During efforts to generate DNA barcodes for all North European Lepidoptera, Phalonidia manniana (Fischer von
Röslerstamm, 1839) was found to comprise two genetically distinct clusters. Morphological investigation further supports
the existence of two distinct taxa, P. manniana and P. udana Guenée, 1845, sp. rev. Their biologies also differ, P. manniana
feeding in stems of Mentha and Lycopus (Lamiaceae) and P. udana feeding in stems of Lysimachia thyrsiflora and L.
vulgaris (Primulaceae). We provide re-descriptions of both taxa and DNA barcodes for North European Phalonidia and
Gynnidomorpha. Phalonidia tolli Razowski, 1960, syn. nov., is considered a junior synonym of Pudana. Phalonidia udana
is widely distributed in the North Palaearctic, whereas it seems to be rare or missing in large parts of Central Europe. The
study demonstrates the usefulness of DNA barcoding in revealing cryptic species.