186 BRITISH APHIDES. 



uncorked phial containing about two ounces of carbon 

 disulphide close to the roots of such vines as are 

 infected with Phylloxera vastatrix. The vapour is 

 heavy, and it affects the soil and the insects below. 



The liquid must not be spilled ; and, as the vapour 

 is poisonous, great caution obviously is needed in 

 its use. 



During this last year (1882) M. Monillefert used 

 the sulpho- carbonate of potassium on no less than 

 three hundred and eighty-five vineyards, and he states 

 he has met with great success. The cost varied from 

 0*05 to 0*03 of a franc per stock; which, considering 

 the advantage gained, cannot be considered as an 

 excessive cost to the grower. 



With reference to the hop Aphis, Phorodon humuli, 

 there would seem to be but little doubt as to the 

 hybernation either of the oviparous female or her ego;. 



An application of this sulpho-carbonate to the soil 

 close to the root-stocks early in the spring, when the 

 fundatrix is expected to hatch from the egg, surely is 

 worthy of a trial. Its application to the hop plant 

 cannot have greater difficulties than those experienced 

 in the grape-vine. 



Both in France and America the substance known 

 as Paris-green has been beneficially applied as an 

 insecticide. But as the active principle is arseniate of 

 copper, a highly poisonous preparation, and fatal to all 

 animals, even in small doses, its use cannot be recom- 

 mended. 



Careful washing of the hop plants soo7i after flir 

 appearance of the hop Aphis has often insured a fine 

 cropof blossoms to the grower, and notwithstanding the 

 extra cost it will well repay him for his labour. This 

 may be well understood, when one acre of ground 

 may produce as much as seven hundredweights of 

 hops, representing a value of £22. The loss over the 

 United Kingdom caused by "the fly" during this last 

 year is estimated by a large hop-grower at not less 

 than £1,750,000, of which the labourers, through 



