page_title: Snakefly
section_title: Life cycle
hierarchical_section_title: Snakefly / Life cycle
caption_attribution_description: Larva of snakefly, Raphidia sp. (collected on dead pinetree in Russia, Tver' Province, near village Staroe)
context_page_description: Snakeflies are a group of predatory insects comprising the order Raphidioptera with two extant families: Raphidiidae and Inocelliidae, consisting of roughly 260 species. In the past, the group had a much wider distribution than it does now; snakeflies are found in temperate regions worldwide but are absent from the tropics and the southern hemisphere. They are a relict group and have been considered living fossils, as species from the early Jurassic period closely resemble modern-day species.
  An adult snakefly resembles a lacewing in appearance but has a notably elongated thorax which, together with the mobile head, gives the group their common name. The body is long and slender and the two pairs of long, membranous wings are prominently veined. Females have a large and sturdy ovipositor which is used to deposit eggs in some concealed location. They are holometabolous insects with a four-stage life cycle consisting of eggs, larvae, pupae and adults. In most species, the larvae develop under the bark of trees. They may take several years before they undergo metamorphosis, requiring a period of chilling before pupation takes place.
context_section_description: Snakeflies are holometabolous insects, having a four-stage life cycle with eggs, larvae, pupae and adults. Before mating, the adults engage in an elaborate courtship ritual, including a grooming behaviour  involving legs and antennae. In raphidiids, mating takes place in a "dragging position", while in inocelliids, the male adopts a tandem position under the female; copulation may last for up to three hours in some inoceliid species. The eggs are oviposited into suitable locations and hatch in from a few days to about three weeks. 
  The larvae have large heads with projecting mandibles. The head and the first segment of the thorax are sclerotised, but the rest of the body is soft and fleshy. They have three pairs of true legs, but no prolegs. However, they do possess an adhesive organ on the abdomen, which they can use to fasten themselves to vertical surfaces.
  There is no set number of instars the larvae will go through, some species can have as many as ten or eleven. The larval stage usually lasts for two to three years, but in some species can extend for six years. The final larval instar, the prepupal stage, creates a cell in which the insect pupates. The pupa is fully capable of movement, and often leaves its cell for another location before the adult emerges. All snakeflies require a period of cool temperatures (probably around 0 °C (32 °F)) to induce pupation. The length of the pupation stage is variable. Most species pupate in the spring or early summer, and take a few days to three weeks before ecdysis. If the larvae begin pupation in the late summer or early fall, they can take up to ten months before the adults emerge. Insects reared at constant temperatures in a laboratory may become "prothetelous", developing the compound eyes and wingpads of pupae, but living for years without completing metamorphosis.
caption: Larva
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