Ceutorhynchus alliariae

I swept this from Garlic Mustard. I recognised it as being Ceutorhynchus but went back to check this after failing to key it to species. Once back in the right genus I still couldn't get it to key out correctly so resorted to picture-matching at various websites. The first one I came across that matched both reddish tarsi and lack of patches of scales on the elytra was alliariae so I checked the keys to see where I had elimated this. I had looked for any sign of teeth or appendiculations on the tarsal claws and failed to find any, and this, it turned out, was where I went wrong. If I took the claws to have basal teeth then both keys led to alliariae. But even under high magnification I struggled to see that the claws were toothed. After a lot of searching I could make out what could potentially have been the expanded base of the claw, but I wasn't convinced that I was looking at the base of the claw and not the tip of the onychium - in fact it looked to me more like the latter, which I think is why I hadn't seen it before. I decided to soak the claw in KOH to see if that cleared things up, and indeed it did - it wasn't part of the onychium, it was the base of the claw, and it was toothed (well, I always think "tooth" is a stretch for the gentle bulge that is often enough to qualify a claw as being "toothed").

Ceutorhynchus typhae showing dip behind front of pronotum, close-up of elytra, side of pronotum, side view of foreparts, hind tarsal claw before clearing and hind tarsal claw after clearing, Wendling Beck Environment Project (Norfolk, UK), 17th April 2025