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 Major Groups | Insecta (insects) | Diptera (true flies) | Dixidae


Major Group: Insecta

Descriptive Features:

  • head capsule complete, not retractile into thorax
  • mandibles usually with several teeth
  • abdomen 9-segmented
  • paired prolegs only on 1st and 2nd abdominal segments
  • posterior abdomen bearing lateral, frequently setose, lobes on each side of a conical anal process
  • Total length: up to 6mm


    Taxonomic Checklist: Species (both genera were formerly known as Dixa in Australia)
    Dixella humeralis Tonnoir
    Dixella nicholsoni Tonnoir
    Dixella tasmaniensis Tonnoir
    Dixella unipunctata Tonnoir
    Nothodixa flavicollis Tonnoir
    Nothodixa geniculata Tonnoir

    Distribution: Australia wide

    Sensitivity Rating: SIGNAL grade 7

    Functional Feeding Group: filtering collectors


    Mt Wills Creek near Dartmouth, Vic

    Ecology: Instream habitat: Commonly known as ‘meniscus midges’, dixid larvae are usually found in fresh, still or slowly flowing waters such as dams, ponds, lake edges and stream backwaters. They live in the meniscus that forms the interface between the water and leaves of macrophytes, overhanging riparian vegetation, or flotsam accumulations, but also in the water surface film itself. Pupae are usually found above the water level on a rock or piece of emergent vegetation. Adults remain close to larval habitats.
    Feeding ecology: Dixid larvae feed by filtering fine particles and planktonic algae from the surface film and just beneath the water surface, using sweeping movements of the brush-like mouthparts. Adult midges do not feed.
    Habit: Larvae hang in the water surface film curled in a ‘U-shape’ and can swim with a jerky motion. When threatened, they dive under the water to resurface later. Pupae can swim. Adults may rest in shaded places or form swarms close to larval habitats.
    Life history: Females lay eggs in masses at the edge of water bodies. Pupation can occur in water but typically takes place in damp earth or above the water surface on adjacent plants.


    Information Sources: Bugledich 1999, Colless & McAlpine 1991, Hawking & Smith 1997, Williams1980, Evenhius 2007, Gooderham & Tsyrlin 2002, Ferrington et al. 2003
    Key to Genera: none
    Key to Species: none