Neoptera is a classification group that includes almost all the winged insects, specifically those that can flex their wings over their abdomens. This is in contrast with the more basal orders of winged insects (the "Paleoptera" assemblage), which are unable to flex their wings in this way.
ITIS lumps all neopteran orders together in this infraclass without subdivision; other authorities recognise several superorders within it. Almost universally accepted are the Exopterygota - hemimetabolous neopterans, in which the wings are already visible before the adult stage and no pupa or chrysalis stage occurs -, and the Endopterygota, the holometabolous insects in which the wings develop inside the body during the larval stage and only become external appendages during the pupa or chrysalis stage.
As of recently, there are several attempts to resolve the neopteran diversity further. While this appears to be less controversial than in the (apparently paraphyletic) "Palaeoptera", there are nonetheless lots of unresolved questions. For example, the hymenopterans, traditionally considered highly advanced due to their intricate social systems, seem to be far more basal among the Endopterygota, as suggested by their relatively plesiomorphic anatomy and molecular data. The exact position of the proposed Dictyoptera is also uncertain, namely whether they are better considered Exopterygota or basal neopterans.