Three-dimensional photonic crystals in weevils and longhorn beetles. (a) Pachyrrhynchus congestus pavonius (Curculionidae: Entiminae), SEM of crystal structure from scale interior (from Welch & Vigneron 2007), (b) SEM of the interior structure of Prosopocerus lactator (Cerambycidae: Lamiinae), (c) Pachyrrhynchus gemmatus, light photograph of opalescent scale patch, (d) P. gemmatus, habitus view.