Endoparasite
A parasite living inside its host's body, as opposed to an ectoparasite. Birds are subject to a great deal of infestation by endoparasites, the main types being cestodes (tapeworms), nematode and thorny-headed worms, trematodes (flukes) and the tiny protozoans.From Peter Weaver's Birdwatcher's Dictionary
Copyright © 1981 by Peter Weaver