Scientists search for the mysterious cause, as millions of hatching bugs loudly buzz the night away Swarms of cicadas are unexpectedly crawling out from under trees from North Carolina to New Jersey. The red-eyed insects are almost impossible to miss; they fly around lazily, plunking into backyard barbeques and crashing into cars. They litter the ground with their crunchy husks as they molt. Most noticeably, they chirp en masse for their mates, producing a relentless, shrill buzz that is recognized as a song of summer. And within a month they are gone. Different populations, or broods, of "periodical" cicadas emerge in distinct geographical regions during specific years, after spending a 13- or 17-year span growing underground. (Some "annual" species just emerge yearly.) Scientists were expecting to see Brood VI bugs in South Carolina and Georgia, which happened, but they got a surprise when Brood X cicadas also started appearing in North Carolina, Virginia, Maryland, the District of