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.