We describe a new species of Ditha Chamberlin 1929, from Okinawa, Japan, as Ditha okinawensis n. sp. This species differs from other Ditha species in the number and position of setae at the cheliceral hand, carapace, rallum and male sternite II. Ditha ogasawarensis Sato 1981 is redescribed based on the re-examination of the type specimens and is transferred from the subgenus Ditha to Paraditha.
