Here are two size classes of Pteronarcys
nymphs. These probably represent two different generations. The largest will probably emerge next spring and the other in two years. There is probably another generation, smaller, I did not collect. In a Canadian study they discovered Pteronarcys
eggs do not all hatch simultaneously but hatch for a period of nearly two years, making their egg/nymphal life 5 years. The other photo is of a curled nymph, a typical response to disturbance.