caterpillars everywhere!

we've been taken over by caterpillars here. they are EVERYWHERE!!! in some places, they are so bad that farmers are having to spray their fields to keep them from eating all the soybean leaves. other places, so many caterpillars were squished while crossing the road that the highway looks a different color.

at our house, it's not a problem but more of an adventure for raven. she loves to see how many caterpillars she can find and put on herself to come and show me. she's very careful in handling them and then takes them all back outside to the porch/flower garden so they can "go back to their mommies" when she lets them go.

i'm wondering -- what type of caterpillars/butterflies-to-be are these? should i be expecting to be bombarded with a certain type butterfly soon?

also, is there some old folk wisdom, wives' tale, or native/nature relation between how many of these there are compared to what kind of weather we've had or will have?

any help would be appreciated. if anyone wants up-close pictures of some of these to draw, i can send you full-resolution photos from a 7.2 megapixel camera if you want to have big pictures to look at. just send me a request by email and i'll send them to your email.