The largest-ever insects known to man are now-extinct species of prehistoric dragonflies, but there are a few different contenders for the largest currently living insect. Stick bugs, such as Southeast Asia's giant walking stick, which can grow to be about 2 feet long, may be among the longest.
There are other measures of insect largeness; while the giant walking stick is long, it is rather thin. The giant weta, an island-dwelling bug that looks like a massive grasshopper, is one of the heaviest insect species, sometimes weighing close to 3 ounces. The Goliath beetle is even more bulky, tipping the scales at 3.5 ounces when they are still just larvae.