Abstract
In the digestive tube of 200 specimens of aquatic arthropods belonging to orders of the Classes of Crustacea and Insects and taken from two different biotopes (Lake Trasimene and the River Tiber) the following species of eugregarines were isolated (those marked with an asterisk are now reported for Italy for the first time): Rotundula gammari Goodrich (*); Eliterocystis ephemerae Franzius (*); Actinocephalus sieboldi Kölliker (*); Pileocephalus nemourae (Foerster, 1938) Stein (*); Stylocystis sp. (*); Asterophora tiaroides Baudoin, Asterophora sp., Ancyrophora sp. 2 Baudoin; Sphaerocystis sp. (*).