49 



under conditions as favorable as possible to their maintenance>- 

 The rapid post-mortem development of the fungus here was quite 

 inexplicable on any other theory than that of its pathogenic 

 character. One specimen, for example, alive in the afternoon, but 

 dead upon the bell glass at noon of the following day, was already 

 completely whitened by a profuse external growth of this Botrytis, 

 already fruiting abundantly. 



Another example, but just dead, (taken from a lot of chinch 

 bugs among which this Botrytis affection prevailed,) upon whose 

 surface no external growth had yet appeared, was seen to be filled 

 and penetrated everywhere with a rudimentary and rapidly grow- 

 ing mycelium certainly not entomophthorous, but agreeing in 

 character with the Botrytis as this appears within the insect. 



As to the distribution of this fungus outside the State, I have 

 no knowledge beyond the fact that it appeared in a small collec- 

 tion of chinch bugs received from Mr. Otto Lugger, of Minne- 

 sota, October 25, 1888, within a fortnight of their arrival here, — a 

 fact which may be explained either as due to its occurrence in 

 Minnesota, or as a result of accidental infection at the office after 

 the bugs arrived. 



An observation of especial interest was made November 1 by 

 Mr. Marten, at Champaign, a large beetle {Parandra hrunnea) 

 found dead under a log, being thickly covered with a profuse 

 growth of this same Botrytis. 

 j Descriptions and figures of these fungi, and fuller accounts of 

 the diseases associated with them, may be best postponed until 

 our studies now in progress are further advanced. 



At present it appears that all except perhaps the bacterial dis- 

 ease are closely dependent for their activity on the weather, al- 

 though their generally rapid development over so large a territory in- 

 dicates their presence at all times to a greater or less extent. That 

 the bacterial disease is less dependent upon wet weather for its ac- 

 tivity was shown by occurrences detailed in my entomological re- 

 port for 1882, borne out as these are by our office experiments- 

 this year. While in order to obtain the free and rapid develop- 

 ment of the Entomophthora or Botrytis, it was necessary to en- 

 close the chinch bugs under glass over moist earth, the bacterial 

 disease appeared or continued equally well in specimens kept per- 

 fectly dry, and even where they were evidently perishing from 

 simple drouth. However, the appearance of even this disease only 

 after a season of considerable rain, and our failure to detect it in 

 the field in extremely dry weather, make it probable that this also 

 remains in abeyance under conditions recognized as especially 

 favorable to chinch-bug increase. 



That it is chiefly to the joint action of these various disease- 

 producing fungi, favored as they are by moist weather, that we 

 owe the disappearance of chinch-bug outbreaks, is rendered almost 

 certain by the facts now on record. 



S. E.— 4a 



