28 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



ment is in this, as in so many other cases, practically impossible/ The 

 key is therefore confessedly to a large extent artificial, the main object 

 sought being the easy identification of the genera. 



KEY TO THE GENERA OP PKIKGILLID^. 



a. Mandibular rami very short (less than one-fifth as long as gonys); width of man- 

 dible at base nearly equal to length of gonys (sometimes greater); nasal fossae 

 obsolete, the nostril bored directly into basal lateral margin of the horny rhino- 

 theca; commissure not abruptly deflexed basally, or else'' basal width of man- 

 dible greater than length of gonys. ( Coccothraustex. ) Hesperiphona (p. 37) 



aa. Mandibular rami longer (at least one-third as long as gonys); width of mandible 

 at base much less than length of gonys; nasal fossse more or less obvious (some- 

 times, however, hidden by small feathers); commissure abruptly deflexed 

 basally. 

 b. Mandibular rami less than one-half as long as gonys; nasal fossse shorter, more 

 or less hidden by tuft of antrorse latero-frontal plumules, 

 c. Maxilla and mandible with tips falcate and crossed. {Loxise. ) . . .Loxia (p. 46) 

 cc. Maxilla and mandible with tips neither falcate nor crossed. 



d. Culmen strongly curved; bill very short and thick, the distance between 

 nostrils not less than half the length of gonys. ( Pyrrhulse. ) 

 c. Width of mandible at base greater than length of maxilla from nostril; 

 pileum (or at least forehead) black; wings and tail at least partly pur- 

 plish black Pyrrhnla (p. 56) 



ee. Width of mandible at base less than length of maxilla from nostril; pileum 

 without black; wings and tail without purplish black. .Finicola (p. 58) 



^The arrangement followed in the following pages is as follows: 



Group CoccothratiBteae. — Genus Hesperiphona. 



Group Loxiffi. — Genus Loxia. 



Group Pyrrhulse. — Genera Pyrrhuia, Pinicola. 



Group Fringillse.— Genera Leucosticte, Acanthis, Oarduelis, Spinus, Loximitris, 

 Astragalinus, Carpodacus, Passer. 



Group Caloariese. — Genera Passerina, Galcarius, Rhynchophanes. 



Group Calamospizse. — Genus Oalamospiza. 



Group Spizae. — Genus Spiza. 



Group ChondestesB. — Genera Chondestes, Pooecetes. 



Group Ammodrami. — ^Genera Passerculus, Centronyx, Ooturniculus, Ammodramus. 



Group Zonotricliiae. — Genera Plagiospiza, Aimophila, Amphispiza, Junco, Spizella, 

 Zonotrichia, Brachyspiza, Melospiza, Passerella, Oreospiza, Pipilo, Melozone, 

 Arremonops, Arremon, Lysurus, Atlapetes, Buarremon, Pselliophorus, Pezopetes. 



Group GeospizBB, — Genera Platyspiza, Camarhynchus, Geospiza, Cocornis. 



Group Haplospizse, — Genera Acanthidops, Haplospiza, Sicalis, Euetheia, Melano- 

 spiza. 



Group SporopMlse. — Genera Loxipasser, Pyrrhulagra, Melopyrrha, Sporophila, 

 Amaurospiza. 



Group Cyauospizae. — Genera Cyanospiza, Gyanocompsa. 



Group Oryzoboreae. — Genus Oryzoborus. 



Group Guiracae. — Genera Giiiraca, Zamelodia, Pheucticus. 



Group CardinaleBB. — Genera Pyrrhuloxia, Cardinalis. 



Group Pitylese. — Genera Pitylus, Caryothraustes, Rhodothraupis, Saltator. 



^ In the Asiatic genus ilycerobas. 



