Class II. 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. Derkam 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 V erv 

 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 



