In the Uruana huts we found that vegetable substance called yesca de hormigas (ant tinder) already seen at the cataracts, used to stop bleeding. This tinder, which should be called 'ant's nest', is much needed in a region where there is so much violence. A new species of ant (Formica spinicollis), of a pretty emerald green, gathers this soft cotton-like down from the leaves of a melastomacea to make its nest.