Europe, Netherlands, City of Amersfoort

I'm a taxonomical entomologist from the Netherlands and I work with all groups of insects and other Arthropoda.
Of special interest to me are the fly families of Syrphidae, Conopidae, Stratiomyidae and some others.
The Syrphidae are my favourite family, I know a lot of the European species and genera.
Of the American Syrphids I can identify the genus in most cases, but I don't know all the American species in these genera!

Greetings,
Gerard Pennards