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).

1a > Leaf-miner: Larva mining the narrow branches, not the stem. Pupation external. Puparium brownish-black

On Equisetum arvense in Britain and elsewhere. Uncommon in Britain - Herts and London. Widespread in continental Europe

Liriomyza occipitalis Hendel, 1931 [Diptera: Agromyzidae].

1b > Stem mine.

2

2a > Stem mine: Larva forms an external stem mine which quickly turns black. Pupation internal, puparium projecting out of mine. Puparium dark

On Equisetum fluviatile in Britain and Equisetum arvense and Equisetum fluviatile elsewhere. Widespread in northern Britain - Stafford, Banff, Easterness and Elgin. Widespread in northern Europe. Also recorded in Alaska.

Liriomyza virgo (Zetterstedt, 1838) [Diptera: Agromyzidae].

2b > Stem mine: Larva mining the stem. Pupation external. Puparium brown

On Equisetum arvense and Equisetum fluviatile in Britain and elsewhere. Uncommon in Britain - Herts and Warwick. Also recorded in continental Europe and North America.

Liriomyza equiseti Meijere, 1924 [Diptera: Agromyzidae].