'Thorny Stick Insect' usually refers to members of the Heteropterygidae family, usually Aretaon asperrimus (Sabah Thorny Stick Insect) or Trachyaretaon bruechneri (Giant Thorny Stick Insect), which is probably my favourite stick. This is what I presume they are calling 'Prickly Stick Insect', but which I'd call a Macleay's Spectre, Extatosoma tiaratum.