Limoniidae, previously a subfamily of Tipulidae (Limoniinae), are now considered their own family. Both Limoniidae and Tipulidae are part of the larger group of crane flies, Tipulomorpha. Often these are relatively large, grey or white, soft-bodied, legless larvae. The head is inconspicuous, mostly retracted into the thorax and almost completely hidden from view. They are often sold in bait shops, or used as models for tied flies, especially for bass fishing. Usually, larvae are found burrowing in soft sediment of streams, often near algae or woody debris; but some larvae are terrestrial. They vary in feeding strategy, some are predators while others are shredding detritivores and herbivores. Most species have only 1 generation per year. Pupa usually are found in marginal habitats. Adults resemble giant mosquitoes, with long, delicate legs; however, they do not bite.
Wings and wing pads absent. Eye spots sometimes visible, but compound eyes absent. Segmented legs absent, but sometimes fleshy prolegs present. Sometimes with distinct head, often without head or with head drawn deeply into thorax. Body flattened, cylindrical, or maggot-like.
Mandibles moving against one another along an horizontal or oblique plane. Hardened head capsule always deeply retracted inside thorax; often with length-wise incisions of varying depths beginning at posterior margin of head, and extending forward; in extreme cases head consisting of only several slender rods (visible only via disection of thorax). Spiracles absent (apneustic) or with 1 pair at posterior end of body (metapneustic); posterior spiracles rimmed by 2–7 (usually 5) lobes often fringed with hair. Mature larvae usually 10–25 mm long.
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