The second and third cases are cut out of a mine along the leaf margin.
The section before the turn often follows the leaf margin.
The corridor often follows the leaf margin for some time.
The mine starts as a fine corridor, often following the leaf margin.
The mine starts as a short corridor close to the leaf margin.
The first one third is particularly narrow and closely follows the leaf margin.
The last part of the corridor often follows the leaf margin for some distance.
The corridor usually follows the leaf margin for a long distance.
The leaf margin is always entire, but in some species and forms can be rather wavy.
The corridor generally follows the leaf margin over a long distance.