Wingless insects belong to
Apterygota includes primitively wingless hexapods that never evolved wings throughout their lineage, comprising orders Archaeognatha jumping bristletails and Zygentoma silverfish and firebrats. Characteristics include ametabolous development without distinct nymphal change except size, monocondylic mandibles with single articulation, abdominal styli, continuous molting even after sexual maturity and lack of flight musculature. Pterygota comprise winged insects and secondarily wingless groups like fleas and lice that secondarily lost wings. Apterygote condition reflects ancestral hexapod state
Ref: Brusca & Brusca, Invertebrates, 3rd ed., Apterygota; NCERT Class 11, Chapter 4, Insect Classification
