Thelastoma krausi n. sp. is described based on specimens from the hindgut of Euryurus leachii (Gray, 1832) collected in central Ohio, U.S.A. Females of this species have the excretory pore located at the point of the esophageal bulb and have a longer tail than that of several other species. In comparison to species that also share these characters, no other species shares similar anatomical dimensions. In most similar species, the female esophageal length is longer than that of T. krausi n. sp. The female tail length is also longer than that of many similar species. The males of T. krausi n. sp. lack lateral alae and have an arrangement of papillae around the genital cone, including only a single postcloacal papilla, which varies from that of other described species.