The largest insects that ever lived were dragonflies with wingspans of more than two feet, grown in an ancient atmosphere so much richer in oxygen that nothing that size could survive in the air we breathe today - Space Daily

The largest insect known to science was a predator called Meganeuropsis permiana, with a wingspan of about 71 centimetres, a little over two feet. It flew in the Early Permian, roughly 285 million years ago, and despite the way it is usually described, it was…