The hoverfly is a true fly and has only two wings. The second pair of wings have been reduced to "balancing balls", called halteres, through evolution. You can see one, slightly out of focus, just behind the wing of this lovely hoverfly. Don't flap with all four wings, evolve and plan ahead. Achieve perfect hoverfly-control by knowing the regulatory obligations for your cosmetic, chemical or biocide and how Brexit may change your business planning from a regulatory perspective.
