1911 Encyclopædia Britannica/Thysanura

THYSANURA, the name applied by P. A. Latreille to the primitive wingless insects known as springtails and bristletails. Sir J. Lubbock (Lord Avebury) separated the springtails as a distinct order, the Collembola, and by many students this separation has been maintained. It is better, on the whole, to regard the Thysanura and Collembola as sub-orders of a single order, the Aptera (q.v.). The Thysanura are recognizable by their elongate feelers and tail-processes (cerci). Campodea (q.v.) Machilis and Lepisma—to which belongs the “silverfish” (q.v.)—are the best known genera. (See also Hexapoda and Aptera.)