Campodea

Campodea, a minute insect of the order Thysanura; it is wingless, has only six openings to the breathing tubes (tracheae), and is of especial interest from the possession of rudimentary limbs on the abdomen (compare this with the cercopoda of cockroaches). From this character, the complete absence of wings in all stages of development, and the general resemblance to the Myriapoda, Campodea is regarded as about the most primitive of living insects. Some higher forms pass in development through a stage resembling this genus; this is known as the "Campodeiform" stage.