46 PAPEES OK CEREAL AND EORAGE INSECTS. 



occurring chiefly among the old spent and therefore practically 

 harmless bugs of the hibernating brood, they having already per- 

 formed their mission of depositing their eggs. Since the fungus is 

 so dependent on meteorological conditions, it can not be depended 

 upon to exterminate the chinch bugs in this region. Farmers can 

 accomplish a great deal more by employing methods more under 

 their control. 



OFFICE STUDIES IN WASHINGTON, D. C. 



The following experiments were conducted at Washington, D. C, by 

 the junior author who did the work on a table in an office room with 

 no facilities for more elaborate experimentation. He entered into 

 the investigation with a view of determining if the growth of tins 

 fungus is confined to the dead bodies of the chinch bugs and other 

 insects, as the preceding field observations had, in most cases, borne 

 out this supposition. These experiments led to a further study of the 

 behavior of this fungus among living chinch bugs, and the results are 

 here presented, in the hope that a better and more clear understanding 

 may be had of what was observed to occur in the fields. 



In these experiments the author is greatly indebted to Prof. F. M. 

 Webster, of this bureau, under whose direction the work was done. 

 Also to Dr. Flora W. Patterson, mycologist, Bureau of Plant Industry, 

 for her valuable suggestions and kindness in determining the fungus. 



Sporotrichum globuliferum was secured for these experiments by 

 placing under a bell jar, on blotting paper kept constantly moist, 

 dead bugs taken at Wellington, Kans., from beneath leaf sheaths of 

 cornstalks, where they had died the previous autumn. The fungus 

 was also secured by placing on moist blotting paper dead bugs col- 

 lected in clumps of Andropogon scoparius, where the adults .were 

 hibernating but among which no fungus was observed. From 2 to 4 

 of all the dead bugs so treated became covered with the white fungus 

 (fig. 15). The fungus was obtained also from live bugs collected from 

 these same stools of Andropogon, confining the bugs in small cages of 

 wheat kept well moistened. Some of these bugs died in the cages and 

 on their bodies, lying upon the soil, the fungus appeared and was first 

 observed eight days after the live bugs were placed in the cages. 



During the spring of 1909, in the laboratory at Wellington, Kans., 

 the senior author confined, on potted, growing wheat plants, numbers 

 of living chinch bugs which were collected from tufts of Andropogon 

 scoparius. The fungus appeared on several of the bugs which had 

 died and were in the soil. He also obtained the fungus on adult dead 

 chinch bugs collected from the tops of wheat blades and put on potted 

 wheat plants. In these experiments the soil had been previously 

 sprayed with a weak solution of corrosive sublimate for the purpose 

 of killing any fungus spores that might have been present in the soil 



