Abstract
Additional information on the morphology of Mediorhynchus grandis is provided in the form of a redescription. The host list is extended by the addition of Molothrus ater ater, Passerherbulus caudacutus and Turdus migratorius. The life history and development as determined by experimentally infected grasshoppers is presented in detail. Experimental life history studies were carried out in Chortophaga viridifasciatus australior, Orphullea pelidna, Arphia luteola and Schistocerca americana. Experimental results indicate that crickets, Gryllus sp. and chrysomelid beetles, Gastroidea cyanea, are potential intermediate hosts. Experimental infections in two final hosts, a grackle and a meadowlark, were accomplished. The possible use of certain characters of the acanthor in the determination of taxonomic and phylo-genetic relationships is discussed.