Fig. 1. (A) A female Diprion pini laying eggs on a pine needle. Eggs are laid sequentially in a row (mass) of approximately 10–20 eggs and are covered by a greenish secretion. (B) Cross section through a needle of Pinus sylvestris bearing an egg deposition of the sawfly D. pini. The ovipositing female slits the needle with her ovipositor valves starting at the epidermis (E) of one edge of the needle (arrow) and then cutting the parenchyma (Pa), the endodermis (En), the transfusion tissue (Tr) and one of the vascular bundles (V). After removal of the plant tissue, an egg is placed inside the needle. Ch, egg chorion with oviduct secretion; Y, egg yolk. Finally, the eggs are covered by a secretion (C) from an abdominal gland. Staining with Astrablau (Aldrich, Germany) and Safranin T (Fluka, Germany). Light micrograph. Scale bar, 0.43 mm.