Source : Webster's Revised Unabridged Dictionary (1913)

Endoparasite \En`do*par"a*site\, n. [Endo- + parasite.]
   (Zo["o]l.)
   Any parasite which lives in the internal organs of an animal,
   as the tapeworms, Trichina, etc.; -- opposed to ectoparasite.
   See {Entozo["o]n}. -- {En`do*par`a*sit"ic}, a.

Source : WordNet®

endoparasitic
     adj : of or relating to parasites that live in the internal organs
           of animals