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

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.

1# > ? Leaf-miner: Details of mine unknown.

On Solidago in Britain. On Anaphalis, Arnica, Aster, Erigeron, Petasites and Solidago elsewhere. Only known from Aberdeen in Britain. Only known from Sweden and possibly Germany in continental Europe.

Pegomya depressiventris (Zetterstedt, 1845) [Diptera: Anthomyiidae]

1a > Stem-miner: External stem-miner (Spencer, 1972b: 61).

On Sonchus oleraceus, but not yet on Solidago, in Britain. On Crepis, Lapsana and Sonchus elsewhere. Uncommon, but locally abundant in Britain including London, Essex and Hunts. Widespread in continental Europe. Also recorded in Brazil, Canada, and the Afro-tropical, Australian, East Palaearctic and Oriental regions.

Phytoliriomyza arctica (Lundbeck, 1901) [Diptera: Agromyzidae].

1a >Stem-miner: A narrow, inconspicuous stem mine. Pupation at the end of the mine (Spencer, 1976: 64).

Fine, upper- or lower-surface corridor, ending in a thick vein. From there the mine extends finally to the rind of the stem. There also the pupation takes place, usually not far from the root collar. Mines in the stem rind often are conspicuous through a red discoloration.

On Achillea, Achillea millefolium and possibly Anthemis, Matricaria and Medicago sativa in Britain. In Britain widespread in south, not uncommon. On Anthemis, Achillea, Artemisia, Aster, Centaurea, Clinopodium, Crepis, Hieracium, Matricaria, Reichardia, Solidago, Tanacetum, Tripleurospermum, Medicago, Satureja and Stachys elsewhere. Widespread in continental Europe.

Ophiomyia curvipalpis (Zetterstedt, 1848) [Diptera: Agromyzidae].

1b > Leaf-miner: A distinctive mine primarily above mid-rib, with irregular short lateral offshoots into leaf blade. Pupation external (Spencer, 1972: 51 (fig. 172), 55; Spencer, 1976: 270, 271 (fig. 486)).

Branched, whitish, upper-surface corridor; main axis overlying the midrib; side branches overlying the main lateral veins. (In Campanula and Phyteuma the mine is much less branched, sometimes nothing more than a corridor on top of the midrib). Frass in rather long strings. Usually the mines begins as a long and narrow, shallow, tortuous lower-surface corridor that ends upon the midrib but otherwise is not associated with the leaf venation. Often this initial corridor is filled with callus, and then even less conspicuous. Pupation outside the mine.

A linear mine on the upper surface, usually following the midrib and showing side branches along the veins. The frass is in strings.

Polyphagous. On more than 40 host genera in 15 families in Britain includng Solidago. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Liriomyza strigata (Meigen, 1830) [Diptera: Agromyzidae].

1c > Leaf-miner: Mine not primarily associated with the mid-rib.

2

2a > Leaf-miner: A linear mine commencing with a conspicuous regular spiral and then continuing a considerable distance more or less straight (Spencer, 1976: 245).

Upper-surface corridor. The first part is wound in a dense spiral that quickly turns brown. The spiral continues in a long, generally unbranched corridor that maintains almost the same width. Frass in long thick strings. When the mine is positioned near the leaf margin the spiral part may be missing; the thick frass strings then are sufficiently characteristic. Pupation outside the mine; exit slit in lower epidermis.

Long upper surface gallery starting with a spiral of 6 to 8 turns (as shown). Frass in conspicuous narrow linear lines.

On Aster, Eupatorium, Helianthus, Lapsana and Solidago [Asteraceae] and Galeopsis [Lamiaceae] in Britain and continental Europe. Widespread in England. Also recorded in the Republic of Ireland. Widespread in continental Europe and recorded in Canada.

Liriomyza eupatorii (Kaltenbach, 1873) [Diptera: Agromyzidae].

2b > Leaf-miner: An irregular linear mine, which in small leaves can form a secondary blotch.

Long, upper-surface corridor, winding through the leaf and frequently crossing itself; in small leaves often a secondary blotch in the end. Frass in short strings and pearl chains. Pupation outside the mine.

An irregular gallery, sometimes crossing over, with black frass arranged as elongate very narrow streaks at the sides of the mine.

On Aster, Bellis and Solidago in Britain and additional genera of Asteraceae elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread and common in much of continental Europe.

Liriomyza pusilla (Meigen, 1830) [Diptera: Agromyzidae].

