They have Urticating hairs. And the type of urticating hairs the have are said to be the itchiest and worse of all tarantula's. There are like 6 types of differnt U hairs. I think these have type 3 and that type is know to be extremely irritating to mammals. i think I could have explained that better but hopefully you got the gist of it. They have some of the itchiest hairs of all tarantulas - lol
Edit: Urticating hairs or U hairs are little barbed hairs located on certain spots of the tarantula that they use as a defense mechanism..