The Siphloplecton jaegeri species group is established here for three extinct species, namely for the earlier described Siphloplecton jaegeri Demoulin, 1968, and for two new species from Eocene Baltic amber, Siphloplecton landolti sp. nov. and Siphloplecton studemannae sp. nov. Based on the well-preserved specimens of these species, a diagnosis is provided for the newly established species group. Representatives of the S. jaegeri species group are characterized by the presence of large, medially contiguous eyes, stout pointed setae along the outer margin of the foretibia, three intercalaries in the cubital field of the forewing, and elongated penis lobes, which are apically triangular or rounded, medially contiguous, and with a V-shaped cleft apically. Further new specimens of the S. jaegeri species group are documented that cannot be attributed to species level due to their poor preservation. Finally, a key to male adults of fossil species of Siphloplecton is given.