This Potter wasp male Eumenes coronatus  visited two nectar sources in the garden for about a week, one being the GIant goldenrod (Solidago gigantea). It is a rare wasp in the Netherlands .
He is the first of its genus and species visiting the garden, a new garden species!
The wasps in this genus are delicate looking, nicely designed wasps. Hopefully some day the females will find the garden as well and built their urn shaped nests.
I caught him for identification.
References1 Nederlands Soortenregister