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

1a> Leaf mine: Makes a full depth blotch mine in which the black frass may be visible. May be several mines in the leaf and the larva may exit one leaf and mine in another.

Large, full depth blotch, starting with a short corridor, that often follows the leaf margin. Often 5-12 mines in a leaf. Mines mainly in the lower leaves. The larva may leave its mine and restart elsewhere. Pupation outside the mine.

The larvae of sawflies have at least six thoracic legs (although they may be reduced or absent), a head capsule and chewing mouthparts with opposable mandibles but no abdominal legs.

On Trollius europaeus in Caernarvonshire in Britain and other Trollius spp. in continental Europe.

Pseudodineura enslini (Hering, 1923) [Hymenoptera: Tenthredinidae].

1b > Leaf-miner: Blotch mine tending to fill a lobe of the palmate leaf. Near the beginning of the mine, the frass is concentrated in roughly concentric rings to form a dark spot and elsewhere the frass is arranged in loose series of lines and arcs. Mines often appear rusty and mottled. Larva leaves the mine through the lower surface to pupate externally, presumably in the soil (Bland, Godfray and Henshaw, 1999: 50)

On Trollius europaeus in Britain and continental Europe. Widespread in continental Europe.

Phytomyza trolliivora Hering, 1935 [Diptera: Agromyzidae].

1c> Leaf-miner: Linear mine, possibly forming a secondary blotch.

2

2a > Leaf-miner: Simple white linear mine; frass deposited in scattered black spots. Pupation external (Spencer, 1976: 520).

On Trollius europaeus in Britain and continental Europe. Recorded in Britain from a single male caught in a yellow water trap at Malham Tarn, North York. Widespread in continental Europe.

Phytomyza trollii Hering, 1930 [Diptera: Agromyzidae].

2b > Leaf-miner: Linear mine closely winding; the adjoining sections usually forming a secondary pseudo-blotch; frass variably coloured and in diffuse patches; pupation internal (Spencer, 1976: 522).

On Trollius europaeus in Britain and continental Europe. Known only from Perth in Britain and Germany in continental Europe.

Phytomyza trolliophila Hering, 1949 [Diptera: Agromyzidae].