Today's Creature: Alcon blue caterpillar 🐛🦋 Phengaris alcon, the Alcon blue or Alcon large blue, is a butterfly of the family Lycaenidae and is found in Europe and across the Palearctic to Siberia and Mongolia. Like some other species of Lycaenidae, the larval (caterpillar) stage of P. alcon depends on support by certain ants; it is therefore known as a myrmecophile. The species can be seen flying in mid- to late summer. It lays its eggs onto the marsh gentian (Gentiana pneumonanthe); in the r