A few solitary midges are found in the Southern Hemisphere, but Thaumaleidae are generally an Holarctic family.

However, unpaired prolegs, a ventrally directed truncate head, and prothoracic spiracles on a short respiratory tube differentiate them.

For further information see * Family keys and image Adult Thaumaleidae are encountered infrequently, usually close to the hygropetric aquatic larval habitat.

Thaumaleid larvae are usually hygropetric in vertical, thin water films alongside waterfalls and torrents.

Had Thaumaleidae not come into prevailing usage, Orphnephilidae would continue in use despite the fact that Orphnephila is a junior synonym.