1. Tarsal formul 4-5-5; eyes acutely angulate ventrally; antenna inserted very near eye; distributed in the Oriental Region; living in fresh water habitat. ...........Acontosceles Champion
-.Tarsal formula 4-4-4 or 4-5-5; eyes evenly arcuate or broadly angulate ventrally; antenna inserted near mandibles and distant from eye. .........2
2. Antennae 7-segmented; distributed in Central America; living in rocky seashore. ........Martinius Spilman
-. Antennae 11-segmented. ...........3
3. distributed in Central America and the Oriental Region; living in rocky seashore.......... Mexico Spilman / Babalimnichus Sato
-. distributed in the Oriental Region; living in fresh watr havitat (i.e. river andstream) ........... Pseudeucinetus Heller