34 FORM AND HABIT: THE BILL. 



that of the female is long and curved. The birds feed 

 on larv£e, which they find in dead wood. The male 

 hammers and chisels away the wood veiy much as Wood- 

 peckers do, while the female uses her hill as a prolje. 

 We have, therefore, the sing-ular case of two forms of 

 the bill arising in the same species as a result of or caus- 

 ing a corresponding difference in habit. 



