Thus, the molecular mechanisms responsible for green coloration, especially the combination of blue and yel- low pigments, are still largely unknown. Recently we identi- fied two genes, bilin-binding protein (BBP) and yellow-related gene (YRG) as green coloration associated genes from P. xuthus larvae (Futahashi and Fujiwara 2008a, b). In P. polytes larvae, blue spots exist in V-shaped markings (Figs. 1, D and 2, arrows), and in P. machaon, many yellow spots exist in the black band markings (Figs. 1, D and 2, arrowheads). To un- derstand the relationships between these two genes and blue and/or yellow coloration more clearly, we compared gene ex- pression pattern in three Papilio species.