The
Entognatha are a
class of wingless (ametabolous)
arthropods, which, together with the
insects, makes up the subphylum
Hexapoda. Their
mouthparts are entognathous, meaning that they are retracted within the head. Entognatha are
apterous, meaning that they lack
wings. The class contains three
orders: Collembola (
springtails),
Diplura and
Protura. These three groups were historically united with the order
Thysanura to form the class
Apterygota, but it has since been recognized that the hexapodous condition of these animals has evolved independently from that of insects, and independently
within each order. The orders may not be closely related, in which case Entognatha would be a
polyphyletic group.
