#1
Systoechus or Bombylius?
I have a key, but i can understand what's the different :/...
Poland, Mazovian Voivodeship, 08.06.2017.
#3
It is about the relative length of two wingcells br and bm (br longer than bm in Bombylius - br equally long like bm in Systoechus)
for pics try
for Bombylius http://drawwing.org/insect/bombylius-major-wing-0
compare for Systoechus fig b in https://biologicalsurvey.ca/ejournal/kme_06/images/figure_61.jpg
so yours is a Bombylius