A rare blue-eyed cicada was found in Niles. But thousands more could exist, professor says.

Carole Will McDonald didn’t think she would find a blue-eyed cicada when she went looking for one in her front yard in Niles. It was a one-in-a-million shot, she understood, to find one amidst its red-eyed brethren  in a sea of cicadas that have taken over the northern suburbs with their signature singing and clumsy flying.

“It was pretty cool… I mean, he did stand out from the others,” McDonald recalled thinking when she first saw it. After taking a picture of the statistical anomaly...