 Of the 26 species of the genus "Lonomia" found on the American continent, only "Lonomia obliqua" and "Lonomia achelous" have caused severe reactions, leading to hemorrhagic syndrome.Since 1989 the number of human accidents caused by these caterpillars has been increasing in the southern region of Brazil.Most victims were male (63%), many were between 0 and 19 years old (45%), and lesions are especially common on the hands (38%).