly so, soinetimes (in 

 IIohMjulscalu.'i and CnUothrus) the middle portion expanded (toothed in 

 Callothrus) ; longer primaries sometimes (as in Zarhynchus) attenuated 

 terminally. Tail variable as to relative length, form of tip, and shape 

 of rectrices; always more than half as long as wing, never conspicu- 

 ously longer than wing, never forked nor emarginate, usually more or 

 less rounded, sometimes double-rounded, occasionally (in Qwiscali) 

 graduated and plicate;^ usually the rectrices (always twelve in num- 

 ber) are of nearly equal width throughout, but sometimes (in Quiscali 

 and Agelaii) are wider terminally or (in some of the Cacici, and in 

 Sturnella) narrower terminally; in one genus {DolicJionysB) they are 

 abrubtly acuminate and rigid at tips, another genus {Leistes) show- 

 ing a slight approach to this charactei-. Acrotarsium alwaj^s dis- 

 tinctly scutellate, the divisions six to eight in number (the uppermost 

 usualh^ short and frequently hidden by overlapping feathers of the 

 tibia); length of middle toe and claw usually about equal to or slightly 

 shorter than the tarsus, never much longer nor conspicuously shorter; 

 claws of lateral toes usually reaching about to base of middle claw, 

 sometimes slightly beyond, in one genus {Xantliocephalus) considera- 

 bly beyond, sometimes (in Sturnella, Trupialis, Leistes, Xanthopsar 

 and most of the Quimill) falling decidedly short; hallux not longer 

 than lateral toes (except in Sturnella), usually a little shorter, frequently 



' This form of the tail in the Quiscali ia, so far as known, unique among birds; the 

 two halves of the tail are, at the bird's control, capable of being folded together so 

 that the edges are raised above the median line and brought more or less closely 

 together, a transverse section being V-shaped. 



