Ophion brocki

I initially tried using Gavin Broad's key to nocturnal Ichneumonidae to identify this and arrived fairly comfortably at Ophion costatus, a species I didn't think I had identified before. As something new I thought I'd best check against the review of the Swedish Ophion by Johansson and Cederberg but before doing so I had a quick look at Twitter (X) to see if it's a species Andy Mus or Gavin Broad have tweeted about. The most recent post mentioning it was from Gavin responding to an ID request: "Probably one of the newly described species (brocki or splendens) that used to be known as costatus." Clearly I did need to check the Swedish review - brocki and splendens were first described there so Gavin's key had not included them. Sure enough, the Swedish review key took me straight to Ophion brocki and another quick search on Twitter confirmed that Andy has had several so presumably not uncommon.

My specimen had 60 flagellomeres on each antenna and, although it's not apparent in the live photos and I don't remember noticing it when the insect was alive, the wings (in death at least) have a distinct yellow suffusion. There is a slight difference between the diagram of the propodeum in the Swedish paper and my specimen, in that the diagram shows the central longitudinal carinae broken in the middle - they were complete on mine.

Ophion brocki showing face and mandibles, base of antennae, head from above, head from behind (2 views), epicnemial carina, propodeum, hind femur, first abdominal segment (with close-up of spiracle) and hindwing bases (2 photos to show nervellus in each, with close-up of one), North Elmham (Norfolk, UK), 30th April 2023