The larva of a fly is usually known as a maggot. They mostly look like worms or tiny caterpillars and live in food, rubbish, soil, water and dead plant and animal material. A fly larva spends most of its time eating and growing and then moults by shedding its skin. This process occurs several times as it grows to adult phase. The larva then changes to a pupa which is the next stage of the life cycle.