Thysanura

Thysanura, an order of wingless insects of small size. They undergo no metamorphosis. The abdomen usually bears peculiar structures, which seem to be abortive limbs, and the name Thysanura or bristle-tails refers to terminal appendages which are sometimes long and hairy. See SPRING-TAILS; and Sir John Lubbock, Monograph of the Collembola and Thysanura (Lond. 1873).