Chrysalis's found in a group of mud cocoons

[Ferityelf]

I am in the Limousin, France and have found a group of mud cocoons in my house, Inside the cocoons are long thin chrysalis, they were empty, Last year I found something similar inside my chimney lining, these contained tiny bright yellow/green spiders, not sure if they are the same as there were no chrysalis in last years. I have some pictures of the recent find and will load them up asap. Does anyone have any idea what they may have been? What ever this years find was, they must have been very small to get in and out of the place I found them.

[eucera]

These sound like nest cells of a wasp in the genus Sceliphron. There are 4 species in France, and the Limousin would be at the northern limit of their ranges.