Randolph set down his magnifying glass and closed his eyes. How could this be? The timing of all of the other broods had matched the predictions exactly. Even the geographic distribution had been spot on. And yet there on his desk sat living refutation of all of his work. Cicadas simply didn’t work this way – singletons didn't survive. And this cicada had been one of thousands reported throughout Central Park. In the middle of October, no less.
He flipped back through the logs. Even something as basic as the temperature didn’t make any sense. The soil was too cold for nymphs to become active. Even if there was a brood that was completely out of synch with the rest, it shouldn't--
He sat back suddenly. Hard data on the eastern broods went back about a hundred years. Anecdotal evidence from newspapers and almanacs was good for fifty more. What if he went farther back? What was it Balachandran had said about temperature cycles at the Ipswich conference? He'd been going on about periodicity in the Little Ice Age, but the time scales were way outside of the range of cicada dormancy.
He brought Balachandran's paper up on his screen. Figure 12 was fairly compelling – major and minor sets of temperature oscillations, quite regular. The minor sets came just over a century apart, with the major swing happening about every 660 years. That put the next big dip at about the present day. Of course, that could be offset by the radical change in atmospheric concentrations of carbon dioxide over the past hundred years. But adjusting for that, late springtime temperatures during the dip would be most closely approximated by the temperatures of . . . October. October of 2015 would feel very much like May of 1350. That would be a long dormancy indeed. Interesting.
Out of curiosity, he pulled up a page on global history during the 14th century. Not much in the Americas, but Europe was another story altogether. What would the geographic distribution of a 650-year brood be like, he wondered.
When the first buboes started forming in his armpits and groin, he had a fairly good idea.