They're a type of mite, the larvae of which has 6 legs but is near-microscopically tiny, that likes to munch on the skin cells of animals (including us) & leave tiny but maddeningly itchy bumps (papules), hives or rashes. You're far enough north not to have any, but they're widespread in forest & grassland areas of the warm-damp southeast & midwest, also Mexico. The U.K. has a "relative" that is found from western Europe to eastern Asia. You learn quickly not to sit in the grass in areas where there are chiggers, but usually they bite ankles, generously leaving your upper body to the mosquitoes.
Thank you for the insight!!!
I can't believe I've never at least heard of them in my 41 years!!