Entomologist Joachim Bresseel holds a female Phryganistria heusii yentuensis. At 21 inches long (with legs outstretched), it’s the second largest insect species on Earth. (Credit: Bresseel & Constant, Royal Belgian Institute of Natural Sciences) Stick insects have a strange beauty. These slow-moving insects are one of nature's most well-known marvels of camouflage. And their ilk just got a little stranger: entomologists working for the Royal Belgian Institute of Natural Sciences have discovered a brand-new species of stick insect nearly two feet long — the second-longest insect ever discovered.