50 PAPEES OX CEREAL AXD EORAGE IXSECTS. 



most rapid development of the fungus appeared in cages where the 

 bugs had little or no food. In the stock cages only a very small 

 supply of the fungus could be secured until the food was removed, 

 when it soon appeared abundantly upon their dead bodies lying on 

 the soil. 



Conclusions. — From these experiments it is apparent that Sporo- 

 trichum globuYxjerum will to a certain extent develop entirely upon the 

 dead bodies of adult chinch bugs. However, the fungus was easily 

 secured hi the cages containing living bugs artificially inoculated, 

 particularly when the bugs in these cages were given insufficient food 



supply. ..'.'■ 



The indications were also that this fungus is communicable to 

 living chinch bugs, but is evidentlv not verv effective in causing their 

 death unless the bugs possess weakened vitality. This being the 

 case, it would be most effective in nature against old spent adults 

 which have laid then eggs and are comparatively harmless, and it is 

 upon these bugs that the fungus always appeared hi greatest abun- 

 dance, as borne out by field observations during the past three years. 



For this reason, as well as its dependence upon favorable weather 

 conditions, its practical efficiency is very questionable: and since it is 

 unable under favorable conditions of moisture and temperature to 

 rapidly exterminate healthy bugs confined in a cage in the laboratory, 

 little dependence can be put upon it to be used against the insects in 

 the field when favorable moisture conditions are so apt to be lacking. 



SUMMARY. 



Injuries due to the chinch bug west of the Mississippi River are 

 chiefly confined to the States east of the Rocky Mountains where 

 wheat and corn are extensively grown, the most serious outbreaks 

 during 1909 and 1910 occurring in southern Kansas and northern 

 Oklahoma. 



There are two generations each year, one during the spring, which 

 attacks the wheat and corn, and one during the summer, which develops 

 on the corn and hibernates. These last pass the whiter as adults, and 

 in the States west of the Mississippi River prefer for hibernation the 

 dense clumps of red sedge grass in which they collect in the faU. 

 Very few survive the whiter in fallen ears or stalks of corn during 

 severe cold winters, but may survive a mild whiter. Thev flv from 

 the sedge grass to fields of wheat during the first warm days of spring, 

 where the eggs are deposited, and the young hatching therefrom feed 

 with the adults upon the wheat until it has ripened, when they all 

 march in a body to the nearest cornfield. The young become mature 

 on the corn and lay eggs from which hatch the bugs that whiter over 

 as above stated. Weather conditions have much to do with the 



