Definition of 'hind wing'

Hind wing: The rear pair of wings of an insect, which are attached to the metothorax, the same thoracic segment that bears the hind legs. In mayflies, the hind wings are much smaller than forewings, and in rare cases absent. In caddisflies, they are the inner wings, covered by the fore wings, when the wings lay at rest over the body. In stoneflies, they are the bottom wings, covered by the fore wings, when the wings are laid flat over the body. Midges and other true flies do not have true hind wings.

These other words reference the same concept: hind wings, hindwing, hindwings.