Fig. 2. Method for measuring positions of the antenna, head and foreleg. (A) Top view (i) depicts horizontal angular positions of the right antenna and the foreleg, and yaw position of the head. Lateral view (ii) is a diagram for the antennal vertical and head pitch positions. (B) Relationships of parameters for the antennal (i) and head (ii) positions. Note that three-dimensional coordinates for antennal (i) and head (ii) positions are different from each other. The rostrocaudal y axis for the former is identical with the head axis, and the latter (y' axis) with the body axis. See Materials and methods for details of these parameters. O, origin for both antennal and head positions; O', origin for foreleg position; P, plotting point registering antennal position; P', plotting point registering foreleg position.