Halipegus eccentricus is a monoecious, digenea parasitic trematode commonly found in true frogs in North America. It was first described in 1939 . H. eccentricus is mainly found in the Eustachian tubes of a variety of frog species, its definitive host, although its life cycle involves other hosts, as is common for trematodes. Earlier research proposed that its life cycle involved two other species of hosts (ostracods and snails); however, subsequent research has revealed that the nymph form of the damselfly is also involved .