776 Charles Paul Alexander 



ECONOMIC IMPORTANCE 



Economically, crane-flies are found to play a relatively important 

 r61e. The adult flies are entirely harmless, but the larvae of many species 

 are destructive to various crops. In Europe the best-known of such 

 species is Tipula oleracea Linn. In eastern North America the smoky 

 crane-fly, T. cundans Say (called T. infuscaia Loew by Hyslop, lOlO^), 

 working principally on leguminous species, and T. bicornis Forbes working 

 largely on grasses, often become serious pests; in the West the alfalfa 

 crane-fly, T. simplex Doane (Essig, 1913), is often of exceedingly great 

 importance, working on various legumes and grass species. Other species, 

 as T. derbyi Doane and T. aspidoptera Alex., often do considerable local 

 damage. In Japan, T. longicauda Mats, and a species that has been 

 determined as T. parva Loew do very considerable damage to rice and 

 sugar cane. It is to be noted that all these more destructive species 

 belong to the tribe Tipulini, comprising the larger species of crane-flies, 

 and the damage is done by the larvae's feeding on the roots and thus 

 causing the death of the plants. 



The species of Tanyptera Uve in logs or stumps that are fairly sound 

 and free from decay. The larvae of some species of Rhipidia, Limnobia, 

 Trichocera, and other genera, affect stored roots and tubers. The species 

 of Ula and some species of Limnobia live in fungi (Boletus, Armillaria, 

 Hypomyces, and others), and in some cases may be of economic impor- 

 tance in mushroom culture. 



As an element of food for vertebrates, crane-flies occupy a prominent 

 position. The records of Dr. Dallas Hanna and those of the Whitneys, 

 in the possession of the United States Biological Survey, state that 

 larvae representing an unknown species of Tipula are abundant every- 

 where thruout the summer season on St. Paul Island, of the Pribilof 

 group in Bering Sea. These larvae are found around the roots of grasses 

 and herbs, and especially under beds of moss, on the roots of which they 

 feed, killing the moss over considerable areas. Under such a moss bed 

 as many as twenty larvae to the square foot have been collected. The 

 larvae must be of considerable ecological importance because of their 

 food value to birds and foxes. Foxes will dig over large areas of moss 

 beds to feed on them. Thruout the arctic regions the family Tipulidae 



* Dates in parenthesis refer to References cited, page 959. 



