Clinical material is presented leading to a discussion of beating fantasies which varies from Freud's model. Analysis shows that the fantasied role girls assign to mother as the punisher in the oedipal drama is equivalent to the fantasied role boys ascribe to father as castrator. For both sexes, castration anxiety spurs the internalization of parental prohibitions, the repression of oedipal wishes, and the subsequent structuralization of the superego. Mother establishes the "oedipal law" for the girl analogously to father's doing the same for the boy. The role that such fantasies play in the formation of the female superego is examined.