A double brood of cicadas to emerge this summer

[Catherine]

Cicadas are an interesting insect. They emerge as adults briefly. The rest of their time is spend underground in the nymph state.
The time they spend underground varies with the exact species. One group that emerges every 17 years, will emerge this year.
Another group that emerges every 13 years will also emerge. This double brood emergence last happened 221 years ago. 
The sky will be thick with Cicadas in 17 American states.


https://www.cbc.ca/radio/asithappens/cic...-1.7167254

This is an interesting phenomena.  We forget about cicadas sometimes because we don't see them for years, then suddenly they are everywhere.
It would be interesting to go see them. Nature is full of surprises and events. You do have to wonder why they spend so much time underground.