Anthrax anthrax, is a species of fly in the family Bombyliidae but unlike for example Bombylius major this species does not mimic a bee or bumblebee. The eggs are flicked by the adult female toward the entrance of the nests of mason bees. After hatching, the larvae find their way into the nests to feed on the bee larva.Anthrax anthrax can be found in May to August throughout mainland Europe, but probably does not occur in Britain. In the Netherlands Anthrax anthrax is a common visitor of insect hotels.