Acarus

from WordNet (r) 3.0 (2006)

acarus
    n 1: any of several mites of the order Acarina [syn: {acarus},
         {genus Acarus}]

from The Collaborative International Dictionary of English v.0.48

Acarus \Ac"a*rus\, n.; pl. {Acari}. [NL., from Gr. ? the cheese
   mite, tick.] (Zool.)
   A genus including many species of small mites.
   [1913 Webster]