DESCRIPTION: Caused by the larva of a fly this gall is formed when the tip of the pinnule and several nearby pinnules roll downwards and slightly discolours.  If one cares to examine more closely a white maggot can be found feeding along the main vein. DISTRIBUTION: A widespread and easily seen wherever the host plant is found. HABITAT: Found on the fronds of Bracken which is of course, a quite ubiquitous plant.