Studies on the Life History and Development of Macracanthorhynchus ingens Meyer, 1933, with a Redescription of the Adult Worm

Abstract

The life history and development of M. ingens* had been detd. by exptl. infections and complete descriptions of the developmental stages given. The intermediate hosts so far detd. are grubs of the scarabaeid beetles Phyllophaga crinita, P. hirtiventris, and Ligyrus sp. The period of development at temps. of 20[degree]-22[degree]C varies from 60 to 70 days. Penetration of the gut wall of the intermediate host occurs 30-35 days after infection. The pre-acanthella develops 50-55 days, and the infective acanthella 60-70 days after infection. In one expt. a frog was shown to be a possible transport host. It does not seem probable that the transport host is necessary for the completion of the cycle, but no exptl. infections of the definite host were attempted. Some comparisons are drawn between the development of M. hirudin-aceus and M. ingens.