LOCUSTS AND GRASSHOPPERS {ACRTDITDM). 131 



maggots have left. So efficient is this parasite in 

 America, frequently the ground is covered with locusts 

 dead and dying from this cause ; and in this manner whole 

 swarms are rendered harmless. It will be remembered 

 that the constant annoyances of these Hies were suggested 

 as at times one of the immediate causes of locust migra- 

 tion. In warm weather, the flies multiply rapidly, pass- 

 incr throuofh their transformations in the course of a 



r-HD 



h 



P"iG. 23. — Methoiic (iJiJerssoni, specially remarkable for its comiilex organs for 

 producing sound. 



fortnight ; but in the cooler seasons the development 

 under ground is delayed, the winter being usually passed 

 in the puparium. 



Kunckel d'Herculais finds that Staurojiotiis niaroc- 

 caniis and other Aridiidse are followed on their devasta- 

 ting march by viviparous Diptera, which deposit their 

 larvce in the bodies of the locusts, the parasitism of 

 these larvse resulting in a sort of rachitic condition, 

 answering to that produced by the Tachina-flies on the 

 Rocky Mountain Locust. It is an odd and interesting 



