Fig. 10. Modulation of hindwing lift depends on the vertical distance between fore- and hindwing wing hinges. The traces show lift modulation similar to Fig. 3C for various distances between the wings measured in mean chord width c, while phase lag systematically varied between -50% (forewing leads by a half stroke cycle) and 50% (hindwing leads by a half stroke cycle). Aspect ratio of the two identical wings=2.7, stroke amplitude=120°, flapping frequency= 666 mHz, wing rotation symmetrical, Re=137.