General comments:
Most species of Parnornix can be named reliably from their larval mines but in cases of difficulty the adults should be reared through for examination.

Separation of the blackthorn-feeding Parornix is often difficult, but rearing adults from collected mines seems to suggest that finitimella is far more frequent than Deltaornix torquillella in both Hertfordshire and Middlesex. This is at striking odds with the results for wild-caught, free-flying adults; dissection suggests that torquillella is far and away the more numerous. Clearly, there is scope for some research in this area.

	Determination by Genitalia Examination Required

	Mine: Either the leaf or a good photograph required

Recorded in 28 (68%) of 41 10k Squares.
First Recorded in 1890.
Last Recorded in 2023.