Topic summary
apterous

Extracted from the Wikipedia article Aptery.
Apterous is an adjective that means that the insect or organism is wingless and usually refers to a particular form of an insect that may have wings, or a wingless species in a group that typically has wings, e.g. many Orthoptera (grasshoppers and allies) and Hymenoptera (wasps). In some groups, one sex may be apterous while the other is winged, e.g. Mutillidae (velvet ants) and Coccoidea (scale insects). In other cases, a particular form of an insect (but not all individuals) will be apterous, e.g. some Tetrigidae (pygmy grasshoppers). Wingless animals which belong to or are phylogenetic descendants of winged taxa are said to be secondarily apterous. Five percent of extant Pterygota are believed to be secondarily apterous, including entire orders, such as fleas and Notoptera.