SUBFAMILIES AND GENERA 5 



of convenience rather than of anatomical necessity, are fairly easily 

 divisible by simple characteristics in outward form. 



Key to the Genera. 



A. A deep notch in inner web of third primary ; tail neither 



greatly graduated nor with central tail-feathers 

 prolonged : 



a. Homy part of bUl does not extend along cuhnen to 



edge of feathers of fore-head : 

 a' First three primaries acuminate, legs yellow Grocojms. 



V First three primaries not acuminate ; legs red : 

 a" Homy part of biU less than two-thirds 



of culmen Osmotreron. 



h' Homy part of bill more than two-thirds 



of culmen Butreron. 



b. Homy part of bill extends along the culmen to the 



feathers of fore-head Treron. 



B. Inner web of third primary with no notch; tail much 



graduated and lengthened Sphenocercvs. 