2c > Leaf-miner: Broad corridor overlying the midrib. The mine has a number of side branches that distally widen strongly, and may coalesce. Primary and secondary feeding lines very conspicuous. Pupation external, in soil.

On Aster and Solidago in Britain and possibly also Cirsium elsewhere. In Britain Recently recorded only from Kent and Perth. There are old records (pre-1960) for Hereford and Lancaster.

Cornutrypeta spinifrons (Schroeder, 1913) [Diptera: Tephritidae].

2d > Leaf-miner: A large, brownish blotch, with conspicuous feeding lines. Pupation external (Spencer, 1972b: 62 (fig. 205), 63; Spencer, 1976: 308, 309 (fig. 557)).

Large, brown, upper-surface blotch with conspicuous primary and secondary feeding lines. The feeding lines are the more apparent because the semiliquid frass adheres to them. Pupation outside the mine; exit slit in the upper epidermis.

A short broad gallery, normally at the margin, leading to a blotch with obvious feeding lines in whorls. Mines go brown.

On Solidago canadensis and Solidago virgaurea in Britain. On Aster, Baccharis, Buphthalum, Erectites and Soligago elsewhere.

Nemorimyza posticata (Meigen, 1830) [Diptera: Agromyzidae].

2e > Leaf-miner: A long, winding leaf-mine on the upper surface of the leaf, with frass widely-spaced in conspicuous black lumps. Pupation internal, at the end of mine (Spencer, 1972b: 28 (fig. 68), 29).

On Solidago in Britain. On Aster, Callistephus, Erigeron, Sonchus, Solidago and Taraxacum elsewhere. Only recorded from Kent, Derby, Warwick and East Kent in Britain. Widespread in much of Europe. Also recorded in Japan, Canada and the U.S.A.

Ophiomyia maura (Meigen, 1838) [Diptera: Agromyzidae].

2g > Leaf-miner: A conspicuous white mine with frass in more or less connected strips, older mines can show a conspicuous reddish-violet discolouration (Spencer, 1972b: 76 (fig. 253), 80; Spencer, 1976: 501).

Upper surface corridor, 6-9 cm in length, densely wound, easily confluent into a secondary blotch. Frass unusual, in more or less connected strings at either side of the corridor. Pupation outside the mine, exit slit usually in the upper epidermis. According to Hering dried mines turn yellow brown to reddish purple.

On Solidago virgaurea in Britain and elsewhere. Probably widespread in Britain. Widespread in continental Europe.

Phytomyza solidaginis Hendel, 1920 [Diptera: Agromyzidae].

2h > Leaf-miner: A whitish linear mine, with frass predominantly in separate grains, rather than connected strips (Spencer, 1976: 525).

Initially narrow, gradually and weakly widening corridor of about 10-12 cm. The mine is upper-surface, pale green. Feeding lines not conspicuous. Frass in separate grains or short pearl chains. Pupation outside the mine, exit slit in lower epidermis.

On Solidago virgaurea in Britain and elsewhere. Also on Bellis perennis elsewhere. Only known from Surrey in Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Phytomyza virgaureae Hering, 1826 [Diptera: Agromyzidae].

On Aster and Solidago in Britain and elsewhere. Rarely found in the the UK. Recorded from Somerset, Oxford, Suffolk and Cambridge and West Kent. Also recorded in continental Europe.

Pegomya nigrisquama (Stein, 1888) [Diptera: Anthomyiidae].

2j > Leaf-miner: A short linear mine in first instar, later producing a circular or oval blotch. Frass is excreted in a black mass prior to pupation; puparium firmly glued with frass within the mine (Spencer, 1976: 306).

Large, whitish, upper-surface blotch, preceded by a short corridor that often is overrun later by the developing blotch. The larva hardly produces any frass; the few grains that are present are black and rather coarse. But when the larva is about to pupate, it empties its intestine, which has the effect that the puparium is anchored in the mine by dried frass.

The initial gallery by the first instar larva then leads to a whitish blotch. The puparium is fixed to the inside of the mine by an accumulation of frass.

On Aster, Bellis and Erigeron, but not yet on Solidago, in Britain and additional genera of Asteraceae elsewhere. Widespread in southern England and continental Europe. Also recorded in Canada, Argentina, South Africa, India, Australia and Papua New Guinea.

Calycomyza humeralis (von Roser, 1840) [Diptera: Agromyzidae].