BIRDS OF NORTH AND MIDDLE AMERICA. 407 



aa. Tail much more than half (three-fifths to two-thirds) as long as wing; tarsus not 

 shorter than inner toe without claw; malar apex not nearer to eye than to nos- 

 tril; coloration not exclusively black and white. 

 6. Exposed culmen not more than one-third as long as wing; gonys less than half 

 as long as mandibular rami; depth of bill at middle of nostril equal to one- 

 third the distance from nostril to tip of maxilla; bill less tapering terminally, 

 more obtuse at tip, the culmen more decurved terminally; tarsus not longer 

 than inner toe without claw; coloration white, the upper parts barred with 



black and bluish gray Megaceryle (extralimital) .« 



bb. Exposed culmen more than one-third as long as wing; gonys more than twice as 

 long as mandibular rami; depth of bill at middle of nostrils less than one- 

 third the distance from nostril to tip of maxilla; bill more tapering terminally, 

 the tip acute, the culmen less decurved terminally; tarsus longer than inner 

 toe without claw; coloration not mostly white. 

 c. Exposed culmen less than half as long as wing; ninth primary longer than 

 seventh; feathers of crown (as well as those of occiput and nape) elongated 

 and narrow; upper parts mostly bluish gray (without metallic green). 



Streptoceryle (p. 407). 



cc. Exposed culmen more than half as long as wing; ninth primary shorter than 



iseventh; feathers of crown and occiput short and blended (except in C. 



amazona) ; upper parts metallic bronze green Chloroceryle (p. 421). 



Genus STREPTOCERYLE Bonaparte. 



Ispida (not of Brisson, 1760, Schaeffer, 1789, nor Rafinesque, 1815) Swainson, 

 Classif. Birds, ii, 1837, 326. (Type, Alcedo alcyon Linnaeus.) 



Streptoceryle Bonaparte, Ateneo Italiano, ii, 1854, 320 (Consp. Volucr. Anisod., 

 1854, 10). (Type, Alcedo torquata Linnaeus.) 



Ichthyonomus Cabanis and Heine, Mus. Hein., ii, Jan., 1860, 150. (Type, Alcedo 

 maxima Pallas.) 



Medium sized to very large AlcedinidsB (length about 300-450 

 mm.) with the exposed culmen more than one-third but less than half 

 as long as wing, gonys more than twice as long as mandibular rami, 

 ninth primary longer than seventh, feathers of crown (as well as those 

 of occiput and nape) elongated and narrow, and general color of 

 upper parts bluish gray. 



Bill longer than head, stout, compressed, its depth at middle of 

 nostrils equal to about one-fourth the length of exposed culmen and 

 much greater than its width at same point; cuhnen straight or very 

 nearly so to near tip where very shghtly decm'ved, forming a broad, 

 sometimes flattened, ridge, the basal half, more or less, margined 

 laterally by a well-defined but broad and shallow groove, from the 

 nasal fossse forward; gonys more than twice as long as mandibular 

 rami, more or less prominent and convex (sometimes subangular) 

 basally, nearly straight or faintly convex for rest of its length, 

 ascendmg terminally; commissure straight, or very nearly so, for 

 most of its length, but maxillary tomium strongly convex basally, 



o Megaceryle Kaup, Verh. naturhist. Vereins Hessen, ii, 1848, 68. (Type, Alcedo 

 guitaius Vigors (not of Boddaert)=.4. lugubris Temminck.) 

 Eastern Asia. (Monotypic.) 



