Scribbly Gum Bark. Eucalyptus racimosa. On the bark of this tree there are markings that at first look man made. However, they are made by a moth larvae which lays its eggs on the bark of the tree. The eggs develop into larvae, which wind back and forth looking for sugar in the sap. At the end of each marking there is a loop where the larvae turned around and went back along the old track to pick up the new sugar that tree would have sent there to heal itself. Ingenious