The demon Halphas appears in the grimoires Book of Incantations, The Discoverie of Witchcraft, Pseudomonarchia Daemonum, and The Lesser Key of Solomon
From The Lesser Key of Solomon, Crowley/Mathers edition:
The Thirty-eighth Spirit is Halphas, or Malthus (or Malthas). He is a Great Earl, and appeareth in the form of a Stock-Dove. He speaketh with a hoarse Voice. His Office is to build up Towers, and to furnish them with Ammunition and Weapons, and to send Men-of-War to places appointed. He ruleth over 26 Legions of Spirits, and his Seal is this, etc.