1. Species Haplotaxis aedeochaeta Brinkhurst & Marchese, 1987
2. Species Haplotaxis ascaridoides Michaelsen, 1905
3. Species Haplotaxis dubius (Hrabĕ, 1931)
4. Species Haplotaxis gastrochaetus Yamaguchi, 1953
5. Species Haplotaxis gordioides (Hartmann in Oken, 1819)
6. Species Haplotaxis heterogyne Benham, 1903
7. Species Haplotaxis vermivorus (Michaelsen, 1932)
8. Species Haplotaxis villiersi Omodeo, 1987
9. Species Haplotaxis africanus (Michaelsen, 1905) accepted as Pelodrilus africanus Michaelsen, 1905 (unaccepted > superseded combination, Following a taxonomic analysis of the Haplotaxidae, Brinkhurst (1988) re-established the species in the genus Pelodrilus, although the species was considered incertae sedis.)
10. Species Haplotaxis attemsi (Michaelsen, 1903) accepted as Helodrilus (Dendrobaena) attemsi Michaelsen, 1903 accepted as Dendrobaena attemsi (Michaelsen, 1903) (lapsus)
11. Species Haplotaxis brinkhursti Cook, 1975 accepted as Metataxis brinkhursti (Cook, 1975)
12. Species Haplotaxis bureschi (Michaelsen, 1925) accepted as Delaya bureschi (Michaelsen, 1925)
13. Species Haplotaxis cantabronensis Delay, 1973 accepted as Delaya cantabronensis (Delay, 1973)
14. Species Haplotaxis carnivorus Omodeo (in litt.): Omodeo, 1958 accepted as Haplotaxis villiersi Omodeo, 1987 (name in litteris not proposed for the purposes of nomenclature, not available under Article 8.3 ICZN)
15. Species Haplotaxis corbarensis Delay, 1972 accepted as Delaya corbarensis (Delay, 1972)
16. Species Haplotaxis denticulatus (Cekanovskaya, 1959) accepted as Adenodrilus denticulatus Čekanovskaja, 1959
17. Species Haplotaxis forbesi Smith, 1918 accepted as Haplotaxis gordioides (Hartmann in Oken, 1819) (unaccepted > junior subjective synonym)
18. Species Haplotaxis glandularis (Yamaguchi, 1953) accepted as Heterochaetella glandularis Yamaguchi, 1953
19. Species Haplotaxis hologynus (Michaelsen, 1907) accepted as Hologynus hologynus (Michaelsen, 1907)
20. Species Haplotaxis ichthyophagus Gates, 1971 accepted as Haplotaxis ichthyophagous Gates, 1971 (lapsus)
21. Species Haplotaxis ignatovi (Michaelsen, 1903) accepted as Pelodrilus ignatovi Michaelsen, 1903
22. Species Haplotaxis leruthi (Hrabĕ, 1958) accepted as Delaya leruthi (Hrabĕ, 1958)
23. Species Haplotaxis lichtensteinii (Schlotthauber, 1860) accepted as Haplotaxis gordioides (Hartmann in Oken, 1819) (unaccepted > junior subjective synonym)
24. Species Haplotaxis menkeana Hoffmeister, 1843 accepted as Haplotaxis gordioides (Hartmann in Oken, 1819) (unaccepted > junior subjective synonym)
25. Species Haplotaxis menkei (Schlotthauber, 1860) accepted as Haplotaxis gordioides (Hartmann in Oken, 1819)
26. Species Haplotaxis navarrensis Delay, 1973 accepted as Delaya navarrensis (Delay, 1973)
27. Species Haplotaxis ornamentus Brinkhurst & Fulton, 1980 accepted as Hologynus ornamentus (Brinkhurst & Fulton, 1980) (unaccepted > superseded combination)
28. Species Haplotaxis smithii (Beddard, 1888) accepted as Alphadrilus smithii (Beddard, 1888)
29. Species Haplotaxis violaceus (Beddard, 1891) accepted as Pelodrilus violaceus Beddard, 1891
30. Species Haplotaxis acystis Michaelsen, 1903 (uncertain > unassessed)
31. Species Haplotaxis bretscheri Cognetti, 1903 (uncertain > unassessed)
32. Species Haplotaxis emissarius (Forbes, 1890) (uncertain > taxon inquirendum)
33. Species Haplotaxis ichthyophagous Gates, 1971 (uncertain > taxon inquirendum)
34. Species Haplotaxis intermedia Pierantoni, 1904 (uncertain > unassessed)
35. Species Haplotaxis intermedius Michaelsen, 1903 (uncertain > unassessed)

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