776 CHARLES PauL ALEXANDER 
ECONOMIC IMPORTANCE 
Economically, crane-flies are found to play a relatively important 
réle. 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 Tzpula oleracea Linn. In eastern North America the smoky 
crane-fly, T. cunctans Say ‘called T. infuscata Loew by Hyslop, 1910), 
working principally on leguminous species, and 7’. 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. derby: Doane and T. aspidoptera Alex., often do considerable local 
damage. In Japan, 7. 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 live 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 
' 2Dates in parenthesis refer to References cited, page 959. 
