In cases where the egg is deposited within the plant tissue, this is done either by means of an ovipositor, or by biting a hole in the leaf (mostly a thick vein). This causes a wound reaction of the plant, that may remain long after the mine has been vacated.
Fenusa dohrni: mines, each one with an oviposition scar.
Orchestes fagi, a weevil. A female, that has no ovipositor, gnaws a hole in the underside of the midrib, and deposits an egg in the wound.