Flies are the fourth largest group of insects in the world consisting of more than 110,000 species. Flies can be found in every part of the world especially in tropical and subtropical areas. Files can detect food from inside houses or outdoors from garbage cans and will breed in drains or garbage containers leading to a high population in those areas. With over 110,000 species of flies each fly has a different strategy for control, there are 3 main flies you may encounter in Ontario infesting your home.