In late summer, people often say that now flies have started to bite. It is not the common house fly, which has suddenly become aggressive, but its close relative the stable fly, Stomoxys calcitrans.
It is mostly common in the fall, but can also be a nuisance during spring and summer. A stable fly looks like an ordinary house fly, but is characterized by its hard, pointy proboscis which clearly sticks out of the front of the head – like a stick.
When sitting on a wall, you can recognize the black flies because their wings are further apart and they usually sit with their heads facing upwards, while the majority of house flies face their heads downwards.