Dolerus pratensis

The description of the scutellum in the RES key is problematic in my opinion, and at least two of the pratensis that I've found seemed to me to fit the description for bimaculatus better in regard to the puncturing on the scutellum. However the large size should ring alarm bells if, like I did with this one, you end up keying it to bimaculatus. For males, the penis valve should settle matters if in any doubt.

male Dolerus pratensis showing abdominal sculpture, scutellum and penis valve, Rush Meadows (Norfolk, UK), 18th May 2026

This was found at a small newly-created fen.

male Dolerus pratensis showing its forewing (top lit and backlit), hindwing, scutellum and mesonotal lobes, abdomen (segments 1-2 and 2-4) and penis valve, Wendling Beck Project (Norfolk, UK), 14th May 2022

This one was found in exactly the same place. I keyed it using the RES key but the scutellum/pronotum puncturing wasn't as described there. The penis valve removed any doubt.

male Dolerus pratensis showing its forewing (top lit and backlit), tergites (with close-up), pronotum from above/rear and penis valve, Wendling Beck Project (Norfolk, UK), 10th May 2024