from
The Collaborative International Dictionary of English v.0.48
Patagium \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.
[1913 Webster]
2. (Zool.) One of a pair of small vesicular organs situated
at the bases of the anterior wings of lepidopterous
insects. See Illust. of {Butterfly}.
[1913 Webster]