Hydrocolus is a genus of beetles in the family Dytiscidae, containing the following species:
- Hydrocolus deflatus <small>(Fall, 1923)</small>
- Hydrocolus filiolus <small>(Fall, 1923)</small>
- Hydrocolus heggiensis <small>Ciegler, 2001</small>
- Hydrocolus oblitoides <small>Roughley & Larson, 2000</small>
- Hydrocolus oblitus <small>(Aubé, 1838)</small>
- Hydrocolus paugus <small>(Fall, 1923)</small>
- Hydrocolus persimilis <small>(Crotch, 1873)</small>
- Hydrocolus rubyae <small>(Larson, 1975)</small>
- Hydrocolus rufiplanulus <small>(Fall, 1923)</small>
- Hydrocolus rupinus <small>Roughley & Larson, 2000</small>
- Hydrocolus sahlbergi <small>Nilsson, 2001</small>
- Hydrocolus stagnalis <small>(Gemminger & Harold, 1868)</small>
References