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

1a > Leaf-miner: A conspicuous blotch, with characteristic greenish diffused frass, several larvae frequently feeding together (Spencer, 1972b: 54).

Primary upper-surface blotch without a trace of a preceding corridor, generally containing several larvae. The mine contains much greenish and half-deliquescent frass. Pupation outside the mine.

Forms an upper surface blotch mine. The mine can contain several larvae.

On Euphorbia in Britain and elsewhere. Apparently widespread in Britain, at least in the south. Widespread in continental Europe

Liriomyza pascuum (Meigen, 1838) [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 including Euphorbia. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

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

1c > Leaf-miner: In the first instar the larva mines the leaves, forming short, irregular, blotch-like mines, but in later instars it lives externally, feeding in spun leaves and often twisting those of tender shoots. Larval head light-brown or yellowish brown, edged with black postero-laterally, ocellar area blackish; prothoracic plate black edged with whitish anteriorly; abdomen dull dark green; pinacula distinct, black, sometimes brownish but with black bases to setae; anal plate large, black (Bradley et al., 1973). Small, full depth mine without a definite shape; little frass. Some silk is deposited in the mine. The larva soon leaves the mine and continues feeding among spun leaves.

Polyphagous. On numerous genera and species of plant families, but not yet on Euphorbia, in Britain. On numerous genera and species of plant families including Euphorbia elsewhere. Widespread in Britain and continental Europe. Also recorded on Channel Is.

Cnephasia incertana (Treitschke, 1835) [Lepidoptera: Tortricidae].