Abstract. Schinia scissa (Grote) is endemic to Florida and one of the most rarely-encountered North American flower moths (Heliothinae), known to science from less than 10 specimens for nearly 150 years. The life history and larval host plant, previously unknown, is documented here for the first time. Larvae feed on the flowering parts of Arcadian St. John's Wort (Hypericum edisonianum, Hypericaceae), and circumstantial evidence indicates other Hypericum species may be suitable hosts as well.