Helophilus (tiger hoverflies)
Conspicuous hoverflies with a boldly striped thorax and a broad, flattened abdomen bearing yellow and black markings augmented by grey spots. Males are unusual for hoverflies in having eyes that do not meet at the top although they are less widely seoarted than in females. Parhelophilus species are similiar but smaller, furrier and duller-looking with orange antennae. Helophilus species have aquatic 'rat-tailed' larvae that usually develop in organically-rich water. The adults are keen flower-visitors and can turn up far from breeding sites, notably H. trivittatus which is strongly migratory. Three species are widespread in Britain, with records of two further boreal species (possibly vagrants) known form the Scottish coast and offshore islands. Three further European species exist.