This was taken using the Canon 50mm f/1.8 on top of which was fitted a reversed Minolta 50mm f/1.7....

Here's some nice info about your frequent house quest:

Musca domestica Linnaeus

The control of Musca domestica is vital to human health and comfort in many areas of the world. The most important damage related with this insect is the annoyance and the indirect damage produced by the potential transmission of more than 100 pathogens associated with this fly. These may cause disease in humans and animals, including typhoid, cholera, bacillary dysentery, tuberculosis, anthrax ophthalmia and infantile diarrhea, as well as parasitic worms. Pathogenic organisms are picked up by flies from garbage, sewage and other sources of filth, and then transferred on their mouthparts and other body parts, through their vomitus, feces and contaminated external body parts to human and animal food.