House Flies, sometimes known as a Filth Fly are nuisance, non-biting pests that have a world-wide distribution and are known for contaminating food and spreading serious diseases to people. The most common filth fly species that people come into contact with is the house fly. House flies are dull gray in color and are about 1/8th-1/4 of an inch in length. They have black vertical lines on the top of their bodies; adults have one silver stripe and one gold stripe on their face. Other common species of filth flies include: blow flies, bottle flies, flesh flies, and soldier flies.