The most impressive thing about tropical forests to me are ants, how diverse they are and how many there are. None are more impressive than Paraponera, the Bolas or bullet ant, which is an impressive 24-28 mm long. Although not particularly fast or aggressive, these ants have one of the most painful insect stings known. Forsyth and Miyata refer to the Bolas ant sting as "one of the most painful nonlethal experiences a person can endure". This is a common species; nests of Paraponera are found at the bases of trees on the average of one every 10 m at La Selva. Two of our students have had first hand encounters with these ants; they report that the experience is better imagined than experienced. Don't sit on logs, lean on trunks, or hold on to saplings for support; the ants think these things belong to them. Who wants to argue?