Humpbacked flies (phorid flies)
Jeff Hahn, University of Minnesota
University of Wisconsin
Size: 1/8 inch long
Description: Body is brownish with conspicuous hump shape when viewed from the side; wings with few veins; commonly found running erratically.
Where/When: Humpbacked flies are found indoors in any room where decaying organic matter is found, such as trash containers, drains, and plumbing or sewer leaks. They can be found anytime during the year.
Significance: Humpbacked flies are primarily a nuisance because they can occur in large numbers. They are generally not considered a health problem; however, they can potentially be a mechanical vector of disease-causing bacteria.