I was there again to days ago, and saw atleast one of the two females from last time. I was trying to find out which species it uses as host in Sweden. I dont think it is known, I checked your database and the two listed host species do not occur in Sweden:
Halictus maculatus
Eumenes pomiformis
Do you have any hunch of what host it might have? Someone I talked to over the internet mentioned Megachile dorsalis?
C. scutellaris is found only on a hot, sandy place in Sweden, a place with many other rare Hymenopterans. I saw one female C. scutellaris crawl down a hole at the base of a small tuft of grass (Corynephorus canescens ), and she was there for some time, so I guess she could have oviposited? The whole was going into the ground at a shallow angle, from what could be seen. I waited at the hole for an hour or so, but the owner did not come back :/
I also noted one female
completely burrowing herself into the sandy ground, it took several minutes for her, unfortunately I went for my camera and when I got back I couldnt find the spot again
/Alex