New genus and new species Gedanoborus kerneggeri from Eocene Baltic amber is described and illustrated. Its systematic position is discussed. The new genus together with fossil Taimyborus Lukashevich, 1999 form sister groups of extant subfamilies Chaoborinae + Eucorethrinae. Tertiary genus Eochaoborites Hong, 2002 is excluded from the Chaoboridae and transferred to Psychodidae. A key for the identification of phantom midges from Baltic amber is provided.