Fig. 8. Scrutiny of a constant-speed approach path towards the predicted point of impact. (A) Path of falling fly (open circles, calculated projection onto the plane of the water surface) and of responding fish (filled dot indicates the head) sampled every 20 ms. For the fish, only every second sample is shown. (B,C) The corresponding time course of (B) speed and (C) angle. The phase of rapid turning is shown by grey shading. Three filled dots indicate the speed determined in the first, second and third interval of 20 ms duration after take-off. The impact of the fly is indicated by an arrow. Sequence ends with the catch. In B, speed values report translational speed except for the phase of turning (grey shading) in which values report only the change of head position that was due to turning. During translation the speed is approximately constant. Note that speed could not be estimated better than about 0.05 m s^-1. (C) After an initial turn of about 30°, the bearing is maintained. A bearing of 0° denotes a course in the orientation of the scale bar in A (0.1 m).