Fig. 1. Methods. (A) Schematic cartoon showing method of data collection (not drawn to scale). Tethered flies were positioned within view of three orthogonally arranged high-speed video cameras. A panel of infrared LEDs was placed opposite each camera to provide backlighting. (B) Sample video frame from each camera view. A wire frame image of a Calliphora wing (shown in yellow and red) was fit by eye to the outline of each wing in all three camera views simultaneously. The anterior tip of the head (blue cross) and the posterior tip of the abdomen (pink cross) were digitized once per sequence. (C) The wing's position at each time point was quantified relative to a 50°-tilted body axis (left). The progression of the three Euler angles (, and ) over time was reproduced using a mechanical model fitted with force transducers at the base of the model wing (right).