Parhelophilus species
The genus Parhelophilus is comprised of three extremely similar species: Parhelophilus versicolor, Parhelophilus consimilis and Parhelophilus frutetorum. They all do look a lot like the Striped Hoverflies, but they are more orange all over and definitely more hairy. Telling the species apart is far from easy, even from photographs. The first thing you have to look at is the tibia of the front leg. In Parhelophilus consimilis the top is black. In the other two species the top is yellow, except for a very small black smear. Also Parhelophilus consimilis needs a certain environment: peat. The other two species are not that choosy. So, how to tell apart the other two species? The worst news is that the females can not be told apart without killing them and opening them up, for the only difference is within the genitals. Especially when handled males can be told apart, though. You have to look at the underside of the femur of the hind leg. The underside is plain in Parhelophilus versicolor. In Parhelophilus frutetorum however there is a small, hairy hump.
Parhelophilus frutetorum is a common species all over the northern hemisphere, including Southern Britain. It is usually found on vegetation near water and the larvae have been found inside the stems of club rush. Adults are on the wing from April till October, but the numbers are peaking in June.
Parhelophilus versicolor is a widespread European species, usually found in lush vegetation near water. The larvae have been found feeding on decaying bulrush. It is on the wing from April till August, peaking in July.
Parhelophilus consimilis is rare in England and Wales, but it does occur in Scotland and Ireland as well. It is mainly found in peat, but also in some lakes and even in brackish waters along the coast. The larvae are feeding on decaying plants in the water. Adults are seen from May to mid-July, but most recordings are made in May.
