Longitarsus rubiginosus

I found this inside the house and managed to misidentify it as Longitarsus melanocephalus (and posted these photos on my page for that species initially). Later on when I was comparing the spermatheca of another beetle I had identifed as melanocephalus with spermathecae of beetles I'd previously labelled as melancephalus I realised this one was different, having a relatively short rounded apex to the cornu and lacking any hook. That made me suspect I'd gone wrong and in attempting to work out how, I observed that the antennae were paler almost to the tip which they aren't on melanocephalus. No idea why I didn't pick this up when I examined the specimen but I'm now sure it can't be melanocephalus. Fortunately the options for Longitarsus with a long dark sutural stripe and antennae pale to nearly the tip are pretty limited so I think I'm safe to call it rubiginosus.

female Longitarsus rubiginosus showing spermatheca, North Elmham (Norfolk, UK), 29th June 2022