On the distribution of gregarines in oligochaetes

Abstract

Watson-Kamm (1916, 1922) has given complete lists of cephaline gregarine parasites from different classes of hosts, discovered up to 1920. She concluded that "except in rare instances a species is confined to a single host or to nearly related hosts, not being found in insects as far removed from each other as the Coleoptera and the Orthoptera." She belives there is an interesting parallelism between the complexity of the parasite and the group of hosts in which they are found. The simpler forms occurring in the Crustacea and Diplopodia, and the higher and more complex forms being found in various orders of Insecta. Many instances could be mentioned in which genera are found exclusively in a single order of insects.