DIPTERA 



799 



great numbers flying over meadows and pastures. In most cases 

 their power of flight does not seem to be well developed for they fly 

 slowly, and only a short distance at a time. Some species, however, 

 sustain themselves in the air for long periods. This is especially true 

 of some of the smaller species; which often collect in swarms at twi- 



1009. — Wing of Tipula abdominalus. 



light, forming a small cloud, and dancing up and down like some of 

 the midges. Their ability to walk is also poor, for they use their long 

 legs awkwardly, as if they were in the way. Little is known regarding 

 the feeding habits of the adult crane-flies; but some species have 

 been observed to feed on the nectar of flowers. Many species are 

 attracted to lights. 



The larvae of crane-flies vary greatly in habits both as to the 

 situations in which they live and as to the nature of their food. Some 

 are aquatic; Antocha lives in silken cases on rocks in swiftly flowing 

 streams; and members of several other genera live on svibmerged 

 plants. Some live in or beneath damp cushions of moss. Many live 

 in mud or sand along the margins of streams, in swamps, or in shaded 

 woods, while others are strictly terrestrial, burrowing in the soil of 

 meadows and pastures. 



The larvffi of most species are scavengers feeding on decaying 

 vegetable matter, but some feed on living vegetable tissue, and still 

 others are carnivorous. For a detailed account of the life-histories 

 and the structural characteristics of the early stages of the different 

 groups of crane-flies see Alexander ('20). 



The Tipulidas is a large family; nearly 3000 species are known and 

 about 500 species have been described from North Ameiica alone. 

 Among those that are of especial interest are the following : 



The snow-flies, Chionea. — To the genus Chionea belong several 

 species of crane-flies in which the wings are vestigial, being reduced 

 to mere knobs, much smaller than the halteres. These flies are most 

 often seen in winter crawling about on the snow; but they are occa- 

 sionally found in the spring and fall in leaf -mold. 



The meadow-maggots or leather-jackets. — The larvee of some 

 species of crane-flies, most of which belong to the genus Tipula, often 

 do considerable damage in meadows, pastures, and grain fields by 

 devouring the roots of the plants. The full-grown larvas are about 

 25 mm. long and of a dirty-grayish color. As the body-wall is of a 

 tough leatherv^ texture these larvas are commonly known as leather- 



