46 



The first clearly recognizable cases of fungous disease among- 

 these chinch bugs were found by me in a corn field near Shattuc, 

 Clinton county, July 7, 1887, but as the fungus affecting these 

 insects was not an Empusa, but belonged to a genus (Botrytis) 

 but very rarely parasitic, no especial attention was paid to it at 

 the time. The same fungous affection was next noticed August 

 7, 1888, at Flora, Illinois. September 13, the Empusa of 1882 was 

 collected in Marion county; and September 14, the bacterial form 

 discovered in 1882 was observed in immense numbers in the in- 

 testines of chinch bugs obtained at Odin. 



With this inspiriug evidence that at least three kinds of disease 

 were at work on the chinch bugs of Southern Illinois, active 

 measures were taken at once for the fullest possible study of them 

 from every point of view, entomological, bacterial, and economic. 



Without attempting at this time a full account of our work 

 (still in progress), I give a few items bearing especially on the 

 distribution and activity of these diseases in the State. 



The field at Odin where the bacterial disease was first detected, 

 contained only a very moderate number of chinch bugs for the 

 time and circumstances, and these very unequally distributed. 

 The number of adults, especially, was relatively very small. 

 The bugs had also a feeble vitality, as shown by the rapid- 

 ity with which they died in transit, although put up with special 

 care. Many pupae were very sluggish, moving slowly along as if 

 stiff and feeble, the abdomens noticeably distended and unusually 

 greenish beneath. 



Crushing both dead and living examples, and slightly diluting 

 the fluids with distilled water, immense numbers of bacteria were 

 apparent, moving without flagellar action, unmistakably the same 

 as those studied in 1882. 



Collected in a film on a cover glass, dried, flamed, stained with 

 aniline and mounted in balsam, these bacteria had the appearance 

 of a short-jointed bacillus, with a pale center which did not take 

 the stain. If the fluids were not much pressed or agitated, there 

 were usually visible many globular masses of these bacilli, look- 

 ing like free nuclei, but readily broken up by repeated pressure, 

 the separate individuals swarming everywhere. Sometimes careful 

 crushing in water would enable one to trace the streams of escap- 

 ing bacteria to a portion of the alimentary canal protruding 

 through a break in the crust. 



On the 18th of September, I killed carefully and at once dis- 

 sected a pupa from Odin, presenting the symptoms of disease. 

 First crushing on the slide portions of the fatty bodies, I recog- 

 nized a small number of the usual bacilli, but when I isolated 

 portions of the gastric coeca*, transferred to a clean slide, and 



•The chinch biiK has, bcHldeH the slender MnlplRhlnn tubules, Ave lurpe coGca arising some dls 

 lance anterior to these, which remind one of the so-called heputlc coeca of the cockroach. 



