Structural data and spectra for: Micro-optics in the cuticle of matt-green <em>Chrysina</em> beetles create spatially-projected images

Matt-green Chrysina beetles show left-handed circularly polarised light reflections produced by a helicoidal chitin-protein fibres structure. We provide tables for the Structural Pitch (a full 360 degrees turn) of the helicoid of C. chrysopedila, C. boucardi and C. bruyeai. These species have an exocuticle with small craters and rims that spread local specular reflections in many directions and show up under the microscope as a polygonal structure. We provide reflection spectra measured at different depths by using a microscope with a coupled variable-aperture spectrophotometer. Also, we provide circularly polarized spectra measured at the crater centres, off-centres at the slope, and at the rims separating the craters.