Fig. 3

Light micrographs, scatterograms and reflectance spectra of isolated wing scales. a-e Blue scale. f-j White scale. k-o Orange-yellow scale of the dorsal forewing. p-t Orange-yellow scale of the ventral forewing. a, b, f, g, k, l, p, q Epi-illumination light micrographs of the abwing side (1st column) and adwing side (2nd column); scale bar: 50 nm. The numbers 1–3 and 7 in a, f, k, and p correspond with the numbered areas in Fig. 1b, e. 3rd column: Scatterograms of the abwing and adwing side; the red circles indicate scattering angles of 5°, 30°, 60°, and 90°. 4th column: Reflectance spectra of the ab- and adwing sides and of chitinous thin films with thicknesses of 275, 190, 380, and 300 nm