We definitely have them in Connecticut, and they are part of the same 17 year cycle. I believe the same insect and hatch occurs from CT to the midwest and beyond (Kansas). There are other cicadas with slightly different emergence cycles and periods. Every summer in August, there are huge numbers of cicadas around my home. They emerge from the ground, climb my trees, split open their exoskeleton and fly away. They are big stocky insects and fly erratically, landing in the tops of trees and calling (chirping) constantly.

As far as there importance for the CT trout fisherman, I don't know.