Black-banded Masoner Blastobasis rebeli

An adventive species that has not yet been recorded in Norfolk but is evidently common, locally at least, in Sussex. Previously called Marsh Dowd.

The dark bar about a third of the way down the wings, distinctly broad in some cases, made these moths stand out from the other Blastobasis in the trap. I wasn't entirely sure how diagnostic this feature is so retained three for dissection. Of those two proved to be male rebeli and the third, the individual with the broadest bar across the forewings, was a female which I was unable to determine genitalically. At least two more individuals with similar bars across the forewings were photographed which I assume are the same species.

The shape of the gnathos and also the base of the uncus seem to be relevant to Blastobasis ID, but as they are not in the same plane many photos don't show both clearly. I've included images at different focuses in order to show both here.

male Black-banded Masoner Blastobasis rebeli showing its genitalia including close-ups of its gnathos, uncus, valva and aedeagus, High Hurstwood (East Sussex, UK), 23rd July 2022

different male Black-banded Masoner Blastobasis rebeli showing its genitalia including close-ups of its gnathos, uncus and valva, High Hurstwood (East Sussex, UK), 23rd July 2022

This individual, a female, was also retained, but I didn't make a good job of the dissection and was unable to confirm its identity that way. However it was one of the better-marked individuals so I think the ID is safe without the genitalia.

female Black-banded Masoner Blastobasis rebeli, High Hurstwood (East Sussex, UK), 23rd July 2022

These two were not retained but show a broad dark bar across the wings at one third which seems to be a reliable indicator of rebeli? The first two photos are the same moth and the third is a different moth.

apparent Black-banded Masoners Blastobasis rebeli, High Hurstwood (East Sussex, UK), 23rd July 2022