Usually, the larva leaves the breeding material and moves to a dry, protected place just before becoming a pupa. The pupa is an inactive stage, like a cocoon, in which the adult fly develops. After leaving the pupal case, adult flies mate and the females begin to lay eggs. Adult flies may live for several weeks. There are three types of domestic flies commonly found around homes and businesses - house flies, bottle or blow flies, and flesh flies.
Houseflies are grey and black with four black stripes on the back.
They are about inch long. Eggs are laid on decomposing organic matter, either plant or animal. Female houseflies lay eggs in batches of 50-100, and as many as 500 eggs may be laid in a lifetime. Depending upon the temperature, it may take as little as 10 days from egg to adult. A very similar looking relative of the housefly is the stable fly , sometimes called the dog fly.