"Caterpillars in Hawaii trap snails with silk webs and devour their captive prey alive, scientists announced today.

Predatory caterpillars are very rare -- only a few other species are known in the world. Of the 150,000 species of moths and butterflies known worldwide, only about 200 are predatory."

http://www.livescience.com/animalworld/050721_caterpillar.html