My pet hate in New Zealand was sandflies. They don't fly so you only get bitten below the knees, but you always get LOTS of bites and they treat repellents as ketchup. They also sedate you - there have been occasional cases of people lying down on beaches and getting bitten into coma and death. The only other place I've met them was the northern Adriatic islands (specifically, at the Cres ferry terminal for Istria).