Beel-Zebub (Heb.). The disfigured Baal of the Temples. and more correctly Beel-Zebul. Beel-Zebub means -literally “god of flies” ; the derisory epithet used by the Jews, and the incorrect and confused rendering of the “god of the sacred scarabæi”, the divinities watching the mummies, and symbols of transformation, regeneration and immortality. Beel-Zeboul means properly the “ God of the Dwelling:’ and is spoken of in this sense in Matthew x. 25. As Apollo, originally not a Greek but a Phenician god, was the healing god, Paiàn, or physician, as well as the god of oracles, he became gradually transformed as such into the “Lord of Dwelling”, a household deity, and thus was called Beel-Zeboul. He was also, in a sense, a psychopompic god, taking care of the souls as did Anubis. Beelzebub was always the oracle god, and was only confused and identified with Apollo latter on.
Source: H.P.Blavatsky - The Theosophical Glossary