What structure allows the forewing and hindwing of many moth species to work together as a single aerodynamic surface?

Answer

A system of hooks and bristles called a frenulum

In many species, the forewing and hindwing are coupled together by a system of hooks and bristles (called a frenulum), allowing them to work together as a single aerodynamic surface during flight.

What structure allows the forewing and hindwing of many moth species to work together as a single aerodynamic surface?
insectmothanatomycharacteristicphysical