Insect Classification - Subclass Apterygota

The name Apterygota is Greek in origin, and means "without wings." This subclass contains primitive hexapods that do not fly, and were wingless throughout their evolutionary history. 

The primitively wingless hexapods undergo little or no metamorphosis. Instead, the larval forms are smaller versions of their adult parents. Apterygotes molt throughout their lives, not just during the growth phase. Some apterygotes, like silverfish, may molt dozens of times and live several years. 

Three of the five orders classified as Apterygota are no longer considered true insects. Diplurans, proturans, and springtails are now referred to as the entognathous orders of hexapods. The term entognath (ento meaning inside, and gnath meaning jaw) refers to their internal mouthparts.

• Diplura - diplurans (Entognatha)
• Protura - proturans (Entognatha)
• Collembola - springtails (Entognatha)
• Thysanura - silverfish and firebrats (Insecta)
• Microcoryphia - jumping bristletails  (Insecta)

_Sources:

• _{"Apterygota," by John R. Meyer, Department of Entomology, North Carolina State University. Accessed online October 29, 2015.}
• _{Hexapod taxonomy lecture slides, by Christopher Brown, Department of Biology, Tennessee Tech University. Accessed online October 29, 2015.}
• _{Borror and DeLong's Introduction to the Study of Insects, 7th edition, by Charles A. Triplehorn and Norman F. Johnson.}