Dear Erich,
The Drupa ricnus with the yellow markings that you have are
Drupa ricinus var. arachnoides Lamarck, 1816. I have a number of these
in my collection. Most typical ricinus have traces of yellow around the
aperture,
but arachnoides has a very distinctive ring of yellow-orange dashes
around the aperture.

Kind Regards,
James


Ohio Molluscan Studies
c/o James M. Cheshire
427 E. College St.
Granville, Ohio 43023
USA