Cluster flies are found throughout North America and Europe, and probably originated in North America during the colonial days. They are large dark gray to black flies that resemble houseflies in appearance; however, they are larger and, in reality, are not related to houseflies at all. In fact, they are in the same family as blowflies and flesh flies. To differentiate between houseflies and cluster flies, look at the wings of the fly at rest. Cluster flies’ wings overlap like a pair of scissors, while houseflies’ wings do not. Additionally, cluster flies have golden hairs on their thoraxes. When crushed, cluster flies emit a smell that resembles that of buckwheat honey.