Missing Method in CaptchaController

Error: The action captcha.php is not defined in controller CaptchaController

Error: Create CaptchaController::captcha.php() in file: app/controllers/captcha_controller.php.

<?php
class CaptchaController extends AppController {

	var $name = 'Captcha';


	function captcha.php() {

	}

}
?>

Notice: If you want to customize this error message, create app/views/errors/missing_action.ctp.