These amazing stick insects are individuals of a species known only by their scientific name of Phobaeticus magnus.  They originate in Laos and north-eastern Thailand and females can reach a length of 3o cm.  The ones pictured below are nowhere near fully grown yet despite already being quite long, the largest being 'only' 15 - 16 cm in length!

When I bought the individuals above they were very tiny, at only about 3 - 4 cm in length, and very cute as you can see here:

Compared to many of the stick insect species that I keep and present at schools / parties etc. this species has a much more 'typical' stick insect shape in that they are very long and slender like a stick or branch.  They use their body shape and colouration to camouflage themselves in their natural habitat, to protect themselves from predators, as they have no other means of defence in that they cannot bite/scratch/run/fly away from danger!!