Maggots are the larva of flies. A maggot's life cycle in a dead body varies according to species and environmental conditions. Because the development of maggots can be consistently calculated, maggots have been used by endocrinologists to determine the time of death of the host body.
When a body dies outdoors, blowflies arrive within 10 minutes of death. A female will lay about 300 eggs while she feeds on decaying flesh.
It takes eight to 20 hours for maggots to hatch from their eggs, and they are about 2mm long when they emerge.
Maggots go through a total of three instars (stages between moults). Going from the first to second instar takes 24 hours, during which time the maggot will grow to be about 5mm long. Second-instar maggots grow to be about 10mm in 24 hours and then moult into their third-instar, growing to 15 to 20mm in 48 hours.
Maggots will go through two more stages of development before they become adult flies. These are called the pre-pupa (lasting four days) and pupa (lasting 10 days).
The scientific name for the blowfly is Sarcophagi, meaning "corpse eater."