Three related genera of Asian Amiseginae, Baeosega Krombein, Nipponosega Kurzenko & Lelej, and Okinawasega Terayama are revised. The male of N. yamanei Kurzenko & Lelej and the female of O. eguchii Terayama are newly described. The following new synonymies are proposed: Baeosega humida Krombein, 1984 = B. laticeps Krombein, 1984, syn. nov.; Nipponosega yamanei Kurzenko & Lelej, 1994 = N. kantoensis Nagase, 1995, syn. nov. A new species of Nipponosega, N. lineata sp. nov. is described based on a female from Thailand. A key to genera and species of Baeosega, Nipponosega and Okinawasega is given.