Carausius is the Latin name given to stick insects. What does it mean?

Carausius is also the nickname of a Roman Admiral who declared independence for Britain in the 3rd century AD. I would love to find out what the word means. Did it mean 'stick insect' or 'camouflage' or 'stick' - I don't know. How long have stick insects been called Carausius? If there's evidence it goes back to pre-3rd century AD - then that's enough for me. Any brainboxes out there able to help me? I need to know because I'm writing a historical novel. The best answer (the first which realistically answers this question) will get a free copy of my book when it's published!