• Aartsenia arctica (Dall & Bartsch, 1909): ectoparasitic
• Aartsenia candida (Møller, 1842): ectoparasitic
• Aartsenia japonica (A. Adams, 1860): ectoparasitic
• Aartsenia martensi (Dall & Bartsch, 1906): ectoparasitic
• Aartsenia pupiformis (P. P. Carpenter, 1865): ectoparasitic
• Aartsenia sagamiensis Kuroda & T. Habe, 1971: ectoparasitic
• Aartsenia sasagensis (Nomura, 1939) †: ectoparasitic
• Aartsenia sikisimana (Nomura, 1939) †: ectoparasitic
• Abasia inflata Cressey & Cressey, 1979: ectoparasitic
• Abasia pillaii Cressey & Cressey, 1979: ectoparasitic
• Abasia platyrostris Pillai, 1963: ectoparasitic
• Abasia pseudorostris Wilson C.B., 1908: ectoparasitic
• Abasia pusilla Cressey & Cressey, 1979: ectoparasitic
• Abasia tripartita (Shiino, 1955): ectoparasitic
• Abathymermis acuticauda Rubzov, 1974: endoparasitic
• Abathymermis adventitia Rubzov & Kokordyak, 1973: endoparasitic
• Abathymermis arenaria (Coman, 1961) Rubzov, 1971: endoparasitic
• Abathymermis bissacea Rubzov, 1973: endoparasitic
• Abathymermis bissoidea Rubzov, 1972: endoparasitic
• Abathymermis brevicauda (Rubzov, 1972): endoparasitic
• Abathymermis fiseri Johnson & Kleve, 1995: endoparasitic
• Abathymermis ivaschkini Gafurov, 1980: endoparasitic
• Abathymermis microamphidis Rubzov, 1972: endoparasitic
• Abathymermis oesophaga Gafurov & An, 1989: endoparasitic
• Abathymermis ovtschinnikovi Ipatjeva & Pimenova, 1980: endoparasitic
• Abathymermis oxycerca (Steiner, 1929): endoparasitic
• Abathymermis parvula Rubzov, 1976: endoparasitic
• Abathymermis shocki Johnson & Kleve, 1995: endoparasitic
• Abathymermis tenuicauda (Rubzov, 1967): endoparasitic
• Abbreviata (Abbreviata) abbreviata (Rudolphi, 1819): parasitic
• Abbreviata (Abbreviata) kazachstanica Markov & Paraskiv, 1956: endoparasitic
• Abbreviata (Abbreviata) turkomanica Andrushko & Markov, 1956: parasitic
• Abbreviata baltazardi Chabaud, 1953: endoparasitic
• Abelspora portucalensis Azevedo, 1987: parasitic
• Abergasilus amplexus Hewitt, 1978: ectoparasitic
• Aberrapex arrhynchum (Brooks, Mayes & Thorson, 1981) Jensen, 2001: endoparasitic
• Aberrapex catarinensis Quadros, 2024: endoparasitic
• Aberrapex ludmilae Menoret, Mutti & Ivanov, 2017: endoparasitic
• Aberrapex manjajiae Jensen, 2006: endoparasitic
• Aberrapex panamensis Quadros, 2024: endoparasitic
• Aberrapex sanmartini Menoret, Mutti & Ivanov, 2017: endoparasitic
• Aberrapex senticosus Jensen, 2001: endoparasitic
• Aberrapex vitalemuttiorum Menoret, Mutti & Ivanov, 2017: endoparasitic
• Aberrapex weipaensis Koch, Jensen & Caira, 2012: endoparasitic
• Abirovulva insolita Hunt, 2002: parasitic
• Abortipedia indica Unnithan, 1962: ectoparasitic
• Abothrium gadi Van Beneden, 1870: parasitic
• Abscondicola humesi Fiers, 1990: ectoparasitic
• Absonifibula bychowskyi Lawler & Overstreet, 1976: ectoparasitic
• Absonifibula estuarina Santos & Timi, 2009: ectoparasitic
• Abuladzugnia gutterae (Ortlepp, 1963) Spasskii, 1973: endoparasitic
