Pigment responsible for the red, orange and yellow color spots on the wings of butterflies. Has been detected also in the integument of other insects. Isoln: C. Sch"opf, E. Becker, Ann. 524, 49 (1936). Structure: R. Tschesche, H. Ende, Ber. 91, 2074 (1958). Revised structure: W. Pfleiderer, ibid. 95, 2195 (1962). Synthesis: M. Viscontini, H. Stierlin, Helv. Chim. Acta 46, 51 (1963). Correlation to body coloration: E. J. Pfeiler, Jr., J. Res. Lepid. 7, 183 (1968); C. Melber, G. H. Schmidt, Comp. Biochem. Physiol. 116A, 17 (1997). Quantification: eidem, ibid. 101B, 115 (1992); Y. Bel et al., Arch. Insect Biochem. Physiol. 34, 83 (1997).