A spy in the sky not much bigger than a fly has been developed by a top American university. Scientists at Harvard have invented a robotic fly to send on reconnaissance missions in areas too dangerous for humans, such as those contaminated by chemical or biological weapons. It can also be used to find hidden bombs and in search missions. The "flybot", which can fit on a fingertip, is made of lightweight carbon and weighs less than a pin. Researchers, led by Professor Robert Wood, spent seven years on the project with the backing of the US military. "The...