95 



bugs were numerous on the ground in all infested fields, some showing 

 the white fungus of Sporotrichum, but many with no trace of that 

 or any other fungous growth. At least 95 to 99 percent of the young 

 bugs that had hatched before May 25 were killed by these beating 

 rains. In all the more heavily infested fields the ground around the 

 wheat plants looked as if sprinkled with red pepper because of the 

 abundance of young bugs imbedded there in the mud; and in only 

 one instance did these dead young give any evidence of fungous in- 

 fection. Where streams rose and flooded bottomland wheat in a way 

 to leave the tops of the plants projecting above the flood, the bugs 

 availed themselves of this means of escape from the waters, climbing 

 the stems and remaining until the ground was exposed again, and then 

 returning to the bases of the wheat plants. 



The period of egg-hatching extended from May 20 to June 20. It 

 was difficult to say just when the young were most abundant in the 

 fields, the weather for nearly all May and June being an alternation 

 of short moderately w r arm periods, during which the eggs hatched in 

 fair numbers, and heavy rains which the young were too small and 

 weak to survive. There were thus alternating periods of a moderate 

 abundance and unusual scarcity of the young in all the central and 

 northern parts of the infested area; and by June 20 all danger of 

 serious injury by chinch-bugs in 1915 had passed. Nevertheless there 

 were young enough in a few fields to have warranted their destruction 

 by means of the creosote line and post-hole traps, but when these 

 fields were harvested, about July 1, they contained, owing to the wet- 

 ness of the season, so heavy a growth of wild grasses available as food 

 for the chinch-bugs that there was no movement of the insects out of 

 the stubble. 



Eggs of the second generation were fairly numerous in corn fields 

 by the second week in August, and young were appearing in moder- 

 ate numbers by the middle of that month; but many were killed by 

 the heavy rains which fell over the whole of the infested area August 

 20 and 21. Over eight inches of rain fell at a number of places in 

 the southwestern part of the state during these two days. These heav- 

 iest rains of the season had much less effect than those of May and 

 June, since most of the bugs were at this time in the corn where they 

 were protected from the driving force of the storms. From August 

 20 to about September 7 eggs and young could be found in moderate 

 numbers in scattered fields in all the more heavily infested territory, 

 and most of these young reached maturity and went into winter quar- 

 ters. Examination of the usual hibernating places made during the 

 winter of 1915-16 have convinced us, however, that chinch-bugs are 

 not now present in sufficient numbers to cause any damage in 1916, 

 unless conditions should be unusually favorable to their multiplication. 



While the exceptional spring and summer rains were thus the prin- 

 cipal causes of the arrest of this destructive insect invasion, certain 



