.STRUCTURE IS ACTUALLY Curing Americans to all sort of spectacles. On April 8th thousands watched a complete photovoltaic eclipse. Several will certainly be less mesmerized when, in the coming days, trillions of cicadas show up in the nation's Midwest as well as south-east. The swarm is going to be unusually huge due to the fact that pair of sorts of the bug-- Brood XIII and also Family XIX-- are actually arising at the same time. The final time they seemed concurrently was in 1803, when Thomas Jefferson was head of state. Why perform the cicadas possess such an unusual life cycle?