The Birch sawfly (Cimbex femorata) is an insect of the family Cimbicidae, usually black in colour, found flying awkwardly in European and Siberian birch woods during May and June. The eggs are laid in the leaves of the birch tree. The larvae resembles a caterpillar, has eleven pairs of extremities, is slow-moving and light green in colour with a dark dorsal stripe and dark spots round the spiracles. The larvae rest on the underneath of birch leaves during the day, feeding on birch leaves at night. When threatened they spray haemolymph to a distance of 20 cm. Research Birch Sawfly