The fossil aphid Schizoneurites obliquus n.sp. from the Copenhagen collection of Baltic amber insects is described; the presence of one oblique vein in the hind wing separates it from the six previously described species of this genus, Schizoneurites Cockerell, 1915, of which Antiquaphis Heie, 1967, and Elektraphis Steffan, 1968, are synonyms. A new diagnosis of the genus and a key to the species are given. In specimens of S. robustus (Heie, 1967) and S. fossilis (Heie, 1967) occurring among the other Baltic amber insects recently acquired by the Zoological Museum of Copenhagen, structures resembling the rhinaria in Adelges Vallot are visible on the three terminal antennal segments, confirming the view held by Steffan (1968) that the group belongs in the Aphidina ovipara. The rhinaria, which have not been seen before, also shows that Schizoneurites, the only genus within the family Elektraphididae Steffan, 1968, together with the Adelgidae, forms a group, of which the Phylloxeridae is the sister group. The synapomorphies of the Elektraphididae and Phylloxeridae are explained as results of convergent or parallel evolution.