The larval stages of a tapeworm, including the metamorphosis of the oncosphere to the first evidence of sexuality in the adult worm, differentiation of the scolex, and beginning of proglottid formation; it includes the procercoid and plerocercoid stages of pseudophyllid cestodes, and the cysticercus, cysticercoid, coenurus, and hydatid stages of cyclophyllidean cestodes.
