Key for the identification of the known mines of British
Diptera recorded on Glechoma

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).

See Key to non-Diptera.

1b > Leaf-miner: A linear-blotch mine, first instar mine is linear, later developing into a conspicuous white blotch. Frass greenish diffused (Spencer, 1972b: 46, 47 (fig. 138); Spencer, 1976: 166).

The mine begins with a long, upper-surface, slender corridor. After a moult the larva changes its behaviour, and makes a large, upper-surface primary blotch without apparent feeding lines. Often the blotch overruns more or less the initial corridor. Frass in the corridor liquified to form a wide green band, with a few tiny black granules along the sides. Pupation outside the mine.

A narrow gallery leading to a largish blotch on the upper surface. Frass is green and indistinct in the gallery - small grains may be seen at the gallery edge.

On numerous genera of Lamiaceae, including Glechoma, in Britain and elsewhere. Widespread and locally common in south of England. Also recorded in the Republic of Ireland and widespread and frequently common in continental Europe.

Amauromyza labiatarum (Hendel, 1920) [Diptera: Agromyzidae].

1c > Leaf-miner: Initially a long, slim corridor, the frass alternating on either the side of the corridor. After moulting, the larva broadens the mine and the frass is less regular. Pupation external.

Hosts in Britain unknown. The record on Glechoma from Warwick (Kingsbury Wood) (Robbins, 1991: 103) is considered unlikely to be correct (Henshaw in Chandler, 1998). On Ajuga, Ballota, Galeopsis, Glechoma, Lamiastrum, Lamium, Leonurus, Marrubium, Mellitis, Mentha, Scutellaria and Stachys elsewhere. Widespread in continental Europe.

Amauromyza lamii (Kaltenbach, 1858) [Diptera: Agromyzidae].

1d > Leaf-miner: An initially linear mine, which at second instar develops into a large whitish blotch with conspicuous black frass. The early linear mine is frequently entirely enveloped by the blotch but is detectable by the alternate irregular strips of frass. Pupation external (Spencer, 1976: 158).

The first part of the mine consists of a long, slender upper-surface corridor. After the first moult this changes into a large primary blotch without feeding lines. Frass in the corridor in short, somewhat angular thread fragments, towards the end even in grains. Frass arranged less closely along the sides than in A. lamii. Pupation outside the mine.

The frass is conspicuous in the mine and the mine is initially linear, then develops into a white blotch, often enveloping this early mine.

On Ajuga, Ballota, Glechoma, Lamium, Marrubium and Stachys in Britain and additional Lamiaceae elsewhere. In southern England and continental Europe.

Amauromyza morionella (Zetterstedt, 1848) [Diptera: Agromyzidae].

Upper-surface, yet rather deep, therefore quite transparent, blotch, always along the leaf margin, generally in the distal half of the leaf. The blotch is preceded by a short and broad corridor, most of the time overrun later. Four to eight larvae may co-occur in a leaf. Pupation outside the mine, exit slit in lower epidermis.

On Glechoma and Lamium in Britain and Lamium and Lamiastrum elsewhere. Uncommon in Britain - Bucks, Surrey, Warwick, Cambridge and Middlesex. Widespread in continental Europe.

Agromyza flavipennis Hendel, 1920 [Diptera: Agromyzidae].

1f > Leaf-miner: A distinctive mine with a short linear section at the beginning, then winding and forming a secondary blotch and finally a short straighter end section. Pupation internal or more normally the puparium falls to the ground (Spencer, 1972b: 96 (fig. 96), 97; Spencer, 1976: 324 (fig. 738).

The mine begins as a narrow corridor, with the frass in fine grains along the sides. In the next section the corridor is much wider and more closely wound, forming a secondary blotch; the frass now forms pearl chains. In the final section the corridor is again narrower, rather straight and especially interparenchymatous, greenish in transparency. Pupation outside the mine, but the puparium often sticks to the leaf.

A short upper surface gallery, then winding to form a blotch; finally becoming linear again- the last section being shallow and looking green.

On Glechoma in Britain and elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland and Widespread in western and central Europe.

Phytomyza glechomae Kaltenbach, 1862 [Diptera: Agromyzidae].