THE ENTOMOLOGIST. 107 



larva and beetle state, wilhoiit injuring tlie plant. The 

 results of onr experiments and investigations confirm tliis 

 opinion, and this remedy is, no doubt, a reliable one, provided 

 the Paris-green be of good quality. Our experience has also 

 satisfied us that flour is a mucli better substance to mix the 

 green with than either ashes or lime, as the insects eat it 

 more readily, and, at the same time, it adheres more tena- 

 ciously to the surface of the plant, and hence is not so easily 

 washed off by rain. We found good effects from a mixture 

 of one part by weight of Paris-green, with ten or twelve parts 

 of flour, dusted lightly on the vines early in the morning, 

 when the dew is on the foliage. 



" Qtia/tiiiies Required, and Probable Cost j^er Acre. — After 

 a careful estimate, we consider that three pounds of the 

 Paris-green, economically used, will be found sufficient for 

 one acre of potatoes. Assuming fifty cents to be the ordinary 

 retail price per pound of Paris-green, every application of the 

 mixture would cost from two to three dollars per acre, exclu- 

 sive of the labour. If the insect is very abundant, two or 

 more applications may be required, as exposure to wind and 

 rain will eventually remove the powder entirely from the 

 leaves, rendering them liable to further attacks. Some dis- 

 cretion should be exercised in selecting a suitable time for 

 using the mixture, which should not be applied during high 

 winds, or immediately before a rain storm. 



^^ Other Remedies Tried. — We did not content ourselves 

 with the use of Paris-green only, but experimented with as 

 many other substances as the limited time at our disposal 

 would admit of; and, although we would not have the results 

 here given to be considered as final in reference to the mate- 

 rials used, we trust they will be of value as indicating the 

 most promising remedies for further trial. 



"Arse)iiotis Acid {Arsenic). — This chemical being much 

 cheaper than Paris-green, and more uniform in its composi- 

 tion, we hoped it would have proved a practical and sound 

 remedy. We tried it in the proportions of half-ounce, one 

 ounce, and two ounces, to a pound of flour; and while we 

 are not pre]iared, from the few trials we have made, to 

 entirely disapprove of its use, the results we have obtained 

 point to the conclusion that where it has been used in suffi- 

 ciently large proportions to destroy the insect, it has caused 



