31 



but the habit of depositing egg's in cotton branches and the tassel 

 stalks of corn suggest the burning of all egg-infested cotton and corn 

 stalks, which has been the common practice upon some plantations. 



The field locust eggs are common hosts of two hymenopterous 

 parasites, Eupelmus xiphidii Ashm. MS. and Macroteleia sp. near 

 floridana Ashm. In breeding cages the latter appeared during the 

 month of June, while the former appeared at intervals from Jul} 7 21 

 until October 15; the majority, however, emerged between August 25 

 and September 18, and all were females. It is interesting to note that 

 the parasite delays development and reaches the adult stage at a time 

 when locust eggs are fresh and more or less abundant. 



From adult locusts a number of Sarcophagid flies, Helicobia helicis 

 Town, were bred. The maggots appeared on September 15, pupated 

 September 17, and matured September 21. 



THE RELATION OF CREVASSES AND RAINFALL TO THE APPEARANCE AND 

 DISAPPEARANCE OF GRASSHOPPERS. 



Planters operating behind the levees of the Mississippi River have, 

 from experience, begun to expect insect outbreaks of one kind or 

 another after overflows. In many sections the Southern grass or army 

 worm (Laphygma frugiperda) makes its appearance in damaging num- 

 bers, while in other places grasshoppers and the army worm may 

 both become destructive. It has been frequently observed that pre- 

 vious to crevasses predaceous beetles of many kinds are abundant on 

 alluvial lands. They feed upon the army worm and easily keep them 

 in check. During crevasses the beetles are either destroyed or are 

 carried to other places by the flow and rush of the crevasse water. 

 As soon as the water recedes and the land is put in cultivation the 

 army-worm moths from neighboring sections fly in, and as this species 

 is a rapid breeder, the crops of the overflowed area are soon infested 

 with armies of caterpillars. It is usually a month or more before the 

 predaceous beetles can migrate in numbers sufficient to check and 

 overcome the march of the caterpillars. 



In the case of the grasshopper the conditions are somewhat differ- 

 ent. A part of the overflowed land may be thrown out of cultivation 

 a season or more, and thus nesting places are provided. Should heavy 

 rains prevail during May and June of the season immediately follow- 

 ing the crevasse, nothing is heard of the ravages of grasshoppers; but 

 should dry summers follow, the conditions for grasshopper propaga- 

 tion and development are much more favorable, and complaints are 

 usually common. The relation of predaceous beetles to grasshoppers 

 is not so intimate as in the case of the beetles and the army worms, 

 though it must not be wholly disregarded, nor are the rains so destruc- 

 tive to the army worms as to grasshoppers. 



