a.k.a Episyrphus balteatus, it's a kind of fly that looks similar to a wasp, but smaller and narrower. Called the hover fly because it can hover in one place, its' wings beat 300 times per second. They often hover in one place then suddenly zoom away, but can also move about slowly through the air. Some are silent, but some make a really irritating high-pitched buzz.

Despite the fact that they have yellow and black stripes, and drink nectar from flowers, they are just flies and cannot bite or sting. The yellow stripes are an evolutionary advantage. Since insects or reptiles that are poisonous or can sting are often coloured this way, other animals have in time learned to avoid species of this colour, hence Hover Flies have a greater chance of survival. It's interesting that people who are afraid of bees and wasps are usually afraid of Hover Flies too because of their colour.