Reply #16: They are very small, half a grain of rice, they get on you and instantly bite, then others join in.

[dixiegrrrrl]

The bite injects acid. Feels like a small bee sting, then the next day a blister forms, itches like hell, after awhile the blister goes away and leaves a permanent round red mark. I have marks that are 10 years old.
They swarm immediately if anything touches their nest mound, but they have underground tunnels under the mounds.
Nasty things.