CHICAGO — Billions of cicadas are expected to emerge this month in parts of the Midwest after spending 17 years underground. The red-eyed, shrimp-sized, flying insects don’t bite or sting. But they are known for mating calls that produce a din that can overpower ringing telephones, lawn mowers, and power tools.

The plague is expected across northern Illinois, and in parts of Iowa, Wisconsin, Michigan, and Indiana. Cicadas live only about 30 days as adults, and their main goal is mating.

They don’t harm humans, although they are clumsy and might fly into people. Birds, squirrels, and pets, especially dogs, love to eat them, and they are high in protein.

“They’re going to have quite a meal. It’s going to be like Thanksgiving for them,” a supervisor for plant health care at the Chicago Botanic Garden, Tom Tiddens, said.

They are periodical cicadas, which are only found in the eastern half of North America. The annual, or dog-day cicadas, that appear every summer are common around the world.

The last massive emergence of periodical cicadas was in 2004, when the creatures emerged after 17 years underground in parts of 15 Eastern states. Some broods emerge after 13 years.

A single male’s shrill courtship call can reach 90 decibels, equivalent to a kitchen blender. A 103-year-old music festival held north of Chicago, Ravinia Festival, revised its schedule to avoid classical musicians having to compete with the insects, the festival president and CEO, Welz Kauffman, said.