belongs to the hoverflies and is a very keen flower visitor and pollinator. Here it is visiting Knautia arvensis.
The larvae develop in an anaerobic environment in wet decomposing materials, preferably in ditches or in the border of wetlands. Having a wild garden pond makes it thrive. To be able to live in wetlands and ponds they have developed a long extension tube in their abdomen, through which they can breathe. In English they are called rat-tailed maggot.