E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Devil and his Dam (The).
Either the Devil and his mother, or the Devil and his wife. Numerous quotations may be adduced in support of either of these interpretations. Shakespeare uses the phrase six times, and in King John (ii. 1) dam evidently means mother; thus Constance says that her son Arthur is as like his father as the Devil is like his dam (mother); and in Titus Androncus Tamora is called the dam of a black child. We also read of the Devils daughter and the Devils son.
In many mythologies the Devil is supposed to be an animal: Thus in Cazottes Diable Amoureux he is a camel; the Irish and others call him a black cat; the Jews speak of him as a dragon (which idea is carried out in our George and the Dragon); the Santons of Japan call him a species of fox; others say he is a goat; and Dante associates him with dragons, swine, and dogs. In all which cases dam for mother is not inappropriate.
On the other hand, dam for leman or wife has good support. We are told that Lilith was the wife of Adam, but was such a vixen that Adam could not live with her, and she became the Devils dam. We also read that Belphegor came to earth to seek him out a dam.
As women when they go wrong are for the most part worse than the other sex, the phrase at the head of this article means the Devil and something worse.