Confidence: It's likely to be this, but I can't be certain.
Notes: Superficially similar to Ephialtes but the median lobe of the mesoscutum protrudes anteriorly, and the apical tergite is pointed. If I squint I can see a hint of transverse carinae on the mesoscutum. Subfamily Rhyssinae. Smaller cousin of Ryssa persuasoria but without the yellow spots. A parasite of the alder woodwasp.