Prosorhynchoides fabulus n. sp. (Trematoda: Bucephalidae) is described from the intestine of white bass Morone chrysops (Moronidae) collected from the Neches River in the Big Thicket National Preserve in Texas, U.S.A. The new species is characterized by a relatively large cirrus sac extending anteriorly to the level of the ovary and cecum, a mouth nearly exactly midbody, obliquely arranged testes, a serpentine excretory bladder limited to the hindbody, and small size (<500 μm). The extent of the cirrus sac distinguishes P. fabulus n. sp. from most other species in the genus in North America. The new species displays similarities to Prosorhynchoides carvajali, Prosorhynchoides labiatus, and Prosorhynchoides megacirrus in the extent of the cirrus sac but differs from these species in combinations of the location of the vitellaria, position of the pharynx and mouth, extent of the excretory bladder, arrangement and position of the gonads, and body size.