E. M. Laasonen & L. Laasonen: Habitual differences of Phyllonorycter salictella (Zeller, 1846) and P. heringiella (Gronlien, 1932) (Lepidoptera : Gracillariidae) in two Finnish materials; a problem pair. - Entomologica Fennica 11: 175-181.
From Phyllonorycter salictella (Zeller,1846) a sister species P. heringiella (Gronlien, 1932) is here extracted on the basis of the number and colour of costal strigulae at the tip of the wing and the brightness of the golden coloration of the forewing. P. salictella is reported from the Finnish biogeographical provinces Ab Ab, N, Ka, Ta, Kl, Oa, Tb, Om, Oba, and Obb and P. heringiella from AL Ab, N, Ka, Ta, Sa, and Oba. It is assumed that the golden hue, which sometimes covers the normally white strigulae of the forewing, occurs in freshly emerged moths and disappears after first flying efforts.