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 S4: FORM AND HABIT: THE BILL. that of the female is long and curved. The hirds feed on larvae, which they lind in dead wood. The male hammers and chisels away the wood very much as Wood- peckers do, while the female uses her bill as a probe. We have, therefore, the singular case of two forms of the bill arising in the same species as a result of or caus- ing a corresponding difference in habit.