Trephionus babai, is a species of beetle belonging to the family Carabidae. It is endemic to Japan.[1]
Body length of male is about 9.3 mm, whereas female is 9.8–10.3 mm. Dorsal surface black. Endophallus long oval. No hind wings. Dorso-apical lobe narrowly swollen. Apex of aedeagus rounded.