The authors describe and illustrate two hymenolepidid cestodes parasitising Himantopus melanurus (Aves) from Paraguay. Microsomacanthus kaulobatroni n. sp., 20–30 long × 0.6 mm wide, with 10 diorchoid hooks 33–38 µm long, three testes in a transverse row, short cirrus 20–28 µm long armed with very minute spines, a short vagina with a sphincter, and a multi-lobed ovary, with genital ducts similar to those of Hymenolepis himantopodis ( sensu Fuhrmann, 1906) but with rostellar hooks different from those of Taenia himantopodis Krabbe, 1869 sp. inq. Wardium neotropicale n. sp., 40-50 long x 0.9 mm wide, has campanulate proglottides, scolex with 10 aploparaksoid rostellar hooks 9 µm long, testes arranged in a triangle, a short cirrus pouch without a transverse retractor muscle, very short, unarmed cirrus, a short vagina with a sphincter (30–35 µm in diameter) but no retractor muscle, a multi-lobed ovary and a bipartite uterus. The shape of the hooks distinguishes this species from T. himantopodis Krabbe, 1869 and other aspects of its anatomy from other species of Wardium with hooks of a similar size. A single specimen of a third Hymenolepis (sensu lato) species (lacking the scolex) could not be identified.