I put some insect killer (MERIT) that I got from a "greenskeeper friend" down on both sides of my driveway -?

and about 2 days later I have these "creepy caterpillars all over the concrete drive. They look like "eastern tent worms" and when they die they curl up in a ball. Anyone with a clue to what they are? I searched all over for signs of bag worms in nearby trees and shrubs and couldn't find any - I think these things came out of the ground - what are they - help?