Ento-parasite: one that feeds within the body of the host.
"Explanation of Terms Used in Entomology" by John. B. Smith
At last a long-drawn "Ha" from myself duetted (if I may coin the word) with "Y'r ento 'm, sir," from Guthrie.
"Lines in Pleasant Places" by William Senior
Even if you manage to get past Entos and into the Palace, we can have you extradited as a common criminal, for assaulting a Sanctioner.
"A Matter of Honor" by Ann Wilson