Photographed very recently near a river in Zhejiang China. It looks to me like a Sarco but I wasn't able to find a genus that has similar venation. Or is it not a Sarco? Thanks!
Great! Thank you, Theo, for confirming the family! This Sarco has its vein M1+2 bending and reaching vein R4+5 instead of wing margin. This seems to rule out a lot of genera.