• Abyssoaclis alagoensis J. Barros, Mello, F. Barros, S. Lima, Santos, Cabral & Padovan, 2003: ectoparasitic
• Abyssopedunculus brevis (Andres & Overstreet, 2013) Martin, Huston, Cutmore & Cribb, 2019: endoparasitic
• Abyssopontius altus Stock, 1985: ectoparasitic
• Abyssotaurus vermiambatus Brenke, Fanenbruck & George, 2018: Parasitic
• Acaenodera nautili Bray & Justine, 2011: endoparasitic
• Acaenodera placophora Manter & Pritchard, 1960: endoparasitic
• Acaenodera spinosior Etchegoin, Lanfranchi, Cremonte & Timi, 2006: endoparasitic
• Acaenomolgus gottoi Stock, 1995: ectoparasitic
• Acaenomolgus protulae (Stock, 1959): ectoparasitic
• Acaenomolgus serpulae (Stock, 1960): ectoparasitic
• Acanthatrium aegyptiacus Saoud & Ramadan, 1980: endoparasitic
• Acanthatrium alicatai Macy, 1940: endoparasitic
• Acanthatrium amphidymum Cheng, 1957: endoparasitic
• Acanthatrium anaplocami Etges, 1960: endoparasitic
• Acanthatrium assiuti El-Naffar, Omran & Mandour, 1978: endoparasitic
• Acanthatrium atriopapillatum Capron, Deblock & Brygoo, 1961: endoparasitic
• Acanthatrium beuschleini Cheng, 1959: endoparasitic
• Acanthatrium bisutum Groschaft & Tenora, 1971: endoparasitic
• Acanthatrium cahirinus Saoud & Ramadan, 1980: endoparasitic
• Acanthatrium celebesi Khotenovsky, 1974: endoparasitic
• Acanthatrium chinensis Sun, 1988: endoparasitic
• Acanthatrium chosenicum (Ogata, 1941) Sogandares-Bernal, 1956: endoparasitic
• Acanthatrium copaccinii Khotenovsky, 1974: endoparasitic
• Acanthatrium eptesici Alicata, 1932: endoparasitic
• Acanthatrium eurytremum (Ogata, 1942) Dubois, 1961: endoparasitic
• Acanthatrium fugleri Marshall & Miller, 1979: endoparasitic
• Acanthatrium hitaensis Koga, 1953: endoparasitic
• Acanthatrium houini Richard, 1966: endoparasitic
• Acanthatrium japonicum (Yamaguti, 1939) Skarbilovich, 1948: endoparasitic
• Acanthatrium jonesi Sogandares-Bernal, 1956: endoparasitic
• Acanthatrium lageniforme Ogata, 1945: endoparasitic
• Acanthatrium lunatum Williams, 1960: endoparasitic
• Acanthatrium macyi Sogandares-Bernal, 1956: endoparasitic
• Acanthatrium microcanthum Macy, 1940: endoparasitic
• Acanthatrium molossidis Martin, 1934: endoparasitic
• Acanthatrium mukooyamai Kifune & Sawada, 1989: endoparasitic
• Acanthatrium nycteridis Faust, 1919: endoparasitic
• Acanthatrium oligacanthum Cheng, 1957: endoparasitic
• Acanthatrium oregonense Macy, 1939: endoparasitic
• Acanthatrium ovatum Yamaguti, 1939: endoparasitic
• Acanthatrium papilligerum Kifune & Sawada, 1989: endoparasitic
• Acanthatrium pipistrelli Macy, 1940: endoparasitic
• Acanthatrium rotundum Asada & Watanabe in Watanabe, 1959: endoparasitic
• Acanthatrium sogandaresi Coil & Kuntz, 1958: endoparasitic
• Acanthatrium sphaerula (Looss, 1896) Travassos, 1921: endoparasitic
• Acanthatrium sungi Matskasi, 1973: endoparasitic
• Acanthatrium taiwanense Fischthal & Kuntz, 1975: endoparasitic
• Acanthatrium taiwanense Kifune & Sawada, 1984: endoparasitic
• Acanthatrium tatrense Zdzitowiecki, 1967: endoparasitic