HORNET-Fly, in natural history, a very large two-winged fly, which has the shape and colours of the hor-
Horning hornet, and is at first sight scarce to be distinguished from it. The principal colour of the body of this fly is yellow; but it has two long and large black lines placed transversely upon it, and has a black corselet and a yellow head. These lay, at a proper season, a large number of oblong white eggs, which hatch into large and long worms, whose chief food is the worms and nymphs of the humble bees. The worm of this fly is continually found in the nests of these bees, where it never meddles with the wax or honey, but preys only upon the young offspring of the creature.