The demon Malphas appears in the grimoires Book of Incantations, The Discoverie of Witchcraft, The Book of the Office of Spirits, Pseudomonarchia Daemonum, The Lesser Key of Solomon, and Dictionnaire Infernal
From The Lesser Key of Solomon, Crowley/Mathers edition:
Malphas
The Thirty-ninth Spirit is Malphas. He appeareth at first like a Crow, but after he will put on Human Shape at the request of the Exorcist, and speak with a hoarse Voice. He is a Mighty President and Powerful. He can build Houses and High Towers, and can bring to thy Knowledge Enemies' Desires and Thoughts, and that which they have done. He giveth good Familiars. If thou makest a Sacrifice unto him he will receive it kindly and willingly, but he will deceive him that doth it. He governeth 40 Legions of Spirits, and his Seal is this, etc.
Timeline of related events
1500
1700
1800
1810
1818
Publication of Dictionnaire Infernal (lists this demon)