.STRUCTURE IS Attending To Americans to all type of eyeglasses. On April 8th millions witnessed a total photovoltaic eclipse. Numerous are going to be much less mesmerized when, in the coming days, trillions of cicadas show up in the country's Midwest and south-east. The throng is going to be actually uncommonly big since 2 sorts of the insect-- Family XIII and also Brood XIX-- are actually developing simultaneously. The final time they seemed together was in 1803, when Thomas Jefferson was head of state. Why do the cicadas have such an uncommon life cycle?