We redescribe the monotypic spider genus Cepheia and provide detailed morphological information on its type species, Cepheia longiseta. We provide the first exhaustive diagnosis for the genus, including for the first time detailed information about its external morphology as well as its tracheal system. Some morphological features previously proposed as synapomorphies for the Synaphridae are also present in Cepheia, which corroborates some of the diagnostic characters of the family. We also propose new synapomorphies for Synaphridae.