DESCRIPTION: The chemically induced distortions of the developing buds are caused by a tiny mite. Each gall is made up of layers of thickened leaves that are noticeably hairy. Galled buds appear light green at first and turn brown later in the year. In the autumnal months the mites leave the old bud and take up residence in a new bud or newly formed male catkins where they remain inactive between the flower scales until late winter. When the catkins start to elongate, the mites feed and cause the scales to swell and the stamens to distort and disappear. The following spring the females migrate to new catkins and buds where they feed and lay eggs. DISTRIBUTION: Frequent throughout but easily overlooked. HABITAT: On the buds of Hazel trees. There is a vagrant form that feeds on the vegetative and generative parts such as leaves, male and female flowers.