DESCRIPTION: Approximately 6 - 8mm in length. A lovely Tephrid Fly with large ginger-green eyes, a grey thorax and a black abdomen.  The milky wings have distinctive dark cross bands. The scutellum and the sides of the thorax are pale cream. BEHAVIOUR: The female lays her eggs in the flower heads of Thistles, usually Spear Thistle, causing them to swell and damage seeds. They are sometimes used in weed control against Thistles. DISTRIBUTION: Widespread in the southern half of Britain, becoming less so in more Northern areas. HABITAT: Meadows, woodland edges and hedgerows where Thistles grow. PERIOD: Mid June to September.