They are particularly troublesome in spring and form swarms round one's head, getting in and biting wherever possible. The main species responsible is Leptoconops kerteszi which in the Western Cape is particularly troublesome on the West Coast. Egg development period is 10-12 days. Larvae feed on organic matter near the surface of the moist sand over a long period of 8-10 months. They pupate near the soil surface.
Adults emerge from the pupae, mainly in spring, and mate.
Females disperse 1-2 km in search of a blood meal. Controlling these midges is difficult. Nothing seems very effective in preventing them from biting you. Drainage of breeding areas or using chemical control methods in the breeding areas can be helpful provided these are fairly localised which is not normally the case. These are large biting flies that can be troublesome outdoors.