Exoporia are a group of primitive Lepidoptera comprising the superfamilies Mnesarchaeoidea and Hepialoidea (Kristensen, 1999; Nielsen et al., 2000). Exoporia is a natural group or clade which is the sister group of the lepidopteran infraorderHeteroneura. They are characterised by the unique female reproductive system which has an external groove between the "ostium bursae" and the ovipore by which the sperm is transferred to the egg rather than having the mating and egg-laying parts of the abdomen with a common opening (cloaca) as in other non-ditrysianmoths, or with separate openings linked internally by a "ductus seminalis" as in Ditrysia (Nielsen et al., 2000). See Kristensen (1999: 57) for other exoporian characteristics.
Kristensen, N.P., (1999) . The non-Glossatan Moths. Ch. 4, pp. 41–62 in Kristensen, N.P. (Ed.). Lepidoptera, Moths and Butterflies. Volume 1: Evolution, Systematics, and Biogeography. Handbook of Zoology. A Natural History of the phyla of the Animal Kingdom. Band / Volume IV Arthropoda: Insecta Teilband / Part 35: 491 pp. Walter de Gruyter, Berlin, New York.
Nielsen, E.S., Robinson, G.S. and Wagner, D.L. 2000. Ghost-moths of the world: a global inventory and bibliography of the Exoporia (Mnesarchaeoidea and Hepialoidea) (Lepidoptera) Journal of Natural History, 34(6): 823-878.Abstract