BIRDS OF NORTH AND MIDDLE AMERICA. 705 
g. Mandible very narrow (at gonydeal angle only about half as deep as 
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. 
4. Without any crest; a deciduous compressed supranasal knob in 
breeding season ........... 2-00-20 eee eee eee ee Ciceronia (p. 767). 
ui. 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, asin Alcella). 
Zithia (p. 774). 
ee. Larger (wing more than 165 mm.); rectices 16-18; acrotarsium with trans- 
verse scutella on Iower 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). 
6b. 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 righi 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. (Fraterculinez.) 
¢. 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 horny 
‘appendages; head without ornamental plumes; under parts white. 
Fratercula (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 
PAPts GUSKY ac sewiwaiaenaswcicis cis eee ene ane ces maser Lunda (p 792). 
40017—19—Bull. 50, pt 846 
