It is somewhat smaller (3.5–6 mm (0.14–0.24 in)) than the common housefly and is best known for its habit of entering buildings and flying in jagged patterns in the middle of a room.

Larvae feed on all manner of decaying organic matter, including carrion.

The eggs, which are white with a pair of dorsal longitudinal flanges or wings, can float in liquid and semiliquid decaying organic matter, especially poultry, cow and dog feces, kitchen waste such as the end of putrid potatoes or carrots, silage and compost, cheese, bacon, and drying fish.

[2] From May to October, the lesser housefly comes frequently into buildings and is noticeable by its peculiar, silent flight in the room center, where it circles down-hanging articles, particularly lamps.

During short breaks and in the night hours, the flies sit on lamps or on walls and leave their small excrement marks.