Definition of robber fly in English:

robber fly

noun

  • A large, powerful predatory fly which darts out and grabs insect prey on the wing.

    • ‘The nerve toxins immobilize the hapless insect, while the digestive enzymes turn its innards to mush, which the robber fly consumes.’
    • ‘Grasshoppers here and in other grasslands are readily eaten by both vertebrate and arthropod predators (including robber flies and especially spiders).’