They feed on solid food by regurgitating saliva onto it. The saliva liquefies the solid material, which is then sponged up with the proboscis. They require water since they continually salivate and void liquids. Fly specks seen on surfaces visited by house flies are the excreted wastes. Female house flies deposit their eggs in decaying matter such as grass clippings, garbage, and human and animal excrement.
Horse manure is the preferred breeding medium.
Each female deposits about 100-150 eggs on appropriate food. Eggs hatch into worm-like creatures called maggots. Maggots lack definite heads, eyes, antennae, and legs. Their bodies are pointed at the front end and gradually widen at the rear. Fly maggots feed on the material in which they find themselves.