Platycheirus rosarum, is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of hoverfly

Hoverfly

Hoverflies, sometimes called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while the larvae eat a wide range of foods...

 found in many parts of Britain

Great Britain

Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

 and Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

. Like it's close relative Platycheirus granditarsus

Platycheirus granditarsus

Platycheirus granditarsus is a species of hoverfly. It is found in many parts of Britain and Europe. Typical habitat includes marshy meadows and ditches, where it can be found between May and October though it is at its commonest between July and September. The most distinctive feature of this fly...

it can be found in marshy meadows and ditches. Indeed the two species can often be found together. The flight time is between May and October though it peaks in abundance in June and July. The most distinctive feature of this fly is the pair of yellowish spots on tergite 2 on an otherwise completely black abdomen.