Tabanus sudeticus, also known as the dark giant horsefly, is a species of biting horse-fly. It is the heaviest fly in Europe.
The dark giant horsefly's length is around 20-25 millimeters. They have uniform dark brown eyes.
Dark giant horseflies are a common species to be found buzzing around cows and horses. They usually only suck blood from those horses and cows, avoiding humans. They fly with a very loud buzzing.
Tabanus sudeticus is found in many countries of Western Europe. It has a marked northern and western distribution; being found as far north as southern Norway and the Western Isles of Scotland, and with an occasional record from Belarus.