THE ENTOMOLOGIST. 107 
larva and beetle state, without injuring the plant. The 
results of our experiments and investigations confirm this 
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 much 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. 
“ Quantities Required, and Probable Cost per 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. 
“Arsenious 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 prepared, 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 
