The silky lacewings are distinguishable in their adult stage by their spectacularly patterned and pubescent wings, broad wing shape, dense venation, and the presence of a vena triplica (the apical fusion of three veins in the hindwing).
They were formerly placed in the superfamilyHemerobioidea, but do not seem to be closely related to these net-winged insects at all. Rather, might be closer to the Myrmeleontoidea which contain for example the antlions (Myrmeleontidae). In particular, the spoon-winged laceflies (Nemopteridae) seem to be very closely related to the silky lacewings. These had at one time been placed in a superfamilyNemopteroidea. The fossil family Osmylopsychopidae was - as indicated by their scientific name - initially believed to be intermediate between the Psychopsidae and the Osmylidae. But actually these similarities are due to plesiomorphies in the first case, and simply misperceived in the second; the osmylopsychopids are one of the basal lineages of the Myrmeleontoidea as traditionally defined. The Nemopteroidea were eventually abolished and its members included in the Myrmeleontoidea. But as the silky and spoon-winged lacewings together with the "butterfly" lacewings of the Kalligrammatidae do seem to form a quite distinct clade among the expanded Myrmeleontoidea, it appears well warranted to reinstate the Nemopteroidea for them.
The family currently includes five living genera in two subfamilies and a number of extinct genera with positions in the family that are uncertain. The following extinct genera are based on Peng et al. 2011:
^ abcPeng, Y.; Makarkin, V.N.; Wang, X.; Ren, D. (2011). "A new fossil silky lacewing genus (Neuroptera, Psychopsidae) from the Early Cretaceous Yixian Formation of China". ZooKeys130: 217–228. doi:10.3897/zookeys.130.1576.
^Grimaldi, D. and M. S. Engel. 2005. Evolution of Insects. Cambridge University Press, New York.
^Makarkin, V.; Archibald, S.B. (2014). "An unusual new fossil genus probably belonging to the Psychopsidae (Neuroptera) from the Eocene Okanagan Highlands, western North America". Zootaxa3838 (3): 385–391. doi:10.11646/zootaxa.3838.3.8.