Apterygota
The classification of the Apterygota changed over time. By the mid 20th century, the subclass included four orders (Collembola, Protura, Diplura, and Thysanura). With the advent of a more rigorous cladistic methodology, the subclass turned out to be paraphyletic. The first three groups formed a monophyletic group, the Entognatha. The Thysanura is more closely related to winged insects. thus rendering even the amyocerate apterygotes paraphyletic.