184 THE CANADIAN ENTOMOLOGIST. 



to such an extent as to render it permanently unfit for the growth of other 

 crops. Several years ago Prof. W. K. Kedzie, of the Michigan Agricul- 

 tural College, when experimenting in this direction, demonstrated that 

 water charged with carbonic acid or ammonia dissolved a certain portion 

 of the Paris green, but that this was quickly converted into an insoluble 

 and harmless compound by combination with the iron which exists in 

 almost every soil. As rain water always contains more or less of these 

 ingredients, it is more than probable that the small portion of this poison 

 used on potato fields soon loses its poisonous properties in this manner. 

 In any case, one pound of the green spread uniformly over an acre of soil 

 would only amount to less than one-sixth of a grain to the square foot, so 

 that were the poison to remain unchanged, this minute portion might be 

 added to the soil annually for a. century without producing any perceptible 

 deleterious effects on plant growth. It is to be regretted that any one 

 should attempt to excite needless alarm in this way. Caution should be 

 urged in handling this powerful poison, and it is often the case that more 

 is used than is needed ; these points are important and cannot be too often 

 referred to. Paris green is best and most economically used with water in 

 the proportion of one teaspoonful of the powder to a pailful of water, kept 

 well agitated and sprinkled on the potato plants by means of a hand 

 whisk dipped from time to time into the liquid. If the Paris green is 

 pure this proportion is ample, but too often this useful compound is largely 

 adulterated, a practice which some dealers are tempted to adopt from the 

 eagerness with which a large portion of the public run after cheap goods. 

 Paris green is frequently adulterated to the extent of from twenty-five to 

 fifty per cent., chiefly with sulphate of baryta, a cheap and harmless 

 mineral compound. By resorting to practices of this sort dishonest dealers 

 can supply their customers at a less price than the cost of the pure article, 

 and at the same time make large profits. It is a matter of regret that with 

 an Adulteration Act in force, which if properly carried out would at once 

 put an end to these and all such impositions, the public are not better 

 protected. 



The insect enemies of the Potato Beetle are in some localities rapidly 

 increasing in numbers. In the annual report of our Society for the year 

 1871, our esteemed coadjutor, Mr. E. B. Reed, contributed an excellent 

 article on the Potato Beetle, in which he enumerates a number of insects 

 which prey upon this pest in the various stages of its growth, and among 

 them refers to a species of Lebia, one of the active members of that family 



