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).

# > Details of mine unknown.

Scaptomyza montana of Basden (1954) was misidentified. The true montana (Basden, 1949) (described from North America) was synonymised with flava (Fallén, 1823c) by Hackman (1959), who stated that Basden's montana was an undescribed species. It remains undescribed. (Bachli, pers. comm. in Chandler, 1998: 156).

Scaptomyza sp. [Diptera: Drosophilidae].

1a > Stem mine. An external stem mine. Pupation in the stem, near or even below ground level, with the anterior spiracles projecting through the epidermis. Puparium reddish brown

On Lathyrus, Pisum and Vicia in Britain and Lathyrus and Pisum elsewhere. Widespread in the south of Britain. Widespread in much of Europe.

Ophiomyia orbiculata (Hendel, 1931) [Diptera: Agromyzidae].

1b > Leaf mine.

2

2a > Initially a lower-surface linear mine, which later develops into large whitish blotch which appears like a pale mottled area from above, due to variable depth of feeding through to upper surface. Less frequently feeding in upper surface or stem. Puparium reddish

Part of mine of Agromyza lathyri on Pisum sativum Image: Willem Ellis (Bladmineerders van Europa)

On Lathyrus grandiflorus, Lathyrus latifolius, Lathyrus rotundifolius, Lathyrus tuberosus and Pisum sativum in Britain and additional species and genera of Fabaceae elsewhere. Widespread in southern England - Kent, Surrey, Warwick and Cambridge and Widespread in continental Europe.

Agromyza lathyri Hendel, 1923 [Diptera: Agromyzidae].

2b > Leaf-miner: Mine linear, whitish, both upper and lower surface. Pupation internal, at the end of the mine with the anterior spiracles projecting through the epidermis (Spencer, 1976: 433). Upper-surface, less often lower-surface corridor. Frass in isolated grains. Pupation within the mine, in a, usually lower-surface, pupal chamber (Bladmineerders van Europa). A long whitish upper surface corridor, which eventually goes lower surface (British leafminers).

Two highly polyphagous species of Chromatomyia, with indistinguishable mines, have been recorded in Britain. These are syngenesiae (Hardy) and horticola (Goureau) which can only be distinguished by the male genitalia. Both are polyphagous and widespread in Britain and elsewhere, although syngenesiae is almost entirely restricted to Asteraceae (see also 'atricornis').

Chromatomyia horticola is recorded on 55 plant genera in 19 families in Britain including Pisum in Britain.

Chromatomya syngenesiae is recorded in Britain on 27 plant genera in the family Asteraceae and many more genera elsewhere, but not yet on Pisum in Britain.

Chromatomyia horticola (Goureau, 1851) [Diptera: Agromyzidae].
OR
Chromatomyia syngenesiae Hardy, 1849 [Diptera: Agromyzidae].

2c > An upper surface linear mine with frass in conspicuous greenish strips, largely alternating at each side of the channel. Puparium yellow

On numerous genera of Fabaceae, including Pisum, in Britain and elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland and widespread and common throughout most of Europe

Liriomyza congesta (Becker, 1903) [Diptera: Agromyzidae].

2d > A long linear mine, normally starting on lower surface, frass in black strips alternately at sides of mine.

On Lathryus, Pisum and Vicia in Britain and Lathryus and Pisum elsewhere. Only known from Kent, Surrey, Herts and Warwick in Britain. Widespread in continental Europe.

Liriomyza pisivora Hering, 1957 [Diptera: Agromyzidae].