Cicada. Locust. Jar flies. Dry flies. Some common names for the cicada. The cicada is a large noisy insect with big eyes and see through wings. Cicadas are a delicacy...skewered or fried...in some places, but not in my house.
Cicadas drop from twigs as larvae and burrow into the ground where they stay for a while...some 3 years...some 15 years....many different times by different species...but they all know to emerge at the same time. Cicadas leave the empty shell wherever it is attached when they molt...usually a tree...which really look strange just attached here and there by the hundreds. The picture below shows a cicada and the shell it just emerged from.

Cicadas are not pests. They live only a few noisy weeks and die and decompose if the fox and skunks and other insect eaters don't dine on them first.
So why do cicadas all emerge at the same time?

No one is certain. Cicadas have emergent cycles that vary because the cicada is avoiding a frequency that a predator can figure it out and devour the delicious cicada meal. Their internal timing is just so accurate...like over 17 years...that they all tunnel up and out at the same time...is just plain amazing.