Kissing bugs, as their name may suggests, bite mostly at night and around the lips, Dr. Walker says. Also known as “assassin bugs,” they can be found in Southwestern U.S. The bites usually don’t hurt, but they can be itchy, swell and look like hives. The bugs carry a disease-causing parasite in their feces called Trypanosoma cruzi. It causes Chagas disease, Dr. Walker adds. When infectious bug fecal material contaminates the mucous membranes or the site of bug bite on a person, transmission of the parasite can occur, according to Texas A&M University.