Fig. 4. Traces of landmark dots on the elytra in Prionus coriarius in two projections in the external reference system during opening and closing. Top panel: rear view in the real image, bottom panel: top view in the mirror. For designations see Fig. 2. Note (i) parallel rising at the start of opening and sinking down at the finish of closing (box in the top panel) and (ii) traces of wingbeats of the elytra after opening and before closing seen as mushroom heads in both panels. Zero pitch, 9 episodes, 157 frames.