DESCRIPTION: Up to 4mm in length.  Also known as the Red-Tailed Thistle Fly this gall-inducing species is best identified by its green eyes, orange frons, grey thorax and abdomen that have black markings and the clear wings that bear two broken bars and a dark patch at the tip. BEHAVIOUR: The larvae of this species are responsible for the formation of galls in the seed heads of Creeping Thistle. DISTRIBUTION: Fairly common throughout southern Britain. HABITAT: Found wherever Creeping Thistle grows in great abundance, especially grasslands, headgerows and field margins. PERIOD: May to July.