Note: Diptera larvae may live in a corridor mine, a corridor-blotch mine, or a blotch mine, but never in a case, a rolled or folded leaf, a tentiform mine or sandwiched between two more or less circular leaf sections in later instars. Pupation never in a cocoon. All mining Diptera larvae are leg-less maggots without a head capsule (see examples). They never have thoracic or abdominal legs. They do not have chewing mouthparts, although they do have a characteristic cephalo-pharyngeal skeleton (see examples), usually visible internally through the body wall. The larvae lie on their sides within the mine and use their pick-like mouthparts to feed on plant tissue. In some corridor miners frass may lie in two rows on alternate sides of the mine. In order to vacate the mine the fully grown larva cuts an exit slit, which is usually semi-circular (see Liriomyza huidobrensis video). The pupa is formed within the hardened last larval skin or puparium and as a result sheaths enclosing head appendages, wings and legs are not visible externally (see examples).

1 > Leaf-mine. Oviposition takes place at the base of the petiole in a young leaf. Larva initially feeds in mid-rib, later producing characteristic irregular upper surface linear-blotch. Pupation internal.

On Ilex aquifolium in Britain and elsewhere. Widespread throughout Britain. Also recorded in the Republic of Ireland. Common and Widespread in continental Europe. Introduced into western Canada and the north-west U.S.A.

Phytomyza ilicis Curtis, 1846 [Diptera: Agromyzidae].