A

David

Darling

halteres

crane fly with halteres labeled

Halteres are two knob-like structures found in two-winged insects that take the place of functioning hind wings. When in flight the insect vibrates the halteres rapidly so that they act like gyroscopes, helping the insect maintain stability and maneuver precisely. Crane flies, such as the one illustrated here, have particularly visible halteres.