Stigmella salicis

Wingspan 4 to 6 mm. The adults have dark forewings with a purplish sheen and an irregular yellowish fascia. The cilia are noticeably pale and the head is orange. The larva mines the leaves of coarse leaved willows such as Goat Willow and Grey Willow. The mine is usually short and broad with a thick dark frass-line. It is very variable - ranging from a contorted gallery to a short angular gallery that looks more like a blotch; egg position also varies between upper and lower surfaces. Photograph the mine with backlight; note host species or species group (e.g. 'Sallows') and if possible note egg position. The egg is a small shiny speck which can be hard to find on the leaf under-surface; it is often in a leaf axil or by a vein but may be hidden close up against the midrib and buried under the wooly leaf surface. On the wing in April and May and again in July and August. Larvae feed on sallow (Salix spp.). The mines can be found in June and July and from September into November. Widespread and fairly frequent in Britain. In the Butterfly Conservation's Microlepidoptera Report 2011 this species was classified as common. DNA analysis has revelaed a complex of species, of which 2 (as yet un-named) are found in the British Isles. Further research is needed, but egg position and apperance of larva may be critical in separating out the species complex. See Edmunds, R. (2017) The Stigmella salicis complex . Leafmines Newsletter 34 4. http://www.leafmines.co.uk/pdfs/newsletter34.pdf http://www.leafmines.co.uk/html/Lepidoptera/S.salicis.htm https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/lepidoptera/monotrysia/nepticuloidea/nepticulidae/stigmella/stigmella-salicis/