Cold-water-specialists
Guides
Nymphomyiidae
nymph flies
Nymphomyiidae are a family of minute (approximately 2 mm), delicate flies with highly reduced morphology. They are considered among the most archaic living Diptera, sometimes placed in their own suborder Archidiptera. Larvae are strictly aquatic, inhabiting cold, fast-flowing streams in northern and high-altitude regions. Adults are short-lived, non-feeding, and form aggregative swarms; their wings fracture at the base after mating. The family contains approximately one dozen extant species, currently classified in the single genus Nymphomyia.
Thaumaleidae
solitary midges, trickle midges, madicolous midges
Thaumaleidae is a family of small nematoceran flies in the order Diptera, closely related to Ceratopogonidae, Chironomidae, and Simuliidae. Adults are non-feeding, stocky, yellow to brown flies measuring 3–4 mm, with short antennae no longer than the head. The family comprises approximately 202 extant species in seven genera (Afrothaumalea, Androprosopa, Austrothaumalea, Neothaumalea, Niphta, Thaumalea, Trichothaumalea) plus one fossil genus. Larvae inhabit thin water films on rock surfaces alongside waterfalls and torrents, where they graze on diatoms.