The killer fly (Laphria marginata) is a big, black colored, hairy horsefly. The trump, the appearance, its noisy buzzing and even its name are all really frightening. However, we shouldn't panic. It doesn't feed mammal blood, but it hunts over other flying insects. Once the innocent insect is kept, then the killer fly sucks its body. The killer fly plays at insect scale the well known ecological function of the hawk that preds over smaller birds. It is found in clear forests. The larvae grow into spoilt wood. [foto Jordi Badia]