50 AVES. 



at the tip : cere hispid : nostrils rounded, or lunulate : 

 wings long. 



(1. AQUILA.) Tarsi feathered to the toes : claws unequal, grooved 

 beneath: fourth quill longest. 



(2. HALI^EETUS.) Tarsi half-feathered; acrotarsia scutellated: claws 

 unequal, grooved beneath : fourth quill longest : nostrils trans- 

 verse. 



(3. PANDION.) Tarsi naked; acrotarsia reticulated with small 

 rounded scales : outer toe reversible : claws equal, rounded 

 beneath: second quill longest. 



3. FALCO Bill short, strong, bending from the 



base; upper mandible strongly toothed, lower one emar- 

 ginated : nostrils round : tarsi short and strong ; acrotarsia 

 reticulated : wings long ; second quill longest ; first and 

 second with the inner webs deeply notched near the ex- 

 tremity. 



4. ACCIPITER Bill short, rather strong, bending 



from the base : nostrils oval : tarsi slender ; acrotarsia 

 scutellated : middle toe much longer than the lateral ones : 

 wings short, not reaching beyond two-thirds of the length 

 of the tail: fourth quill longest. 



(1. ASTUR.) Tarsi moderate ; rather robust : acrotarsia scutellated. 



(2. ACCIPITER.) Tarsi long and slender: acrotarsia scutellated; 

 the sutures of the scales obsolete. 



5. MILVUS Bill moderate, rather weak, bending 



slightly from the base, somewhat angular above: nostrils 

 oblique, oval or elliptic : tarsi short : toes and claws weak : 

 wings very long : tail long, and forked. 



(1. MILVUS.) Tarsi feathered a little below the knee; acrotarsia 

 scutellated: fourth quill longest. 



(ELJNUS.) Tarsi very short, half- feathered ; acrotarsia reticulated : second 

 quill generally the longest. 



6. BUTEO Bill moderate, bending from the base : 



nostrils oval or roundish : tarsi partly naked, or clothed 

 with feathers: wings long; third and fourth quills gene- 

 rally the longest; the four first emarginated on their inner 

 webs: tail even. 



(1. BUTEO.) Lore without feathers : tarsi short and strong ; naked, 

 with the acrotarsia scutellated ; or feathered to the toes. 



