A crane fly is any member of the dipteran superfamily Tipuloidea, which contains the living families Cylindrotomidae, Limoniidae, Pediciidae and Tipulidae, as well as several extinct families. "Winter crane flies", members of the family Trichoceridae, are sufficiently different from the typical crane flies of Tipuloidea to be excluded from the superfamily Tipuloidea, and are placed as their sister group within Tipulomorpha. Two other families of flies, the phantom crane flies (Ptychopteridae) and primitive crane flies (Tanyderidae), have similar common names due their similar appearance, but they are not closely related to true crane flies.
Adults have a lifespan of 10 to 15 days. The adult female usually contains mature eggs as she emerges from her pupa, and often mates immediately if a male is available. Males also search for females by walking or flying. Copulation takes a few minutes to hours and may be accomplished in flight. The female immediately oviposits, usually in wet soil or mats of algae. Some lay eggs on the surface of a water body or in dry soils, and some reportedly simply drop them in flight. Most crane fly eggs are black in color. They often have a filament, which may help anchor the egg in wet or aquatic environments.
Crane fly larvae (leatherjackets) have been observed in many habitat types on dry land and in water, including marine, brackish, and fresh water. They are cylindrical in shape, but taper toward the front end, and the head capsule is often retracted into the thorax. The abdomen may be smooth, lined with hairs, or studded with projections or welt-like spots. Projections may occur around the spiracles. Larvae may eat algae, microflora, and living or decomposing plant matter, including wood. Some are predatory.
