Abstract
Recent ecological surveys have resulted in rearing examples of the five British members of the genus Lipsothrix (Diptera, Limoniidae). These have provided samples for investigating the morphology of their thoracic spiracular gill by the use of scanning electron microscopy. This reveals unique characteristics for the five species available. The differing structures may relate to varying larval habitats. A species identification key for pupae is based on features of the plastron. Information from the juvenile stages supports the placing of Lipsothrix in the Limoniinae.