patagium

A thin membrane extending between the body and a limb to form a wing or winglike extension, as in bats and flying squirrels.

An expandable membranous fold of skin between the wing and body of a bird.

In zoology: The extensible fold of skin of a flying mammal or reptile; the expansion of the integument of the trunk and limbs or tail, or both of these, by which bats, flying-lemurs, flying-squirrels, flying-opossums, and flying-lizards support themselves in the air.

The fold of integument which occupies the reëntrant angle between the upper arm and the forearm of a bird, bringing the fore border of the wing to a smooth straightish free edge when the wing is closed. The tensor patagii is a muscle which puts this patagium upon the stretch.

In entomology, one of a pair of chitinous scales affixed to the sides of the pronotum of lepidopterous insects, just behind the head, usually covered with long scales or hairs; a shoulder-tippet. Compare tegula.

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.

One of a pair of small vesicular organs situated at the bases of the anterior wings of lepidopterous insects. See Illust. of Butterfly.

The thin membrane that extends between the limbs and body of a bat or of gliding mammals

A similar membrane between the body and wing of a bird