Why don't giant prehistoric insects still exist?

Three hundred million years ago, dragonfly-like creatures with wingspans stretching 70 centimeters patrolled the skies of a ...
Earth.com

Earth's first insects were massive, some having wingspans over two feet long, and scientists aren't sure why

Scientists rethink why giant insects once ruled the skies, finding oxygen may not explain their size or disappearance.

Explanation for why we don’t see two-foot-long dragonflies anymore fails

The problem with diffusion is that it’s notoriously slow. The oxygen constraint hypothesis argued that the larger the insect ...

Giant dragonflies once roamed Earth’s skies. New research upends the textbook theory of why they went extinct

Insects first took to the skies about 350 million years ago, some 200 million years before birds first flapped their wings.
Briefly on MSN

South African scientists debunk ancient myth about why prehistoric insects grew so large

Researchers from the University of Pretoria debunk the myth that high oxygen levels were essential for ancient insects' 70cm ...