A note with half the value of a semiquaver. One thirty-second of a semibreve. That is, a demisemiquaver is a thirty-second note.
                      ___                   ___
      |              /###\                 /###\
      |\            |#####|               |#####|
      | \           |\###/                |\###/
      |\ )          |                     |
      | \           |                     |
      |\ )          |                     |
      | \           |                     |
      |  )          |                     |
  ___ |             |                     |
 /###\|             |_____________________|
|#####|             |_____________________|
 \###/              |_____________________|
That's three tails.

Also known as a semidemiquaver.