Halteres

In Dipterous insects, halteres (/hælˈtɪəriːz/; singular halter or haltere), are minute dumbbell shaped organs that have been modified from hindwings to provide a means of encoding body rotations during flight. Halteres are rapidly oscillated simultaneously with the wings, allowing them to experience forces resulting from body rotations. If the body of the insect rotates about one of its three axes (yaw, pitch or roll), the rotation exerts a force on the vibrating halteres, known as the Coriolis effect (see below). The insect detects this force with sensory organs called campaniform sensilla and chordotonal organs located at the base of the halteres and uses this information to interpret and correct its position in space. Halteres act as a balance and guidance system by providing rapid feedback to the wing-steering muscles, as well as those responsible for stabilizing the head. This is what allows flies to perform their fast acrobatics maneuvers.