An Orillian lung maggot was an undesirable creature. In 2373, facing imminent death in a plasma explosion, Neelix told Tosin that he would have no problem dying if it would get rid of an Orillian lung maggot like him. (VOY: "Fair Trade") Presumably this is a larva (a juvenile form that metamorphoses into an adult) of a creature hailing from or discovered by "Orill".