504 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



Grasshoppers. There are many species of grasshoppers that 

 occur in fields or meadows in greater or less numbers every 

 year. The Rocky Mountain locust, that lives permanently on 

 the high plains of some of the Rocky Mountain states, was for 

 many years the best known of these because of its great 

 migrations into the Mississippi Valley where it destroyed all 

 the vegetation to be found there. The last of these migrations 

 was in 1877. The settling and consequent changed conditions 

 of the regions in which this grasshopper breeds have put a 

 stop to the great flights. 



Grasshoppers lay their eggs in masses in the ground, and cover 

 them over with a sticky fluid that forms a capsule-like covering 

 when dry. Meadows and pastures or bare, dry, rather firm 

 ground, are the places usually selected for egg-laying. The wing- 

 less young, or nymphs, that issue the following spring feed on 

 grasses or any other available vegetation. When the food 

 becomes scarce they may travel in great numbers as do the army 

 worms, devouring every green thing in their path. However, 

 they cannot travel far in this wingless stage, and even after 

 acquiring their wings most kinds seldom fly far from their 

 breeding grounds, and so are easily controlled. If the places 

 where the eggs are deposited are plowed during the fall or early 

 spring most of the eggs will be destroyed or buried so deep that 

 the young cannot come to the surface when they hatch. It is 

 sometimes practicable to burn over a field where the young 

 occur in great numbers and thus destroy them before they 

 migrate to cultivated fields. On hard smooth ground many 

 may be killed by rolling with a heavy roller. When the nymphs 

 are migrating a field may be protected by ditching as for the 

 army worms (page 484). The poisoned mash (page 415) rec- 

 ommended for use against cutworms, may also be used with 

 success against the grasshoppers. Various forms of hopper- 

 dozers have been contrived for catching the wingless grass- 

 hoppers. The most common is a long, shallow pan or tray 

 mounted on runners in which is placed a little water covered 

 with kerosene or crude oil. Oil or coal tar may be used 

 without the water. The back and ends are provided with 

 walls about three feet high to prevent the grasshoppers from 



