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

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. Probably the larva mines for a few days only, and afterwards lives as a stem borer.

Hosts in Britain unknown. On Elytrigia elsewhere. Added to the British checklist by Henshaw in Chandler, 1998: 137. Widespread in continental Europe including Finland, Poland and Russia (Leningrad area) (Spencer, 1990: 367). Also U.S.A. and Canada (Spencer, 1990: 367).

Cerodontha inconspicua (Malloch, 1913) [Diptera: Agromyzidae]

1# > ? Leaf-miner: Details of mine unknown. Pupation external (Spencer, 1972b: 52). Pupation external.

On Arrhenatherum, Dactylis and Holcus, in Britain and additional grasses elsewhere. Widespread in England and continental Europe.

Liriomyza phryne Hendel, 1931 [Diptera: Agromyzidae].

1a > Leaf miner: Leaf-mine normally short and broad (Spencer, 1976: 97). According to Hering (1957) initially the larva does not feed towards the apex of the leaf. Pupation external (Spencer, 1976: 97).

The shallow, whtish mine starts (not very close to the base of the lamina) as a fine ascending corridor. This is overrun when the direction alternates, and the mine quickly widens. The final mine is characteristically short; often not the full width of the leaf is used. Frass in big black grains, never greenish. Pupation outside the mine.

On Avena, Hordeum and Secale, but not yet on Elytrigia, in Britain and in addition on Elytrigia and Triticum elsewhere. Widespread, but local, in Britain. Common and Widespread in continental Europe. Also recorded in Canada and America.

Agromyza ambigua Fallén, 1823 [Diptera: Agromyzidae].

1b > Leaf-miner: Larvae feeding singly, forming a long, widening mine on the upper surface of the leaf, which is generally limited to one side of the leaf. Pupation external, puparium glued to the leaf near the end of the mine (Spencer, 1976: 128).

Broad corridor, generally beginning near the leaf margin or close to the leaf tip. Most of the times the mine remains at one side of the midrib. The mine is upper-surface, but has some full depth, translucent spots here and there. Frass in rather regularly scattered grains. Pupation outside the mine. According to Dempewolf (2004a) only the male genitalia enable a reliable discrimination from A. abipennis and A. graminicola.

On Glyceria and Holcus, but not yet on Elytrigia, in Britain and additional genera of grasses, including Elytrigia, in continental Europe. Widespread and common in Britain. Widespread in continental Europe. Also recorded in Canada.

Agromyza nigripes Meigen, 1830 [Diptera: Agromyzidae].

1c > Leaf miner: The young larva first feeds towards the apex of the leaf, later turning and feeding downwards. Several larvae can occur together in a single leaf. Pupation external (Spencer, 1976: 130).

Upper-surface, greenish, gradually widening corridor, at first running towards the leaf tip, then reverses. Through fusion of several mines the final mine is often communal. Frass in backish green grains, often washed out. Pupation outside the mine.

Puparium reddish brown

On Arrhenatherum, Dactylis, Elymus, Hordeum, Phalaris, Secale and Triticum, but not yet on Elytrigia, in Britain and additional genera of grasses elsewhere. Widespread in Britain and continental Europe. Also recorded in the East Palaearctic.

Agromyza nigrociliata Hendel, 1931 [Diptera: Agromyzidae].

1d > Leaf-miner: Larvae feed singly, forming greenish mine, initially running towards apex of leaf before turning back down and developing into a broad blotch. Puparium reddish brown.

On Arrhenatherum, Bromus, Calamagrostis, Poa, Secale and Triticum, but not yet on Elytrigia, in Britain and additional grasses elsewhere. Widespread in Britain and continental Europe.

Agromyza rondensis Strobl, 1900 [Diptera: Agromyzidae].

1e > Leaf-miner: Larva feeds mainly in the leaf sheaths. The short mines which may be formed in the leaf blade may be easily overlooked. Pupation internal (Spencer, 1976: 178).

Mine begins as a narrow, usually upper-surface, occasionally lower-surface or interparenchymatous corridor in the blade, that descends towards the ligule, thence continues into the leaf sheath, generally on its inside. Usually only one mine per leaf. Puparium in a puparial chamber at the margin of the leaf sheath. Neither mine nor larva can be distinguished from that of C. fulvipes that, as far as is known, only feeds on Poa trivialis.

On Alopecurus, Elymus, Festuca, Holcus and Phalaris, but not yet on Elytrigia, in Britain (including the Channel Is.) and additional grasses, including Elytrigia, elsewhere. Widespread from the southern England to Scotland, most northerly record Outer Hebrides. Also recorded in the Republic of Ireland, Europe, Africa and Japan.

Cerodontha denticornis (Panzer, 1806) [Diptera: Agromyzidae].

1f > Leaf-miner: A lower surface mine. Pupation normally in the ground (Spencer, 1976: 202).

Broad, usually lower-surface corridor in the blade, generally first rising, then descending. Mostly one larva in a mine, but sometimes several mines on a leaf may merge. Frass in grains that gradually become both larger and more widely spaced. Pupation outside the mine.

