DESCRIPTION: Up to 3mm across and 1.5mm deep the galls of this species are circuluar and are located alongside the leaf blade or over the leaf veins. They are yellowish-green in colour at first becoming reddish with age, especially around the outer part which can form a ring. The larva of the causal midge is pale yellow with a conspicious sternal spatula and indistinct head section. DISTRIBUTION: Frequent throughout Britain. HABITAT: Found on the leaves of various Birch species from July to September.
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