Dicondylia

Pterygota ( ) is a subclass of insects that includes all winged insects and groups which lost them secondarily.

Zygentoma are an order in the class Insecta, and consist of about 550 known species. The Zygentoma include the silverfishes or fishmoths, and the firebrats. A conspicuous feature of the order are the three long caudal filaments. The two lateral filaments are cerci, and the medial one is an epiproct or appendix dorsalis. In this they resemble the Archaeognatha, although the cerci of Zygentoma, unlike in the latter order, are nearly as long as the epiproct.

Dicondylia is a taxonomic group (taxon) that includes all insects except the jumping bristletails (Archaeognatha). Dicondylia species have a mandible attached with two hinges to the head capsule (dicondyl), in contrast to a hypothetical ancestral mandible with a single ball joint (monocondyl); the members of Archaeognatha do in fact have dicondylic mandibles, though they are not identical to the structure seen in "true" dicondylic insects.