Eristalinus megacephalus is a species of hoverfly which can be found in non-marine areas of numerous countries in Africa, Europe, and Asia. First described by Pietro Rossi in 1794, its name emphasizes the size of its head. E. megacephalus, which averages 8–11 millimetres (0.31–0.43 in) in length, uses Batesian mimicry to resemble a bee or other hymenopteran and thus scare away predators.Photograph: Muhammad Mahdi Karim