Mangrove biting midge. Coloured scanning electron micrograph (SEM) of a female mangrove biting midge, (culicoides ornatus) showing the blood sucking stylets (pink) which are inserted into small capillaries in the skin. Biting midge females feed on warm-blooded vertebrates and may be a nuisance to humans who are often in the field. They readily bite humans causing irritating, painful, and, in some cases, long-lasting, lesions. Biting midges do not transmit diseases to humans but scratching of the bites may lead to secondary bacterial infection. Culicoides ornatus are most active in the 2 hour period before and after sunrise and sunset. However, bites can also occur at other times and during the day in or adjacent to their breeding sites. Magnification X 250 when printed at 10cm wide.