The Bogey-man was a devil derived from the Slavic¬†bog, “god.” English cognates were bugabow, bugaboo, bugbear and boggle-bo which used to designate the pagan image carried in a procession to the May Day games. (see¬†Maypole) “Humbug” came from the Norse¬†hum, “night,” plus¬†bog¬†or bogey, i. e., a night spirit. The word “bug,” from the Welsh¬†bwg, “spirit,” was applied to insects because of the old belief that insects were souls in search of rebirth. A¬†mantis¬†was a soul of the seer or wizard. A butterfly was¬†Psyche, or a Female Soul.

Other derivations of¬†bog¬†were Scotish¬†bogle, Yorkshire¬†boggart, English Pug, Pouke and Puck; Icelandic Puki; the¬†Puk¬†of Friesland; the German Putz or Butz; Irisk Pooka and Welsh¬†Pwcca; Danish Spoge and Swedish Spoka with theirEnglish offshoot of “spook.” The old English¬†puca, a fairy, was applied to the old gods of Beltain. So Puck was the same as the witches‚Äô god Robin.¬†A.G.H.

Source: 56.