The long-eared bat, Plecotus auritus, often flies about in the crowns of trees hunting insects among the branches. It is very clever in manoeuvering in narrow spaces and hovers easily. It can lift off vertically from the ground, and can move vertically up and down. The purpose of this investigation is to show the principles of the hovering flight; to give a description of the wing-beat cycle and a brief account of the flight mechanics. Hovering in Plecotus auritus is earlier described by Eisentraut (1936).