#1
I suppose this is a
C. relictus female with reduced marking on Tergit 2, and not
C. viduatus?
13.07.2020, extensively managed wet meadowland, Lüchow-Dannenberg,Niedersachsen, Germany.
#3
I've checked many
Chrysops and photographed them while they were sucking my blood, and again and again it was
relictus, so maybe I've given up hope to find another species of this genus

And in your book it reads "Donkere Vlek op tweede rugplaatje breed U-vormig (van achteren niet ingekeept)", maybe I misinterpreted that.
Many thanks anyway
Jann