BIEDS OF NORTH AND MIDDLE AMERICA. 705 



g. Mandible very narrow (at gonydeal angle only about half as deep aa 

 maxilla), strongly recurved to the acute tip; culmen and maxillary 

 tomium strongly, regularly, and about equally convex; tip of the 

 maxilla truncate or subtruncate; feathering at lateral base of maxilla 



forming a distinct angle or latero-frontal antia Phaleris (p. 763). 



gg. Mandible deeper (at gonydeal angle much more than half as deep as 

 maxilla, not recurved, or else its tip not acute; culmen and max- 

 illary tomium not equally convex, the latter sometimes nearly 

 straight and if convex irregularly so; tip of maxilla obtusely 

 pointed; feathering at lateral base of maxilla forming an oblique 

 line to base of culmen, not forming a latero-frontal antia. 

 h. Bill relatively smaller, with exposed culmen more than half as 

 long as commissure and much longer than gonys; tomia nearly 

 straight, the mandible not recurved terminally; no supra-rictal 

 deciduous plate nor ramal enlargement during breeding season; 

 head with loral and post-rictal acicular plumes in adults. 

 i. Without any crest; a deciduous compressed supranasal knob in 



breeding season Ciceronia (p. 767), 



n. With a slender, elongated and recurved frontal crest; no supra- 

 nasal knob in breeding season Alcella (p. 770). 



hh. Bill relatively larger, with exposed culmen less than half as long 

 as commissure and not longer than gonys; maxillary tomium 

 irregularly convex, the mandibular tomium irregularly concave; 

 tip of mandible recurved, with tip obliquely truncate; a decid- 

 uous supra-rictal corneous plate and conspicuous enlargement 

 of mandibular rami; head without loral or post-rictal plumes 

 (but with an elongated, recurved frontal crest, as in Alcella). 



-ffithia (p. 774). 

 ee. Larger (wing more than 165 mm.); rectices 16-18; acrotarsium with trans- 

 verse scutella on lower portion; longest primary exceeding distal 

 secondaries by more than half the length of wing; bill much longer 

 than distance from posterior end of nostril to tip of maxilla, nearly if not 

 quite equal to length of tarsus. (A conspicuous compressed supra-nasal 



"horn" in breeding season) Cerorhinca (p. 778). 



66. Claw of inner toe conspicuously larger, more strongly curved, and more acute 



than those of middle and outer toes; thigh-muscle formula AX+; syrinx 



peculiar; liver with lobes equal or the right lobe larger than the left; 



rectrices 16; bill excessively deep and compressed, its height at base equal 



to chord of culmen, the terminal half conspicuously grooved (transversely), 



the basal portion with several deciduous parts. (Fraterculinse.) 



c. Deciduous nasal cuirass or "saddle" diminishing in width toward culmen, 



its anterior outline more or less convex; strongly oblique maxillary grooves 



convex distally (anteriorly); basal lamina of maxilla of equal width 



throughout, or slightly wider above than below; eyelids with homy 



appendages; head without ornamental plumes; under parts white. 



Fratercida (p. 782). 

 cc. Deciduous nasal cuirass broadest toward culmen, where surmounted by 

 a broadly rounded ridge, its anterior outline concave; nearly vertical 

 maxillary grooves concave distally (anteriorly); basal lamina of maxilla 

 much broader below than above; eyelids without horny appendages; 

 head with conspicuous, elongated, decurved postocular plumes; under 



parts dusky Lunda Cp 792). 



40017— 19— Bull. 50, pt 8 16 



