Brood X has peaked, the little red-eyed guys have done what they set out to do, and they are passing away.
“When animals die they have a pretty distinct BAD smell,” wrote Paula Shrewsbury, also a professor of entomology at the University of Maryland, in an email. “As part of the decay process there are a number of interactions between enzymes and microbes that result in the ‘smell of death.’ Cicadas are no different than other animals; when they die they smell bad.”