The Collaborative International Dictionary of English v.0.48:

Aptera \Ap"te*ra\, n. pl. [NL. aptera, fr. Gr. ? without wings;
   'a priv. + ? wing, ? to fly.] (Zool.)
   Insects without wings, constituting the seventh Linn[ae]n
   order of insects, an artificial group, which included
   Crustacea, spiders, centipeds, and even worms. These animals
   are now placed in several distinct classes and orders.
   [1913 Webster]