This is Thrilling Mystery for July 1937, cover artist unrecorded. The ISFDB entry for this issue is here. I found this version of the cover in this Pinterest gallery put together by Raphael Desoto.
Follow-on: This was a post in error, but now that it has gone up I’m inclined to keep it where it is. I’ve done a minor change in renumbering it to “94x.”
A novelette of unimaginative blurb writers.