Entomogenous Fungi. 441 



A culture was made in an Ebrlmeyer-flask partially filled with 

 pieces of sterilized potato. The growth quickly spreads over the 

 entire surface. At the end of about four days, the potato was 

 tinged purple in the near vicinity of the colonies. This color is 

 soon obscured by the dense felt of mycelium which covers the sur- 

 face, and which becomes strongly wrinkled as growth advances. No 

 sporophores are produced but the surface is covered by a thick 

 coating of creamy white conidia. 



SpOROTEICHUM GLOBULTFERUM on the CHIliCH-JBuG. 



In the fall of 1893, Chancellor Snow, of Kansas, kindly sent me 

 a box of chincb-bugs covered with a growth of the so-called Sporo- 

 trichuTn glohuUferum which has been used to such an extent 

 against the ravages of these insects, A pure culture was obtained, 

 but unfortunately the cultures were neglected and died before a care- 

 ful study of its growth on potato and other media could be made 

 The growth on the bug is in the form of a dense felt, not exactly 

 such as occurs in the typical form on the carabid beetle, but indis 

 tinguishable from it as far as microscopic appearance goes. Cul- 

 tures in large flasks may prove it to be the same. A number of 

 experiments were made attempting to produce the disease arti- 

 ficially on various insects. About one hundred live aphids, Aphis 

 hrassicae^ were placed in a cage on a kohlrabbi, and thoroughly 

 dusted with conidia. After about a month had passed, no effects 

 were noticeable and the experiment was discontinued. Many 

 specimens of wireworm, Agriotes mancits, were rolled in a 

 Petrie-dish full of conidia and were then placed in moist soil 

 None of them developed the fungus. Out of four carefully con 

 ducted experiments with white grubs, larvse of Lachnosterna, only 

 one succeeded. Many grubs were dusted with conidia from potato 

 cultures, or rolled in Petrie-dishes containing fruiting threads. 

 Some were even touched with the infected bugs themselves. All 

 of the grubs lived and showed no signs of the fungus. One, how 

 ever, of five grubs dusted with conidia obtained from a sterilized 

 grub, on which the fungus had been grown, succumbed, and showed 

 the disease in its characteristic form. From this a pure culture was 

 obtained by jneans of a dilution culture. The experiments were oi- 

 the whole unsuccessful, but as they were carried on with insects net 

 the natural host of the fungus, they prove nothing as to its efiicacy 

 against the chinch-bug. 



