Larvae and puparia of Tephritidae were found in flower heads of Cirsium arvense (L.) Scop. from late July to mid September. Many seeds and anthidia of the flowers were damaged. Five species of flies were reared: Chaetostomella cylindrica (R.D.), Orellia ruficauda F., Tephritis cometa Loew., Urophora solstitialis L. and Xyphosia militariae Schrank. The Tephritidae larvae were found to be parazitized by three species of Hymenoptera: Crataepus marbis (Walk.), Habrocytus musaeus (Walk.) and Bracon minutator (F.).