Which apterygote groups have ectognathous mouthparts?

Within the context of the groups traditionally referred to as apterygotes, those that possess ectognathous mouthparts—meaning their mouthparts are exposed rather than retracted into the head—are classified under the class Insecta within the subclass Apterygota.1

These groups include:

• Order Archaeognatha: Commonly known as bristletails, these insects feature compound eyes, three ocelli, and a long median tail filament.1
• Order Zygentoma: This group includes silverfish, firebrats, and fishmoths.21
• Order Monura: An extinct group of primitive wingless insects.21

In contrast, other groups often associated with the term apterygote—specifically proturans, collembolans, and diplurans—are characterized by entognathous mouthparts, where the mouthparts are sunk below the surface of the head.13