The ones with blue markings were always called Snake Doctors where I grew up. They always seemed to be flying around in marshy, wet places where snakes were likely to be found, which I assume is where the name came from.
We call the blues ones “mayflies”, because if you go out to any creek in May, there will be a horde of them breeding like crazy.
I grew up in southern Illinois and I recall hearing snake doctor. I haven’t heard that one in so long that I had forgotten about it.