This species has a wingspan of about 50mm. The body is yellow with short black stripes on the thorax and a black line on each section of the abdomen. The wings have a thin line by the leading edge that is yellow in colour.
The larvae, known as "leatherjackets", feed on roots.
In flight May - September.
Information Source: http://en.wikipedia.org/wiki/Nephrotoma_appendiculata.