The adult is harmless and feeds on nector. Children and I like to play with them

. It makes a long sawing day shorter.
The Larvae are Wire Worms. The orange(ish) colored hard skinned worm you see in rotted wood or just under the bark of a log that has been down a pretty good while. I've seen them in compost piles.
The book indicates a real problem with corn.
They are responsible for root damage in many plants.