294 THE STUDY OF INSECTS 



the air for long periods. This is especially true of some of the smaller 

 species, which often collect in swarms at twilight, forming a small cloud, 



Fig. 503. — Tho- 

 rax of a crane-fly 

 showing the V- 

 Fig. 502. — A crane-fly. shaped suture. 



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. This has suggested the rhyme : — 



"My six long legs, all here and there, 

 Oppress my bosom with despair." 



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

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

 aquatic; 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 larvae of most species are scavengers feeding on decaying vege- 

 table matter, but some feed on living vegetable tissue, and still others are 

 carnivorous. 



The Tipulidae is a large family; nearly 3,000 species are known and 

 about 500 species have been described from North America alone. 



The larvae 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 larvae 

 are about one inch long and of a dirty-grayish color. As the body-wall 

 is of a tough leathery texture these larvae are commonly known as 

 leatherjackets. Serious outbreaks of these pests have occurred at various 

 times in Ohio, Indiana, Illinois, and California. In the case of the 

 species infesting ranges, pastures, and grain and alfalfa fields in Cali- 

 fornia it was found that the larvae usually come out upon the surface of 

 the ground during the night and could be destroyed by the use of poi- 

 soned-bran bait, made by mixing one pound of Paris green, twenty-five 

 pounds of bran, and sufficient water to make a flaky mash. The bait is 

 applied with a broadcast grain seeder. 



There are three other families of closely related crane-flies, namely: 

 the primitive crane-flies, Tanyderidce, which are of interest because they 

 are the most generalized of living crane-flies; the phantom crane-flies, 

 Ptychopterida, of which one species, Bittacomorpka cldvipes, is the most 



