The longest insect, a stick insect (Phryganistria chinensis) measures 64 centimetres (25 in) in total length.

https://artsandculture.google.com/story/the-discovery-of-the-world-s-longest-insect-crawling-tree-branches-insect-museum-of-west-china/LwUh5A_WKoT6Jg