Frenulum

Definition

A small bristle or group of bristles located on the hindwing of certain moths and butterflies, which engages with a hook or retinaculum on the forewing to help hold the wings together during flight.

Etymology

From Latin 'frenulum', a diminutive of 'frenum', meaning 'bridle' or 'restraint'.

Example

The frenulum in hawk moths ensures that the forewings and hindwings move synchronously during flight.

Synonyms

• Wing bristle

Related Terms

• Retinaculum
• Forewing
• Hindwing
• Moths
• Butterflies

Usage Notes

The presence of a frenulum is a key characteristic used to distinguish between different families of moths and some butterflies.