#2
I am afraid this is not
Tolmerus atricapillus. Ovipositor, legs and mystax are wrong for this species. But I cannot help much either as there are too many Italian species unknown to me

Perhaps somebody can recognize it though. Please, wait for other opinions

#4
Thanks Alvarez and Reinoud!
I have to check, maybe I still have the specimen.
Thanks for the help!
Marcello