Results of experiment 4.

<p>(A) As Fig. 1A for the test surfaces used in experiment 4 when the optical axis of the polarimeter was horizontal. In the α-patterns the short bars represent the local transmission direction of the linear polarizer. (B, C) Number <i>N</i> of tabanids captured by the vertical and horizontal test surfaces in experiment 4. S16+: test surface with 16 linearly polarizing squares, the transmission direction of which is perpendicular to that of their surrounding regions. S4+: test surface with 4 linearly polarizing squares, the transmission direction of which is perpendicular to that of their surrounding regions. S16−: test surface with 16 linearly polarizing squares, the transmission direction of which is parallel to that of their surrounding regions.