The highland midge (scientific name: Culicoides impunctatus; Scots: Midgie; Scottish Gaelic: Meanbh-chuileag) is a species of small flying insect, found across the Palearctic (throughout the British Isles, Scandinavia, other regions of Northern Europe, Russia and Northern China) in upland and lowland areas (fens, bogs and marshes). In the north west of Scotland and northern Wales the highland midge is usually very prevalent from late spring to late summer.  Female highland midges are well known for gathering in clouds and biting humans, though the majority of the blood they obtain comes from cattle, sheep and deer. The bite of Culicoides is felt as a sharp prick. It is often followed by irritating lumps that may disappear in a few hours or last for days, depending on the individual.
Following Scotland's exceptionally cold winter in the early part of 2010, scientists found that the prolonged freezing conditions, rather than reducing the following summer's midge population in the Scottish Highlands, in fact increased it as the cold weather had reduced the numbers of its natural predators, such as bats and birds.
Female midges tend to bite close to their breeding site (although they have been found up to 1 km away) and near to the ground. They are most active just before dawn and sunset but bite at any time of day. Midges are less active with wind speeds of over 10 km/h (3 m/s; 6 mph), or humidity below 60–75%.
Dry cloudless conditions are unfavourable to midges, thus they are prevalent in humid, wet and cloudy conditions. Rain does not deter them, nor does darkness. However, they tend not to go into houses or buildings, but will enter tents.