170 BULLETIN .lO, UNITED STATES NATIONAL MUSEUM. 



"(•usque, " or if not so developed the mesorhiiiiimi often distinctly flat- 

 tened, with its edges sharply defined. C'oniniissure stron^-ly and usually 

 abruptly deflexed for the basal portion, the maxillary tomium never 

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

 the genus MoJothrus) the feathering- of the loral antia? extends l)eneath 

 them and covers the membrane immediately l)ehind them; sometimes 

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

 theca, but usually situated in a more or less well-d(»fined nasal fossa 

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

 corneous) membrane or operculum. Kictal ])ristles altogether obso- 

 lete or (in oropendolas and caci<|ues) very faintly (levelo})ed. Wing very 

 variable; usually with the tip moderately procUiced and subtruncate, 

 in one genus {('assidir) long (several times exceeding length of ciil- 

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

 cerciis)X\ie longest primaries scarcely extending beyond the secondaries 

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

 tertials produced beyond secondaries only in some terrestrial genera 

 {SturneUa^ Trupialls, Leisfes^ and Dolic/ioai/./'); outer webs of two to 

 live (eighth to seventh or fourth) primaries sinuated; inner webs ver}" 

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

 Iloloquiscahis and C'l/I/othrus) the middle portion expanded (toothed in 

 CaJJothrus)\ longer primaries sometimes (as in Zarhynclm^) attenuated 

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

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

 ousl}'^ longer than wing, never forked nor emarginate, usually more or 

 less rounded, sometimes double-rounded, occasionally (in Qi(hcali) 

 graduated and plicate;' usually the rectrices (alwaj^s twelve in num- 

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

 and Agelaii) ai'e wider terminally or (in some of the Cacir/\ and in 

 Sturnella) narrower terminally; in one genus {Dollchom/.i^ they are 

 a])rubtly acuminate and rigid at tips, another genus {Leistes) show- 

 ing a slight approach to this charactei'. Acrotarsium always dis- 

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

 usually short and frecpiently hidden by overlapping feathers of the 

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

 shorter than the ttirsus, never nuu-h longer nor cons})icuously shorter; 

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

 sometimes slightly beyond, in one genus {X(()itJiovrp}i<iJns) considera- 

 bly t)eyond, sometimes (in Sturndla^ Tnipiufix^ Lehtei<^ Xanthopxnr 

 and most of the Qui^oili) falling decidedly short; hallux not longer 

 than lateral toes (except in Sifartwlhi)^ usually a little shorter, frecjuently 



'This form of the tail in the (^luscali is, so far as known, unique among birds; the 

 two halves of the tail are, at the bird's control, (•aj)abk' of l)eiiig folded tojjetlier so 

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

 together, a transverse section being V-shaped. 



