Rapala cassidyi, the Cassidy's flash is a lycaenid butterfly found in Sulawesi.[1] It was discovered in 1985 during the Project Wallace expedition of the Royal Entomological Society.[2] The female remains undescribed.[1]
The species lives in northern Sulawesi, Indonesia, in Bogani Nani Wartabone National Park.
The upperside of the male is unusual in that it has only a small amount of pale orange on the discal area of the forewing below the cell; a pattern more reminiscent of females of the genus. The underside ground colour is light slate brown with a glossy sheen. The usual postdiscal striae or the genus are present in an ochreous colour and there is a diffuse ochreous marginal band on both wings.