The crane flies (Tipulidae) are a family of insects that closely resemble giant mosquitoes. Like the mosquito, they are in the order Diptera (flies) and are sometimes called mosquito eaters, mosquito hawks, or skeeter eaters. They are also one of three unrelated arthropods named Daddy long-legs. The other two are the harvestmen and vibrating, cellar or house spider. As such, Crane Flies are wrapped up in the myth of being the most poisonous spider, but unable to bite humans. This is incorrect: they are clearly insects rather than spiders, as they possess only six legs rather than the arachnid eight. Also, Crane flies do not bite humans. They drink only water when young and do not usually feed at all when they are adult, as they only live for a few days to mate.
In appearance they seem long and gangly, with very long legs, and a long slender abdomen. The wings are often held out when at rest, making the large halteres easily visible. Unlike mosquitoes, crane flies are weak and poor fliers, so they can be caught easily and without effort. However, it is very easy to accidentally break off their delicate legs when catching them, even without direct contact. This may help them to evade the birds who pursue them as prey.
Temperate species range up to 60 mm in size, while tropical species have been recorded at over 100 mm. They are attracted towards light. The females have swollen abdomen (because of eggs held inside) in comparison to the males. The female abdomen also ends in a pointed ovipositor that looks a bit like a stinger.
Adult crane flies feed on nectar or not at all, while their larvae, called leatherjackets, consume roots (such as those of turf grass in backyard lawns) and other vegetation, in some cases causing damage to plants. Therefore the crane fly is occasionally considered a mild turf pest in some areas. Some leatherjackets are aquatic.
At least 14,000 species have been described (most of them by the specialist Charles P. Alexander), making Tipulidae the largest family of Diptera. The Giant Crane Fly (Holorusia rubiginosa) of the ‘West’ (Western United States) can reach 38 mm (1-3/8 inches). Some Tipula species are 64 mm (2-1/2 inches). There are many smaller species (known as bobbing gnats) that are mosquito-sized, but they can be distinguished by the V-shaped suture on the thorax and a lack of ocelli.
They are the food source of many birds.