(Caloptilia alchimiella)
Caloptilia alchimiella (commonly known as yellow-triangle slender) is a moth of the family Gracillariidae. It is found in Europe and the Near East. The wingspan is 10–13 millimetres (0.39–0.51 in). Forewings purplish - ferruginous ; dorsum suffused with yellow towards base;a large triangular yellow median costal blotch, apex often rounded. Hindwings dark grey. The moth flies from May to July depending on the location. The larvae feed on Quercus species, Castanea sativa and Fagus sylvatica. Caloptilia is a genus of moths in the family Gracillariidae.