Class n. GREEN WOODPECKER. 317 



body of the tree. In order, therefore, to force 

 their way to those cavities, their bills are formed 

 strong, very hard, and wedge-like at the end ; 

 Dr. Derham observes, that a neat ridge runs 

 along the top, as if an artist had designed it for 

 strength and beauty ; it has not the power to 

 penetrate a sound tree: their perforation of 

 any tree is a warning to the owner to throw it 

 down. 



Their legs are short, but strong ; their thighs 

 very muscular ; their toes disposed, two back* 

 wards, two forward ; the feathers of the tail are 

 very stiff, sharp pointed and bending down- 

 wards : the three first circumstances admir- 

 ably concur to enable them to run up and down 

 the sides of trees with great security ; and the 

 strength of the tail supports them firmly when 

 they continue long in one place, either where 

 they find plenty of food, or while they are form- 

 ing an access to the interior part of the timber. 

 This form of the tail makes their flight very 

 awkward, as it inclines their body down, and 

 forces them to fly with short and frequent jerks 

 when they would ascend, or even keep in a line. 

 This species feeds oftener on the ground than ~ . 

 any other of the genus. 



This kind weighs six ounces and a half: its Descrip- 

 length is thirteen inches ; the breadth twenty 



