Thanks so much for this ID. It is much appreciated.

Thanks so much for identifying these syrphids to species, Martin. I'm delighted to know the species for sure.
No, I do not have the specimen. What seemed strange to me is that one of the abdominal segments is raised. I remember seeing this situation in one of the eumenids where mites lived in the space.

The strange thing is that the antenna is black, while most mexicana I saw had red antennae. Also the thorax is more yellow, while most mexicana have a reddish tone and overall it looks more like a Merodon species (not equestris, one of the mediterranean species), but they are not known from NA... But I am still confident that it is mexicana, just a strange angle ... if I could see the wing venation at the tip of the wing, I could tell... but although the fly is mostly in focus, by chance just the most important details are not visible (wing and hind leg)....
Cheers
Martin