larva

Latin larva (plural larvae) meant 'ghost,' 'evil spirit,' or 'mask' — particularly the theatrical masks worn in Roman drama. When Carl Linnaeus needed a term for the juvenile stage of insects in 1735, he chose larva because the caterpillar, grub, or maggot is a mask concealing the adult insect within. The chrysalis reveals the truth. The larva hides it. The metaphor is precise: what you see is not what the creature actually is.

Linnaeus's choice was poetic but scientifically accurate. Holometabolous insects — those that undergo complete metamorphosis — transform so thoroughly between larval and adult stages that the two forms are often unrecognizable as the same species. A maggot becomes a fly. A caterpillar becomes a butterfly. A grub becomes a beetle. Inside the pupal stage, most larval tissues dissolve entirely, and the adult body is rebuilt from clusters of cells called imaginal discs that have been dormant since the egg stage. The ghost truly does become something else.

The Roman larva — the ghost — was a specific kind of spirit. Roman religion distinguished between lares (benevolent household spirits) and larvae or lemures (malevolent ghosts of the wicked dead). The Lemuria, a festival held on May 9, 11, and 13, involved rituals to banish larvae from the household: the head of the family walked barefoot at midnight, throwing black beans over his shoulder while chanting nine times. Ovid describes the ritual in his Fasti. The larvae were hungry, angry, and persistent.

English borrowed larva in both its senses: the scientific term for juvenile insects (1768) and the Roman ghost (earlier, through literary texts). Most English speakers know only the insect meaning. The ghost meaning survives in the word 'larval,' which occasionally appears in horror fiction. Linnaeus bridged the two meanings with a single insight: the creature you see is wearing a mask. The real form has not yet appeared.