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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

A case of mistaken identity: Crane flies, Family Tipulidae


Crane flies often rest in grass or on vegetation.


A couple of weeks ago, my friends at WTOP inquired about exceptionally large mosquitoes making an unnerving appearance in the Washington, DC area this spring. This case of mistaken identity is not at all unusual, for these large flies really look like colossal mosquitoes. As a child growing up in rural New Jersey, I was often regaled by an old timer named Farmer George. One remarkable tale he told was of the “Jersey skeeters”, mosquitoes so large a couple of them could “grab you by the ears and carry you away.” For the past week or two I have enjoyed “Jersey skeeters” around my porch lamp in the evenings. Although they belong to the clan of mosquito-like insects, these large and fragile flies are rightfully known as crane flies.

A mosquito this big could really do some damage!

With long legs and delicate wings, crane flies certainly have the appearance of mosquitoes on steroids. (To view real mosquitoes like as the ferocious Asian tiger, click here). Little is known about the feeding habits of the adults, but they surely do not bite humans or carry away youngsters. Their mouthparts are elongated and probably adapted to feeding on liquid food such as the nectar of flowers. Feeding is not the most important item on the to-do list of the adult crane fly, but finding a mate is. Male crane flies are the first to emerge from their pupal cases and their first task is to search for females. After finding the fly of their dreams, the couple mates and the female deposits eggs in the appropriate habitat, which could be water, soil, or a rotten log, depending on the species.

Crane fly larvae, called leather jackets, are found in rotting wood. 

The eggs hatch into maggots that are sometimes called leatherjackets. Crane fly larvae eat a variety of things. Many species live in moist soil or rotting wood and eat decomposing plants and other microscopic organisms associated with organic matter. Some crane fly larvae live in water and have gills. They are predators of other small invertebrates or may feed on algae and moss. Most craneflies are important recyclers of organic material, but a few attack living plants and can be pests. Recently, a crane fly native to Europe was introduced to New York State where it has become an important pest of grass in lawns, parks, and golf courses. The larvae eat roots and may kill large patches of turf.

In addition to their important role as recyclers, crane flies are a fine source of food for many nesting birds at this time of year. So, on these warm spring evenings when you see those large crane flies around your porch lamp, you may want to dispel the fears of the youngsters and tell them all the good things crane flies do. Or I guess you could tell them about Jersey skeeters.


Sipping aphid honeydew from a leaf is a good way to carbo-load if you are a crane fly.


I thank my friends at WTOP for providing the inspiration for this episode. To learn more about crane flies, please visit the following web sites: