Alderflies, dobsonflies, fishflies

Code QM999999

See Key to Families of Australian Aquatic Neuroptera & Megaloptera Larvae

The Megaloptera are holometabolous insects, with about 300 species in 2 families worldwide. Adults have unspecialised mandibulate mouthparts, including strong mandibles, unequal wings with large plaited anal field on hind wing that infolds when wings at rest over back and a soft abdomen.

Larva are prognathous, with well-developed mouthparts, including 3 segmented labial palps (similar-looking gyrinid beetle larvae have 1-2 segmented palps); spiraculate with gills consisting of 4- to 5-segmented (Sialidae) or 2-segmented lateral filaments on abdominal segments; abdomen terminating in an unsegmented median caudal filament (Sialidae) or a pair of anal prolegs. Pupa beetle-like, except mobile on free legs and with pupal head similar to that of larva, including functional mandibles.

Larvae (sometimes called hellgrammites) have 10-11 instars and take at least one year, usually two or more, to develop. Pupation is away from water, often in chambers in damp soil under stones, or in damp timber. Larvae are predatory in lotic and lentic waters, and are intolerant of pollution.