They actually busted this myth on Mythbusters. Adam put his arm into a tube full of daddy long legs. One of them bit him, and nothing really happened. They also analyzed the venom and found that it's not fatal. http://en.wikipedia.org/wiki/MythBusters_(season_1)#Episode_13_.E2.80.94_.22Buried_in_Concrete.2C_Daddy_Long-legs.2C_Jet_Taxi.22