The pupal wing of the Glasswing butterfly, showing cell nuclei (blue), the developing scale surface membrane (magenta) and the internal actin cytoskeleton (green). At this stage, the straight bristle scales have grown quite long while the scales that will form forked bristles look like small triangles. Both contain straight rods of actin. Their reduced size allows light to pass through the wing, appearing transparent. (Credit: Aaron Pomerantz, UC Berkeley and Nipam Patel)