Birch sawfly larva / Larve du Tenthrède du bouleau Beginning in June, the female, which is wasp-like with silvery membranous wings, cuts a network of slits along leaf margins and deposits her eggs in them. In July, groups of larvae can be readily observed around the leaves, which they consume right down to the midrib. At the end of its larval development, the insect falls to the ground and weaves a silky cocoon in which it overwinters as a prepupa in the litter.
