Is this an Endothenia sp?

[MPStanyer]

I think this moth, trapped on 8th September is one of the Endothenia sp. I suspect it is most likely marginana but I'm not sure whether the id can be confirmed without details of the hindwing. Does anyone know if this can identified to species based on the available images?

Endothenia sp Marple 8th Sept 2021

Endothenia sp Marple 8th Sept 2021

Endothenia sp (underside) Marple 8th Sept 2021

Thanks,
Martyn S.

[GasMacc1]

The standard wording in more than one text book is:

"Males can be easily distinguished from both sexes of E. gentianaeana and E. oblongana by their white hindwings. Both sexes can be seperated from E. gentianaeana by the narrower area of whitish ground colour distad of the median fascia. Some specimens, especially females, may need retaining".

That would seem to suggest that a hindwing check would be required, but would only lead to a confirmed ID if the specimen was male. If your moth was female, you could use the photos to separate from E. gentianeana, but not from E. oblongana.

Previous records of E. marginana in Cheshire have either been supported by a hindwing check or by gen. det.

[MPStanyer]

Thanks for the the detailed and helpful response. I subsequently checked the hind-wing which was unfortunately not white, rather dark brownish grey but paler grey towards the base. having no experience of the genus I am not sure I can even discount E. gentianaeana although the images I have seen do seem to show more white on the outer wing than my specimen. Sterling & Parsons also imply a September moth is more likely to be an oblongana/marginana. I guess I'll have to record this as an Endothenia sp. At least I got the genus right (hopefully?)
Thanks again.
Martyn.