The conditions of wing reduction (brachyptery) and loss of wings (aptery), and modifications thereof, are reviewed across all known families of Lepidoptera where this has been observed in either males or females, or both sexes. Brachyptery or aptery is known in 35 families of Lepidoptera, including families or species where a kind of brachyptery is only evident as extreme wing reduction of the hind wings. Examples from most families known to have brachyptery of some form are illustrated among 147 figures.
