BRITISH APHIDES. 



be a connecting mycelium. On cutting into such 

 bodies their contents will be found leather-like and 

 tough, and finally the insects dry into hard masses. 



Dr. Worthington Smith states that the potatoe 

 fungus, Peronospora infestans, passes its mycelium 

 into the bodies of the Aphides, which commonly infest 

 the stalks of that plant when diseased. That Aphides 

 are liable to fungoid growths is clear from the 

 observation of many investigators. 



In 1873 Dr. J. Le Conte, of Philadelphia, remarked 

 on the epidemic diseases of insects ; and with a view to 

 their extermination, he proposed something like the 

 inoculation of disease. Dr. Rees and Mr. A. Giard 

 subsequently discussed the same subject with the like 

 intent. 



Very much to the same purpose Prof. Metschnikow 

 suggested the deliberate cultivation of such fungoid 

 growths as produce diseases in insects ; and he pro- 

 posed that the fungi so cultivated should be scattered 

 in places infested by noxious insects, with a view to 

 their extermination. 



Dr. H. A. Hagen, of Cambridge, Mass., made 

 experiments on the effects of common yeast on 

 beetles, &c, and he states that sprinkling the bodies 

 with this substance resulted in death of the insects 

 within the space of three or four days. He thinks 

 that destruction of the animal organs is caused by the 

 penetration of the mycelium, which produces the 

 consequent disintegration of the parts. 



It is not clear how this yeast-plant is most advan- 

 tageously ;i|>|>lied ; but possibly a few insects, anointed 

 with the scum from the brewing of beer, when set at 

 liberty, would cause the required dissemination. I 

 would commend such experiments to the notice of 

 those who are overrun with the common cockroach. 



A little attention will always keep the " green-fly " 

 out of greenhouses and forcing-pits. The great thing 

 to avoid is insect possession through a neglect of the 

 early broods of the year. These broods, being less 



