There are over 200 species of hoverfly in the UK, with a wide range of appearances. All hoverflies belong in the family Syrphidae, and share the characteristic of a 'spurious' vein in the wings, which does not terminate in another vein or at the edge of the wing. In most cases hoverflies are easily recognised and this characteristic will not need to be checked. Most UK hoverflies can be identified from external characteristics, although in some cases this will require recourse to a specimen. For a few species, most notably those in the genus Sphaerophoria, it is necessary to refer to the genitalia to confirm the identification. The best resource for hoverfly identification is Stubbs and Falk's guide to British hoverflies.