There exists thousands of fly species belonging to the Diptera order of insects that have been documented as existing in almost all areas of the world. Some of the most commonly encountered, and widely distributed fly species include the common housefly, the black fly, the fruit fly, the horse fly and the stable fly. The common housefly (Musca domesticus) is the most commonly encountered Diptera fly species within homes and buildings.

Due to the similarity in appearance between numerous fly species, it is not uncommon for residents to wrongly assume that the flies infesting their home or yard are common houseflies. The stable fly is one species that bears a particularly close resemblance to the common housefly. Unlike the housefly, however, the stable fly is capable of biting humans. The false stable fly is significantly larger than the stable fly, and while both of these species  are considered indoor pests in urban and residential areas, the false stable fly is encountered far less often.

The common housefly grows to be around 5 to 7 mm in length, while the stable fly grows to be 4 to 6 mm in length. The stable fly’s checkered abdomen and its habit of biting humans and animals are the most significant factors that distinguish this species from the common housefly. Unlike the stable fly, the false stable fly grows to be around 10 mm in length, and luckily, this species does not bite.

Both the stable and false stable fly species are well established in Massachusetts where the stable fly is known for inflicting painful bites to humans in coastal areas. However, researchers claim that stable flies only bite animals, while bites to humans are often accidental, with the exception of bites inflicted upon beachgoers. Since stable flies breed in coastal areas, they are territorial and aggressive toward both humans and animals in these regions, and therefore, will not hesitate to inflict bites.

While the stable fly can inflict painful bites, they do not spread disease to humans, and therefore, this species is not considered a significant public health threat. However, both the stable and false stable fly species can maintain a nuisance infestation within a home or building. Once these infestations become established, they are, like most Diptera fly infestations, notoriously hard to eradicate.

Have you ever sustained a fly bite in any region of the world?