56 



the protection of corn; but it may best be used in combination 

 with some obstruction to the passage of the chinch bug from 

 small grain and grass to corn, — either ditches and furrows, as de- 

 scribed above, or belts of coal-tar along the border of the field. 

 A mixture of coal-tar with oil or grease, ten parts to one, will 

 last without hardening in the sun, from five to ten times as long 

 as the pure tar, but is too fluid to be poured directly on the 

 ground. 



Tobacco water was found frequently fatal to chinch bugs of all 

 ages, but was apparently less effective than the kerosene emulsion. 

 An emulsion of coal-tar likewise gave promise of usefulness, having 

 the advantage in cost over the kerosene mixture, but being some- 

 what less convenient of application. 



On the other hand, infusion of lobelia, coal-tar water, tur- 

 pentine emulsion, lime-water, fresh gas-lime, arsenic, London 

 purple, Paris green, the "Egyptian insecticide," buhach, corrosive- 

 sublimate, and steam, were applied to chinch bugs with discourag- 

 ing results. 



Some starvation experiments not began until September 4, were 

 unsatisfactory because of the lateness of the period, and because 

 most o£ the bugs from the district where the specimens used in, 

 our experiments were collected, proved to be already weakened by 

 disease. Adults and young, — some just hatched, — confined on a 

 dry surface and without food, died in from one to six days.. 

 Other young, taken as they hatched, lived from twelve to twenty- 

 four hours. 



Careful studies of the contagious diseases of chinch bugs, re- 

 vealed in August and September, 1888, the presence of three dis- 

 tinct forms of fungous disease, two of them identical with those 

 reported by me in 1882, and the third new. All these were widely 

 distributed through Southern Illinois, with the possible exception 

 of the region bordering the Ohio Eiver. 



Two of these diseases are produced by thread fungi (Entomoph- 

 thora and Botrytis) which make a rapid external growth after 

 the death of the insect, presently imbedding the body in a 

 snow-white mold; and the third is a bacterial disease, charac- 

 terized by a minute bacillus which has its principal seat in the 

 coeca (not the Malpighian tubules) of the alimentary canal. Many 

 and various culture experiments with the latter were completely 

 successful; but infection experiments could not be made for want 

 of specimens originally free from disease. On the other hand, 

 culture experiments with the Entomophthora and Botrytis were 

 tried without success. 



Among various miscellaneous notes, I have reported the failure 

 of an attempt to force the chinch bug to feed on wild buckwheat 

 ( P(flf/(j(rtiu7n (lumctornw); the very early occurrence of the chinch 

 bug in Edwards county, Illinois, (in 18'23, and again in 1828); the 

 j)roKtration of wheat and com as an effect of chinch-bug injury 

 (due to failure of development of tlie latest circle of "brace- 



