Based on the Wikipedia entry it seems the terms covers a wide range which includes biting and non-biting insects
Examples of families that include species of midges include:[1]
Blephariceridae, net-winged midges
Cecidomyiidae, gall midges
Ceratopogonidae, biting midges (also known as no-see-ums or punkies in North America)
Chaoboridae, phantom midges
Chironomidae, non-biting midges (also known as muffleheads in the Great Lakes region of North America)
Deuterophlebiidae, mountain midges
Dixidae, meniscus midges
Scatopsidae, dung midges
Thaumaleidae, solitary midges
http://en.wikipedia.org/wiki/Midge