Fig. 2

FESEM images of original butterfly scales in the black region with different magnifications. a Lower magnification image. It was found clearly that these scales ranged in good order on the substrate. b, c Medium magnification image. This surface of the scale comprised a set of raised longitudinal quasi-parallel lamellae (ridges), the space between which was filled with a quasi-honeycomb-like structure. d The high-magnification images of the quasi-honeycomb-like structure