On Agrostis, Arrhenatherum, Dactylis, Elymus, Festuca, Holcus and Poa, but not yet on Elytrigia, in Britain. On Elytrigia elsewhere. Widespread in Britain and continental Europe. Also Canada.

Cerodontha flavocingulata (Strobl, 1909) [Diptera: Agromyzidae].

1g > Leaf-miner: Broad elongated mine; the form is dependent of the leaf form of the host plant. Frass green. Usually a number of larvae together in a mine. Pupation in the mine.

On Bromopsis, Dactylis, Elymus and Phalaris, but not yet on Elytrgia, in Britain and additional grasses, including Elytrigia, elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread and common in continental Europe. Also recorded in Japan, U.S.A. and Canada.

Cerodontha incisa (Meigen, 1830) [Diptera: Agromyzidae].

1h > Leaf-miner: A linear mine running towards the apex of the leaf and this can widen and become almost blotch-like. Pupation internal. Puparium brownish-black

On Dactylis, Elymus, Phalaris and Triticum, but not yet on Elytrigia, in Britain and additional genera of grasses, including Elytrigia, in continental Europe. Uncommon in England. Widespread in continental Europe. Also recorded in Japan and Canada.

Cerodontha lateralis (Macquart, 1835) [Diptera: Agromyzidae].

1i > Leaf-miner: Broad lower surface mine which generally starts at the leaf apex.The mine is somewhat irregular in depth. Frass in irregular black-green, frequently melted grains, mostly along the edges of the mine. Larva solitary. Pupation generally internal.

On Calamagrostis, Elymus and Hierochloe, but not yet on Elytrigia, in Britain and additional genera of grasses, including Elytrigia, elsewhere. Widespread and not uncommon in Britain. Widespread in continental Europe. Also recorded Canada and the U.S.A.

Cerodontha muscina (Meigen, 1830) [Diptera: Agromyzidae].

1j > Leaf-miner: Normally several larvae feed together. Pupation in the mine. Puparium shining black (Spencer, 1976: 198).

Broad elongated blotch. Frass greenish. Larvae generally communal. Pupation within the mine. The black puaria are individially anchored within the mine with a silken thread attached at their rear end. Distinguishable from C. incisa only by means of the larva.

On Arrhenatherum, Brachypodium, Bromus, Bromopsis, Calamagrostis, Dactylis, Deschampsia, Elymus, Festuca, Holcus, Lolium, Molinia and Phalaris, but not yet on Elytrigia, in Britain and additional grasses, including Elytrigia, elsewhere. Widespread and common in Britain. Also recorded in the Republic of Ireland. Widespread and frequently common in much of Europe. Also recorded in Alaska and Canada.

Cerodontha pygmaea (Meigen, 1830) [Diptera: Agromyzidae].

1k > Leaf-miner: Upper-surface corridor, generally in the upper half of the blade, running up to the leaf tip, usually occupying more then half the width of the leaf. Frass in green stripes at either side of the corridor. Never more than one larva in a mine. Puparium within the mine, metallic black, not anchered with a string of silk.

On Ammophila and Elymus, but not yet on Elytrigia, in Britain and additional grasses including Elytrigia, elsewhere. Known only from Norfolk and Elgin in Britain. Widespread in continental Europe. Also recorded in Canada and the U.S.A.

Cerodontha superciliosa (Zetterstedt, 1860) [Diptera: Agromyzidae].

1l > Leaf-miner: Long, narrow, whitish mine. Pupation internal (Spencer, 1976: 453); anterior spiracles projecting through the epidermis.

Whitish, upper-surface, rather narrow corridor with comparatively large frass grains that are laying further apart than their diameter. Pupation within the mine. The anterior spiracles of the orange-brown puparium penetrate the epidermis.

On numerous genera of grasses, but not yet on Elytrigia, in Britain. On numerous genera of grasses, including Elytrigia, elsewhere. Widespread and common throughout British Isles and much of continental Europe. Also recorded in Canada, western U.S.A. and Japan.

Chromatomyia nigra (Meigen, 1830) [Diptera: Agromyzidae].

1# > Leaf-miner: Details unknown.Probably the larva mines for a few days only, and afterwards lives as a stem borer.

On Poaceae in Britain, On Bromus, Elytrigia, Hordeum, Melica, Secale and Triticum elswhere. Widespread in Britain and continetal Europe. Also recorded in the Republic of Ireland and Northern Ireland

Ochsenheimeria urella Fischer von Röslerstamm, 1842 [Lepidoptera: Ypsolophidae].

1b > Leaf-miner and Stem-borer: The first instar lave mines in a leaf; after that it lives as a stem borer.

Hosts in Britain unknown. On Elytrigia, Bromus, Bromopsis, PHleum, Poa, Secale and Triticum elsewhere. Widespread in Britain and continental Europe.

Ochsenheimeria vacculella Fischer von Röslerstamm, 1842 [Lepidoptera: Ypsolophidae].