BIRDS OF NORTH AND MIDDLE AMERICA. 455 



except terminally and basally, where gently convex, or gently convex 

 throughout; gonys straight, a little shorter than distance from nostril to 

 tip of maxilla; maxillarj' tomiumwith suliterminal notch indistinct or 

 obsolete, very fainth^ concave anteriorly and convex posteriorly in front 

 of the moderately abrupt but decided basal deflection; mandibular 

 tomium straight or faintly convex to the very distinctly toothed sub- 

 basal angle. Nostril small, longitudinally or obliquely oval. Rictal 

 bristles obvious but not conspicuous. Wing short (two and a half to 

 less than three times as long as tarsus), \'cry much rounded (seventh to 

 fifth primaries longest, ninth shorter than secondaries); primaries 

 exceeding secondaries by much less than length of maxilla from nostril. 

 Tail shorter than wing, much rounded, much less than half overlaid by 

 upper coverts. Tarsus long (much more than twice as long as maxilla 

 to nostril), its scutella indistinct on outer side; middle toe with claw 

 decidedly shorter than tarsus; lateral claws not reaching to base of 

 middle claw; hind claw nearly as long as its digit, strongly curved. 



Coloration. — Above plain olive, olive-green, or gra}^ the pileum 

 black with or without a median stripe of grayish; sides of head black, 

 with or without a white supra-auricular or superciliarj' stripe; beneath 

 white, shading into grayish or olivaceous laterally, the chest usually 

 crossed by a black band; edge of wing- usually yellow. Sexes alike. 



Range. — Neotropical region in general, except Antillean Subregion, 

 but chiefly developed in tropical South America. 



Notwithstanding Amnion has by common consent been referred to 

 the Tanagridfe, I can not find any essential structural difference 

 between the type {xi. silens) and the Central American sparrows 

 usually referred to JEmbernagra {=Arivrnonojj><)^ while the style of 

 their coloration is essentially the same — far more so, indeed, than the 

 similarity of coloration between the different species of certain other 

 recognized genera (e. g. , Aiinophllu and Pljjilo). A. auraiitiirostris., the 

 onlj' species found north of the Isthmus of Panama, is not very dissim- 

 ilar to the type of the genus (^i. silens) in coloration, far less so, in fact, 

 than are many of its South American congeners; but it diflers in some 

 respects as regards structural details, the bill being considerably stouter, 

 with distinctly curved instead of nearly straight culmen, and the rectrices 

 are proportionally rather broader. A. silens has a black bill, that of 

 A. cmrantiirostrh being wholly bright orange-red (fading to yellowish 

 in dried skins), while other species have the bill partly black and partly 

 orange or yellow. 



ARREMON AURANTIIROSTRIS Lafresnaye. 

 ORANGE-BILLED SPARROW. 



Adults {sexes alil'e). — Pileum black, with a median stripe of gray; 

 a rather narrow superciliary stripe of pale gray (white in middle por- 

 tion); sides of head, including malar region, and chin black; throat. 



