There are no inscects, millipedes, or centipedes that reach 3'. There are a couple millipedes that get 8-10 inches that are nonvenomous but produce a foul smelling glue if frightened, they are omnivorous scavangers, the borneo stick insect is the longest bug and is harmless, there are a couple attractive centipedes like the redhead and african redlegs that get a bit over 10", they are venomous and while they won't kill you they can kill small mammals or hospitalize a child. they are aggressive obligate predators.
