This is the third time this drawing has appeared here but the first time I’ve been able to fully credit the artist. Walpurgisnacht appeared in issue 604 (April 26, 1917) of Austrian humour magazine Die Muskete. Dier was Austrian, and contributed to many issues of Die Muskete around this time, always credited as “Amadeus” hence the difficulty in tracing his identity. Most of the other magazine illustrations I’ve seen are a lot less memorable than this one; as I’ve said before, Walpurgisnacht could easily have been drawn in 1971. The erotic qualities of the drawing may be deliberate if the attribution of a pornographic series (see below) is accurate. I’ve not been able to find authoritative confirmation for this so don’t take my word for it.
Big thanks to Kuinesis for sending the solution to this mystery. The drawings above and below are also from Die Muskete, and via Kuinesis’s Tumblr, as is one of the bookplates.