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

1a > Leaf-miner: Larvae usually feed on the underside of a fern frond under an untidy mass of sporangia, but on occasion enter the leaf to make an extensive irregular blotch mine. Usually the larva lives free under the leaf, under an inrregular mass of spun soredia and frass. The larva feeds on the sori, and larva betrays its presence as a sorus on an unusual place. Sometimes also elongate full depth blotches are made.

On Asplenium, Phyllitis, Polystichum and Dryopteris in Britain and Asplenium, Ceterach, Phyllitis, Polystichum and Dryopteris elsewhere. Widespread in southern England and Wales. Initially occurred mainly near coasts, but it is increasingly recorded inland. Outside of Britain and Northern Ireland, only recorded in Madeira.

Psychoides filicivora (Meyrick, 1937) [Lepidoptera: Tineidae].

1b > Leaf-miner: Full-depth corridor or blotch, often positioned along the leaf margin. In the first part much, brown-black, fine-grained frass, later parts of the mine almost free from frass. After hibernation the larva lives free in an untidy case of silk, covered with remants of sori.

On Asplenium, Ceterach, Phyllitis and Polystichum in Britain and Asplenium, Ceterach, Phyllitis, Pteridium and Dryopteris elsewhere. Widespread in Britain and continental Europe.

1c > Leaf-miner: Larva forms a long greenish linear mine, frequently following a vein; mines can be up to 10 cm long. Pupation internal; anterior spiracles projecting through the leaf epidermis (Spencer, 1972b).

Corridor, with the frass in an almost uninterrupted line along one side. In small leaves the corridor often follows the margin, but when space is not limited, like in Hart's-tongue Fern, it curves smoothly, not infrequently running over the midrib for some distance. Pupation mostly within the mine; the anterior spiracles then penetrate the epidermis.

Forms a long narrow mine (up to 10cms). It is normally greenish and upper surface.

On Asplenium ruta-muraria, Ceterach, Phyllitis scolopendrium and Polypodium vulgare in Britain and in addition to these Asplenium scolopendrium and Asplenium septentrionale and Ceterach officinarum elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread in much of Europe.

Chromatomyia scolopendri (Robineau-Desvoidy, 1851) [Diptera: Agromyzidae].