epimerum

from The Collaborative International Dictionary of English v.0.48

Epimeron \E*pim"e*ron\, n.; pl. {Epimera}. [NL., fr. Gr. 'epi`
   upon + ? a part.] (Zo["o]l.)
   (a) In crustaceans: The part of the side of a somite external
       to the basal joint of each appendage. See Illust. under
       {Crustacea}.
   (b) In insects: The lateral piece behind the episternum.
       [Written also {epimerum}.]
       [1913 Webster]