They are of the "crane fly" species.
The one's I referred to last night on chat.
Did the 20 page research paper for Ford on them a few years back.
Know the holding pond at the Flat Rock, Mi plant? They hatch out of there, they need shallow water with a mud bottom. Was eating up new Mazda 6's and Mustang's paint while they set in the storage lot.
Found the problem for them, so now the pond is treated to stop the breeding and hatches.
Hatch, come up, breed and the female goes back down, lays the eggs in the mud then comes up to die with the males.
The one's that cause the worse acid etch damage are the females that didn't breed, and so they land and die out of the water with the eggs still in them. These are loaded with amino acids, protiens, the amino's are the most damaging.
With the right humidity and heat, will eat through a clear/base/primer, right down to the ecoat.
We have them here, only we refer to them as May Flys or Morman Flys. Have several hatches a summer, first one was two weeks ago, the hatches usually end around the end of July, but have seen them in August.
Grumpy