A female Holly blue (Celastrina argiolus) [1] foraging for nectar on Great willowherb (Epilobium hirsutum).

References
1 Nederlands SoortenregisterCelastrina argiolus (Holly blue)♀︎
Epilobium hirsutum (Great willowherb)A female Holly blue (Celastrina argiolus) [1] foraging for nectar on Great willowherb (Epilobium hirsutum).
References
1 Nederlands Soortenregister