The Collaborative International Dictionary of English v.0.48:

Demonocracy \De`mon*oc"ra*cy\, n. [Gr. dai`mwn demon + kra`tos
   strength: cf. F. d['e]monocratie.]
   The power or government of demons.
   [1913 Webster]

         A demonocracy of unclean spirits.        --H. Taylor.
   [1913 Webster]