Fig. 1.

Three exemplary Morpho butterflies, M. epistrophus (a–c), M. helenor (d–f), and M. cypris (g–i). a, d, g Photographs of the left wings. b, e, h Bright-field micrographs of a small area indicated by the red lines. c, f, i Dark-field micrographs of the same areas. In the micrographs of M. epistrophus (b, c) a cover and ground scale are indicated by a solid and dashed line, respectively. The asterisks in the micrographs of M. helenor (e, f) indicate an area where the cover scales were removed; cover scales are unpigmented and have a rounded tip. The asterisks in the micrographs of M. cypris (h, i) indicate an iridescent, pigmented scale. Bar i 200 µm