RES Handbook Vol 1 Part 2. Thysanura and Diplura

THE Thysanura and Diplura comprise two of the four Orders of primitively wingless insects or Apterygota. The Diplura, formerly known as the Entognatha , were formerly ranked as a Sub-Order of the Thysanura but have more recently been given full ordinate status. The Thysanura, sensu stricto, were at that time attributed to the Sub-Order Ectognatha.