THE ORTHOPTERA OF MINNESOTA. 37 



PARASITES AND OTHER ENEMIES OF LOCUSTS. 



Locusts have a large number of parasitic eiiemies,and when- 

 ever locusts, as hosts, become at all numerous, their para- 

 sites become equally and more numerous, and soon gain 

 master}'. This struggle for existence is constantly going 

 on ; it is a very cruel one, as no pardon is asked nor 

 given. This is of course a good thing for the farmer, as 

 without it all the labor he performs to rid his fields of such 

 intruders would be performed in vain. When locusts be- 

 come very numerous it seems as if they became weaker and 

 predisposed to catch any disease that is liable to attack 

 them, and they soon succumb. Especially a bacterial dis- 

 ease is ver}' effective, and carries off many, even nearly all 

 locusts in a given region. But this takes place only when 

 the climatic conditions have been such as to have weakened 

 the vitality of these insects. Continuous rain is very injuri" 

 ous to such sun- and warmth-loving beings. During rain 

 locusts hide and take no food, hence a long continued spell 

 of rain does not alone injure their constitution, but also 

 forces them to a long abstinence from food, a condition very 

 bad for such hungry and greedy beings. 



Besides such bacterial diseases others caused by higher 

 organized plants, such as fungi, frequently occur and more 

 than decimate the hosts of hungry locusts. 



We can always be certain that in dry seasons locusts 

 will become destructive, even very much so, simply because 

 they are healthier, hence devour more, and as plants do not 

 thrive as well in a drought}^ season we can soon see how 

 destructive such insects can become if favored by such con- 

 ditions as much sunshine and little rain. They show by 

 their very actions their abhorrence to moisture and damp- 

 ness, and towards evening all, large and small, try to escape 

 the same by crawling upon something that is elevated or 

 higher than the ground. During the night, when all our 

 locusts are more or less quiet and sleeping, and do not pro- 

 duce such loud sounds as the grasshoppers and crickets, 



