Fig. 4

The lattice of scales on the wing. a Epi-illumination of the transition area of a white spot in the blue area on the dorsal forewing, showing a similar blue stripe on the light- and dark-colored scales. b-d Epi-illumination light micrographs of an orange-yellow wing area on the dorsal forewing, with a few missing scales in the center. b Normal illumination with linearly polarized light (parallel polarizer and analyzer). c Idem with a crossed polarizer and analyzer. d Oblique illumination (~ 45°) with unpolarized light. The numbers 1–3 in a and c correspond to the numbered areas in Fig. 1b, e. Scale bars a-d: 200 μm