#4
I can not place this in the key to Chinese Mydaeinae (Xue and Tian, 2014).
Only two species of
Mydaea have 3 post dc and yellow femora. One of them has a black basicosta, the other has a long prealar and a posteroventral bristle on the fore tibia. The key is for males, but these are not usually sexually dimorphic characters.
https://academic.oup.com/jinsectscience/article/14/1/22/2385619