BIRDS OF NORTH AND MIDDLlI AMERICA. 305 



Genus SPIZELLA Bonaparte. 



Spizella Bonaparte, Saggio di una Distr. Met. An. Vert., 1832, 140. (Tj^pe, 



Fringilla pusilla Wilson. ) 

 Spinites^ Cabanis, Mus. Hein., i, April, 1851, 133. (Type,- Fringilla socicdis 



Wilson.) 



Small arboreal or semi-arboreal sparrows with small bill, long emar- 

 ginate or double-rounded tail, and back conspicuously streaked. 



Bill small (exposed culmen usually less than half as long as tarsus, 

 never much more), conical, much deeper than broad at base; depth at 

 base less than length of maxilla from nostril; culmen slightly convex 

 terminally and basalh^ straight or faintly depressed between; gonys 

 straight, about equal to basal depth of bill ; maxillary tomium without 

 subterminal notch, faintly concave anteriorly and convex posteriorly, 

 the basal deflection nearly or quite concealed by rictal feathers; man- 

 dibular tomium straight or slightly concave to the subbasal angle. 

 Nostril small, triangular (apex forward) or linear, only the anterior 

 portion exposed. Wing rather long (about three and one-fifth to four 

 and one-third times as long as tarsus), rather pointed (eighth to fifth 

 primaries longest, ninth shorter than sixth); primaries exceeding 

 secondaries usually by decidedly less than length of tarsus (by a little 

 more in S. socialis). Tail variable in proportionate length (decidedly 

 shorter than wing in nnonticola and socialis^ nearly as long in pusilla 

 and Ireioerl, and decidedly longer in atrogularis), deeply emarginated, 

 with the lateral rectrices nearly longest {socialis); double-rounded with 

 lateral feathers much shorter than the middle pair {atrogularis), or 

 intermediate (other species), the rectrices narrow, obtusely pointed at 

 tips, less than half overlaid by upper coverts. Tarsus moderate (usu- 

 ally more, rarely less, than twice as long as exposed culmen), its 

 scutella distinct; middle toe with claw slightly shorter than tarsus; 

 lateral claws not reaching to base of middle claw; hallux nearly equal 

 to inner toe, its claw shorter than the digit. 



Coloration. — Back and scapulars brownish, streaked with black; 

 lower back, rump, and upper tail-coverts plain grayish or grayish 

 brown, or else very indistinctly streaked; greater wing-coverts (and 

 usually middle coverts also) tipped, more or less distinctly, with white 

 or light brownish; lower parts plain whitish, grayish, or pale brownish 

 (belly always white) in adults, streaked with dusky in young (except 

 S. atrogularis). 



KEY TO THE SPECIES AND SUBSPECIES OF SPIZELLA. 



a. Chest without streaks. 



6. Pileum rufous or rusty, or else'gray tinged with rusty laterally, 

 c. A dusky spot in center of breast. 



' "Von dTiiva, r/ nom. prop." 



''In reality a substitute for Spizella, rejected as of bad or unclaasical construction. 



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