17-year cicada life cycle, illustration by Patterson Clark






Young cicadas, or nymphs, usually live six to 18 inches underground, sucking sap from tree roots and growing to about 1.5 inches.

As they approach 17 years of age, the nymphs dig a tunnel to the surface with their front legs, creating a small mound of mud — a cicada hut — where they will exit.

When ground temperatures reach 64 degrees, nymphs emerge from their tunnels and climb onto nearby trees, where they shed their skins, or molt.

Adult cicadas, which have orange-ribbed wings and bulging red eyes, live for only four to six weeks. Their goal is to mate and produce eggs. They can fly, but normally don't stray far from where they emerged. The males generate a loud buzz, which atrracts females. Females respond with a flick of their wings.

Female cicadas slice open tree twigs and lay as many as a dozen eggs in single twig. The eggs will remain on the twig for six to 10 weeks before they hatch into tiny nymphs about the size of a grain of rice. The nymphs fall to the ground, dig into the soil and feed for the next 17 years.

17 years already?

Of the 12 broods that show up every 17 years, three appear in this area and only two in large concentrations. Read related article. Broods that emerge in the Washington area:

Broods that emerge in the Washington area

Brood II

Next appearance: 2013
Last seen: 1996

Experts say many places in this area will see fewer cicadas than in 2004, but parts south may get far more.

Brood X

Next appearance: 2021
Last seen: 2004

This brood covers the most territory of the 17-year broods and has by far the largest concentration in this area.

Brood XIV

Next appearance: 2025
Last seen: 2008

Remember the 2008 cicadas? No one does. There weren't enough to make a huge impression here, compared with 2004.