BIKDS OF NOETH AND MIDDLE AMERICA. 33 



gg. Commissure shorter than middle tue without eluw, or else tip of 

 maxilla not uncinate. ^ 

 h. Species mostlj- of unic(_>lored plumage, or else jxirticolored and the 

 colors bright; the adult males blue, slate color, black or yellow, 

 sometimes with two or more of these colors combined; some- 

 times black with chestnut or rufous areas (but with tail shorter 

 than wing); only the females and young dull colored, and these 

 very rarely streaked beneath. {Oryzoboren'.'^) 

 i. Bill exceedingly broad and thick, the width of mandible at base 

 decidedly greater than distance from nostril to tip of maxilla. 



Oryzoborus (p. 603) 



(/. Bill narrower, the width of mandible at base not decidedh', if at 



all, greater than distance from nostril to tip of maxilla. 



j. Culmen (from concealed base) equal in length to tarsus, or else 



outermost (ninth) primary shorter than third; adult males 



plain (mostly dull ) blue Cyanocompsa (p. 594) 



jj. Culmen (from concealed base) sliorter than tarsus; adult males 

 not blue, or else outermost (ninth) primary longer than 

 third. 

 k. Mandible conspicuously deeper than maxilla, or else culmen 

 strongly convex, the maxilla subfalcate. 

 /. Width of maxilla at base much less than basal depth of bill. 

 ///. Wing more than 63.50 mm.; plumage not blackish. 

 //. Greatest depth of mandible less than half its length. 

 (I. Distance from nostril to tip of maxilla much more 

 than one-third length of tarsus; adult males with 



more or less of l)lue Cyanospiza (p. 580) 



<Mi. Distance from nostril to tip of maxilla scarcely, if 

 at all, more than one-third length of tarsus; 

 adult male without any blue (olive-green, with 

 l)lack head, yellow carpus, and rufous under 



tail-coverts) Loxipasser ( p. 545) 



?(/(. Greatest deptli of mandible at least one-half its 



length; plumage blackish Melopyrrha (p. 561 ) 



//(//(. Wing less than 63.50 mm Sporophila (p. 563) 



//. Width of maxilla at base e(iual tn liasal depth of bill. 



Amaurospiza (]). 579) 



/.•/.-. ^Mandible not conspicuously deejier than maxilla, the latter 



not subfalcate or with culmen strongly curved (the latter 



sometimes nearly straight) . 



/. Bill longer (distance from nostril to tip of maxilla equal to 



half length of tarsus) ; adult males uniform slate color. 



///. Bill more slender (depth at base much less than half 



length of commissure) Acanthidops (j). 517) 



^ See footnote on page 32. 



- A satisfactory group name can not be derived from any of the genera, and the one 

 adopted is selected as being the least objectionable of any that may be so derived. 

 The group is not a strictly homogeneous one, but I have not been able to satisfac- 

 torily subdivide it. The characters given above are confessedly unsatisfactory, but, 

 although the group as a whole is obviously distinct from any of those which follow, 

 I am unable at present to construct a better diagnosis. (See arrangement on page 

 28, where an attempt at subdivision is made. ) 



17024—01 -3 



