Hydrachna similans Marshall, 1928

Material examined. 1/0/0, rice field, Ubon Ratchathani Province, 24-x-2010, 15° 32.347ʹ N, 104° 26.052ʹ E; 0/1/0, pond next to Science Faculty building, Mahasarakham University, Maha Sarakham province, 16° 14.868ʹ N, 103° 15.014ʹ E, 2-xi-2016.

Remarks. A number of closely related specimens were described from the Oriental region. Here we follow Lundblad (1969), for the discussion see there. Imamura (1964) reported the species from Thailand under the name of H. kloomi Imamura, 1964 .