Culicoides ornatus Taylor is known to be a significant biting pest around the north coast of Australia (Reye and Lee 1962, Reye 1991, Wbelan 1991a). Darwin, the principal city in the Northern Territory, has existing and proposed urban areas adjacent to various extensive areas of mangroves in Darwin Harbour which are regarded as probable sources of biting midge pest problems. This paper outlines the results of the biting midge investigations in the Darwin South area with specific reference to C. ornatus. It discusses the implications of the results on the behaviour and possible breeding sites of C. ornatus and suggests a methodology for biting midge surveillance as an aid to urban planning.