DESCRIPTION: Starting off with a yellowish erinea that eventually becomes red. Concave below the leaf surface, convex above the mite induced galls are usually found in small spaced out groups on individual leaves. The broad tipped hairs on the lower surface of the gall (in which the mite lives) start off pale and become brownish. DISTRIBUTION: Common throughout. Spring to late summer. HABITAT: Common on Aspen and less so on Poplar species.