DESCRIPTION: A gall caused by a tiny midge fly that starts out as a small, flattened dome which can be seen on both the underside and upperside of the leaf. The initial colouring is yellow-green but as the gall develops and becomes more columnar the growth becomes more reddish-brown.  The gall itself tends to become more hairy and pointed with age and contain one white larva. When mature the gall falls to the floor where pupation takes place for the adult to emerge the following spring. DISTRIBUTION: Widely distributed throughout the UK. HABITAT: Found on the leaves of Beech trees.