Last april Arno van Stipdonk and I found some Chrysura specimens on a Dutch limestone grassland. They were inspecting snail shells that were also visited by Osmia aurulenta. We concluded that it had to be C. trimaculata, the 'normal' Osmia aurulenta Chrysura in adjacent areas. Only later we found out that C. rufiventris is expanding its range and recently found in northern France and nearby Germany.
As C. trimaculata has never been recorded in the Netherlands (nor has rufiventris) we only collected a male. Unfortunately we can't find any descriptions to distinguish between males of both species. Is such literature available?
Or is it possible to ID our (rather poor) pictures?
The first 2 concern a female (photo A. van Stipdonk); not very trimaculata like because T3 is not flat and rather strongly pitted but also different from the drawings by Berland & Bernard, 1938.
The last 2 concern the collected male.
Kind regards,
Ivo Raemakers.