They also carry cholera and intestinal worms. Blow flies, like Houseflies, will live on feces, meat scraps in garbage, wet mixed garbage, and dead animals. Similarly, they can also contaminate food. In some Blow flies, the eggs hatch while still within the female, and she will deposit live larvae, preferably on raw meat and sometimes on festering cuts and sores where the larvae will feed on the living tissue. If these larvae are accidentally eaten, the hardy maggots continue to grow, irritating the stomach and intestine, causing nausea, vomiting, and severe diarrhea.
Cluster flies are larger than the previous flies, and seem sluggish in comparison.
They can be identified by yellow hairs on the thorax. The larvae develop as parasites in the bodies of earthworms, and the adults emerge in late summer and early fall. These adult cluster flies seek protected places to spend the winter, and will frequently end up in the walls and ceilings of buildings. They enter through small openings, such as wire penetrations, cracks around windows, openings around the roof, etc. These flies will come out of hiding in the spring or on warm winter days, and cluster around windows in an attempt to enter.