Key for the identification of the known mines of British
insects (Diptera and non-Diptera) recorded on Marrubium

1a > Leaf-miner and case-bearer: The mines are large and obvious on the upper side of the leaf, betraying the larva or larvae on the lower side. Cases are broad and flat - being very hairy from the texture of the leaf. Immediately after emergence the larva makes a full depth, quickly widening, corridor, with frass as small grains in a broad central band. Finally results in a blotch of 2 x 5 mm, from which the young case is cut. The fully developed case is a hairy, greyish brown to silver grey lobe case case of about 1 cm long, with a clearly laterally compressed end; the mouth angle is about 90°. The case is difficult to separate from that of C. ochripennella.

On Ballota, Lamium, Marrubium and Stachys in Britain and Ballota, Lamiun, Marrubium, Phlomis and Stachys elsewhere. Widespread in England in Britain. Widespread in continental Europe.

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].

1c > 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 Marrubium, 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].

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.