‖Pa‐ta″gi‐um (?), n.; pl.Patagia (#). 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. (Zoöl.) One of a pair of small vesicular organs situated at the bases of the anterior wings of lepidopterous insects. See Illust. of Butterfly.