[1][2] They are noted for their elongated shape and colorless, transparent bodies.

[3] The species can be found in north-eastern North America (Canada,[4] and United States), Northern Europe, including United Kingdom, Lithuania,[3] Norway, Finland, and the Netherlands from sea level to 1,116 metres (3,661 ft) asl.

[3] The habitat is either lotic or lentic,[7] including man-made water bodies such as gravel pits.

Populations in Europe are genetically relatively homogeneous, perhaps reflecting postglacial colonization representing a single lineage.

There is some evidence of two different major lineages, perhaps representing cryptic species or subspecies, with hybridization that have boosted genetic diversity.