262 CLASS AVES. 



The proportional length of their wings, and the ex- 

 tent of their flight, are as variable as their mode of 

 life. 



Their sternum has usually but one slope on each 

 side at its lower edge. There are, however, two in 

 the rollers, the king-fishers, and the bee-eaters, and 

 none in the martinets and the coUbris. 



Our first division shall be founded on the character 

 of the feet^ and our subsequent ones on the beak. 



The first and most numerous division comprehends 

 the genera in which the external toe is united to the 

 internal, only by one or two phalanges. 



The first family of this division is that of the 



Dentirostres, 



Whose beak is sloped on the sides of the point. 

 In this family are found the greatest number of 

 insectivorous birds. Still, they almost all of them 

 also eat berries, and other tender fruits. 



The genera are determined by the general form of 

 the beak. It is strong and compressed in the shrikes, 

 and in the thrushes ; depressed in the fly-eaters ; 

 round and thick in the tanagers, slender and pointed 

 in the fine-beaks, &c. 



The Shrikes (Lamus, Linn.) Pie-Grieches, Cuv. 



Have the beak conical or compressed, more or less 

 crooked at the end. 



The Shrikes properly so called, (Pie-Grieches,) 

 Have it triangular at the base, compressed at the 



