Even the hardiest of adventurers can be brought to their knees (and the edges of their fingernails) by the nearly invisible but undeniably hostile nono. These small insects are fiercer than lions. Cover yourself in lightweight trousers and long-sleeved shirts and whip out the jungle juice. This little gnat’s bites can leave welts that itch like no other. Fortunately, they are found almost uniquely on beaches and in some valleys, and are not disease carriers.