My original tumblr post was here. This pulp cover was first posted on tumblr by UDHCMH who added this commentary:

Weird Tales, July 1933, featuring the Seabury Quinn story “The Hand of Glory.”

Illuminati burglars use a “hand of glory” to steal a magical artifact from an archaeologist. The thieves use the object’s weird powers to lure an innocent young beauty into the clutches of a cult that worships a hermaphroditic demon from ancient times. Only paranormal detective Jules de Grandin and the unflappable Dr. Trowbridge can save the young woman and deliver cult-infested Harrisonville NJ from its latest peril.

The artist isn’t specified, but by the style I would guess Margaret Brundage.