Rheinhart Kleiner, with a New York address of 444 Evergreen Av, Brooklyn, in the mainstream Motion Picture magazine for May 1915…
This is an appearance three months earlier than the commonly cited “Piper for September 1915″ for this poem. Lovecraft replied to “To Mary…” with “To Charlie of the Comics” (Providence Amateur, February 1916) which started a sort of poetic jousting between the two.
Excellent discovery!