INSECTS IXJUIllOUS TO THE GRAINS AND GRASSES. Gl 



variable and entirely dependent upon local weather condi- 

 tions, twenty miles a day may be considered a fair average. 

 The flights are more rapid and more distance is covered in 

 the early part of the season, when, while crossing the dry 

 prairies, a good wind will often enable them to cover 200 

 to 300 miles in a day. As they first commence to alight 

 in their new feeding-grounds their stay is limited to but 

 two or three days, but later in the season it is considerably 

 lengthened, and, after being once visited, in an infested 

 country swarms will be seen to be constantly rising and 

 dropping during the middle of the day. 



Life-history. — Over all the infested area, and while still 

 sweeping it bare of croj)s and vegetation, the females com- 

 mence to lay their eggs, and continue to deposit them from 

 the middle of August until frost. For this purpose '' bare 

 sandy places, especially on high, dry ground, which is 

 tolerably compact and not loose, ^^ are preferred. " Meadows 

 and pastures where the grass is closely grazed are much 

 used, wliile moist or wet ground is generally avoided.^' 



In such places the female deposits her eggs in masses of 

 about thirty. These are placed about an inch below the 

 surface in a pod-like cavity, which is lined, and the eggs 

 covered by a mucous fluid excreted during oviposition. 

 Erom two to five hours are required for this operation, and 

 an average of three of these masses is deposited during a 

 period of from six to eight weeks. 



As the time of ovipositing varies with the latitude, so 

 the hatching of the eggs occurs from the middle or last of 

 March in Texas till the middle of May or first of June in 

 Minnesota and Manitoba. Until after the molt of the 

 first skin, and often till after the second or third molt, 

 the young nymphs are content to feed in the immediate 



