The Bugs

Class Entognatha (springtails)

How Entognatha have been classified has varied over time. They are close to insects however they have distinct differences. Collembola, Springtails, for example have only two obvious body parts wheras insects have 3 body parts. Proturans and Diplurans remain in a grub-like state in appearance and never leave the soil from which they dwell. Entognatha are not classified in the Insecta order however like modern insects they have six legs.

http://www.ento.csiro.au/education/hexapods/collembola.html   for more about springtails

Collembola
Diplura
Protura