Entognatha

Entognatha
	Proturan specimen (Acerentomon sp.)
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Clade:	Pancrustacea
Clade:	Allotriocarida
Subphylum:	Hexapoda
Class:	Entognatha
Groups included
	Collembola (springtails); Diplura (two-pronged bristletails); Protura (coneheads);
Cladistically included but traditionally excluded taxa
	Insecta (insects);

**Diplura**, a Two-pronged Bristletail — not closely related to three-pronged bristletails in the Archaeognatha

The Entognatha (from Ancient Greek ἐντός (entós), meaning "inside", and γνάθος (gnáthos), meaning "jaw") are a class of wingless and ametabolous arthropods, which, together with the insects, makes up the subphylum Hexapoda. Their mouthparts are entognathous, meaning that they are retracted within the head, unlike the insects. Entognatha are apterous, meaning that they lack wings. The class contains three orders: Collembola (springtails, 9000 species), Diplura ("two-tail", 1000 species) and Protura ("first-tail", 800 species). These three groups were historically united with the now-obsolete order Thysanura to form the subclass Apterygota, but it has since been recognized that these orders might not be closely related, and Entognatha and Apterygota are now both considered to be paraphyletic groups.