The eggs of the Scribbly Gum Moth (Ogmograptis scribula) are laid between the old and new season's bark of eucalypt trees. As the larva burrows between the bark layers it leaves a tunnel which is revealed when the old bark falls away. Like all insect larvae, that of Ogmograptis scribula increases in size periodically and these changes can be seen as a widening in the tunnel revealed as a scar on the bark surface.