44 



that locust depredations appeared to lessen materially as the train pro- 

 gressed Avestward after entering- W^yoming. Still even here more of 

 these insects were to be seen among the weeds along the railroad track 

 than was the case during their normal alnindance in pastj^ears. There 

 were a number of kinds to he met with in the grasses about Guernsey, 

 but the prevailing species seemed to be M. 2Mcl'ai'd(!^ M. occidentaJls^ 

 M. atlavis, Aulocara elliott'i^ A. feirioratus^ and still others, which, like 

 M. differentially and M. atlanis^ seem to hatch among rank-growing 

 weeds as well as upon cultivated or distur])ed grounds. 



In trying to find a reason for the greater increase of locusts in cer- 

 tain localities during different years, the matter of rainfall seems to 

 offer an explanation for at least a portion of this variation. It is quite 

 noticeable that when rains fall early in the season the eggs of these 

 insects hatch much earlier than they do when the rains come later, 

 although the temperature may be normal or even above normal. Then, 

 too, after each shower during late spring and throughout the summer, 

 it is seen that additional young ones hatch. During some years it may 

 even be possible for many of the eggs that were deposited the previous 

 fall to remain unhatched for lack of the requisite amount of moisture. 

 Should the following year prjve to be a wet one these eggs might then 

 hatch along with those deposited a 3' ear later. That the present year 

 has been an exceptionally wet one in portions of the Northwest may, 

 therefore, account for the immense numbers of grasshoppers that were 

 to be found in that section. Still, there are limited localities even in 

 this region where scarcely any of these insects were to ])e met with 

 during the present summer, while immediately adjoining they were 

 literall}^ swarming. While returning eastward from Guernsey a severe 

 rainstorm accompanied by hail was passed through. Fully an inch and 

 a half or two inches of rather large hailstones fell over a strip of country 

 several miles in width and many miles in length. During the progress 

 of this storm the thought occurred to me that possibly here was an 

 explanation of the comparative freedom of certain areas right in the 

 midst of others that were greatly overrun l)y destructive locusts. The 

 hail in this instance certainly fell with force and in quantity sufficient to 

 crush out the life of the majority of locusts inhabiting the region in ques- 

 tion. Then, too, these sections of comparative freedom from the pest 

 so frequently observed by the writer are such as are subject to severe 

 hailstorms. 



As intimated on a previous page, the Russian thistle, in addition to 

 affording an al)undant food supply for certain species of the native 

 locusts, provides excellent shelter for their eggs as well as the insects 

 themselves. Tucked away l)eneath these formidable plants both the 

 insects and their eggs are well protected from most of their natural 

 enemies, as well as from sudden changes of weather. This being true, 

 the Russian thistle no doubt must have had something to do with pro- 



