1. Species Tachidius discipes Giesbrecht, 1881
2. Subgenus Tachidius (Neotachidius) Shen & Tai, 1963 accepted as Neotachidius Shen & Tai, 1963 (upgraded to genus level by Huys et al. (2005))
   1. Species Tachidius (Neotachidius) triangularis Shen & Tai, 1963
3. Subgenus Tachidius (Tachidius) Lilljeborg, 1853 accepted as Tachidius Lilljeborg, 1853
   1. Species Tachidius (Tachidius) discipes Giesbrecht, 1881
4. Species Tachidius abrau Krichagin, 1877 accepted as Ectinosoma abrau (Krichagin, 1877) accepted as Halectinosoma abrau (Krichagin, 1877)
5. Species Tachidius acutifrons (Dana, 1847) accepted as Euterpe gracilis Claus, 1863 accepted as Euterpina gracilis (Claus, 1863) accepted as Euterpina acutifrons (Dana, 1848)
6. Species Tachidius arcticus Olofsson, 1917 accepted as Tachidius discipes Giesbrecht, 1881 (unaccepted > junior subjective synonym)
7. Species Tachidius berberus Monard, 1935 accepted as Microarthridion berberum (Monard, 1935)
8. Species Tachidius brevicornis Lilljeborg, 1853 accepted as Tachidius discipes Giesbrecht, 1881 (unaccepted > misapplication)
9. Species Tachidius convergens Labbé, 1927 accepted as Tachidius discipes Giesbrecht, 1881 (unaccepted > junior subjective synonym)
10. Species Tachidius crassicornis Scott T., 1892 accepted as Microarthridion littorale (Poppe, 1881) (synonym according to Lang (1948))
11. Species Tachidius elongatus (Labbé, 1926) accepted as Euterpina acutifrons (Dana, 1848) (unaccepted > junior subjective synonym)
12. Species Tachidius hydrobiologicus Oliveira, 1945 accepted as Euterpina acutifrons (Dana, 1848) (unaccepted > junior subjective synonym)
13. Species Tachidius incisipes Klie, 1913 accepted as Geeopsis incisipes (Klie, 1913)
14. Species Tachidius laurenticus Nicholls, 1939 accepted as Microarthridion laurenticum (Nicholls, 1939)
15. Species Tachidius littoralis Poppe, 1881 accepted as Microarthridion littorale (Poppe, 1881)
16. Species Tachidius longicornis Olofsson, 1917 accepted as Geeopsis longicornis (Olofsson, 1917)
17. Species Tachidius minutus Claus, 1866 accepted as Ectinosoma melaniceps Boeck, 1865 (unaccepted > junior subjective synonym)
18. Species Tachidius pygmaeus Krichagin, 1873 accepted as Ectinosoma melaniceps Boeck, 1865 (unaccepted > junior subjective synonym)
19. Species Tachidius reductus Monard, 1935 accepted as Microarthridion reductum (Monard, 1935)
20. Species Tachidius rotus (Labbé, 1926) accepted as Tachidius discipes Giesbrecht, 1881 (unaccepted > junior subjective synonym)
21. Species Tachidius spitzbergensis Olofsson, 1917 accepted as Tachidius discipes Giesbrecht, 1881 (unaccepted > junior subjective synonym)
22. Species Tachidius triangularis Shen & Tai, 1963 accepted as Neotachidius triangularis (Shen & Tai, 1963)
23. Species Tachidius vicinospinalis Shen & Tai, 1964 accepted as Sinotachidius vicinospinalis (Shen & Tai, 1964) (synonym)
24. Species Tachidius fonticola Chambers, 1881 (uncertain > taxon inquirendum)

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