.NATURE IS TREATING Americans to all type of spectacles. On April 8th thousands witnessed an overall photo voltaic eclipse. Many are going to be actually much less charmed when, in the coming days, trillions of cicadas appear in the nation's Midwest and also south-east. The throng will definitely be actually unusually large considering that pair of kinds of the insect-- Family XIII as well as Brood XIX-- are actually emerging concurrently. The last opportunity they showed up simultaneously resided in 1803, when Thomas Jefferson was actually president. Why carry out the cicadas possess such an unusual life cycle?