\Pa*ta"gi*um\, n.; pl. {Patagia}. [L., an edge or
border.]
1. (Anat.) In bats, an expansion of the integument uniting
   the fore limb with the body and extending between the
   elongated fingers to form the wing; in birds, the similar
   fold of integument uniting the fore limb with the body.
2. (Zo["o]l.) One of a pair of small vesicular organs
   situated at the bases of the anterior wings of
   lepidopterous insects. See Illust. of {Butterfly}.