All of the 217.72.208 series IP addresses from 11-40, 64-99 & 128 belong to Tiscali bots. The rest of that group are static, but still belong to Tiscali. If you want it to say "bot", that's simple enough. Change the code to say:
If instr(uagent,"IstellaBot") Then strBrowser = "Istellabot"