INSECTS AFFECTING GRAINS, GRASSES, ETC. 



97 



sidered a fair average. The flights were more rapid and more 

 distance was covered in the early part of the season, when, while 

 crossing the dry prairies, a good wind often enabled them to cover 

 200 to 300 miles in a day. As they first commenced to alight in 

 their new feeding-grounds their stay was limited to but two or 

 three days, but later in the season it was considerably lengthened, 

 and, after a section was once infested, swarms were seen to be 

 constantly rising and dropping during the middle of the day. 



Life History. Over all the infested area, and while still sweep- 

 ing it bare of crops and vegetation, the females commence to lay 

 their eggs, and continue to deposit them from the middle of August 

 until frost. For this purpose " bare sandy places, especially on 



FIG. 74. Rocky Mountain locusts: a, a, a, females in different positions, 

 ovipositing; 6, egg-pod extracted from ground, with end broken open; c, 

 a few eggs lying loose on ground; d, e, showed the earth partially removed, 

 to illustrate an egg-mass already in place and one being placed;/, shows 

 where such an egg-mass has been covered up. (After Riley.) 



high, dry ground, which is tolerably compact and not loose," are 

 preferred. " Meadows and pastures where the grass is closely 

 grazed are much used, while 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 are covered by a 

 mucous fluid excreted during oviposition. From 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. 



