Evidence from free-flight cinematography, dissection and manipulation suggests that the fulcroalar muscle in Odonata facilitates wing profile change between Cu and R+M at the start of, and sometimes during, the downstroke by providing some of the power needed to deform the axillary complex. The flexion is completed primarily by the first basalar and second subalar depressors. The fulcroalar muscle may also influence wing deformation at the start of the upstroke. Sectioning shows that it is a single muscle, not two as has been suggested.