174 
Experiment 10.—Two Scelodonta larv® were treated as above, 
with a saturated solution of carbolic acid, and, forty minutes after¬ 
wards, were taken out and found alive but stupid. They were re¬ 
turned to the earth at once. Three and one-half hours later they 
were still living, and were again returned to the earth. A hole was 
now made as before, and in this a lump of crystallized carbolic acid 
about as large as two peas was dropped; but even this was not 
effective, and seven hours later both were apparently still uninjured. 
Experiment 11.— The experiment just mentioned was repeated with 
twiceVe quantity of the solution of carbolic acid, but with the same 
results as before. Examined two hours after treatment, and again 
in eight, the root-worms were alive and well. 
Experiment 12.—Two larv® were next buried, as usual, and a hole 
was made at the middle of the box, in which a half teaspoonful of 
bits of crystallized carbolic acid was dropped, tne hole being then 
closed with earth. In an hour and a half the larv® were seemingly 
dead, and were returned to the earth after examination. Sixteen 
hours thereafter neither showed any signs of life. 
From the experiments just related, it is clear that carbolic acid 
can be used with effect only in a form more concentrated than any 
aqueous solution, and that a teaspoonful of the crystallized acid is 
about equal in efficacy to the same quantity of the bisulphide of 
carbon. 
With reference to possible injury of the plants by either of these 
insecticides, no opportunity could be had for experiment until nex 
year, and the results thus far obtained are therefore of oniyp • 
visional value. Field experiments would likewise be needed to de¬ 
termine whether these substances could be used economically, pro¬ 
vided they should prove to be harmless to the plants and entirely 
destructive to the worms. For field application, a small hole shou 
be punched with a stick near the infested plant, and a halt tea¬ 
spoonful of the bisulphide poured in, or an equal quantity ot crude 
carbolic acid. The hole should then be closed by pressure with 
the foot, leaving the vapor to penetrate the soil m aU directions 
To those unfamiliar with the properties of the bisulphide, notice 
should be given of its highly dangerous quality, as the vapor is 
poisonous when breathed, even in small quantities; and is also in¬ 
flammable and highly explosive. 
PLOWING UP, AND TRANSPLANTING. 
We come now to the consideration of two topics of a practical 
importance not at all inferior to that of the artificial destruction o 
the root-worms, viz: to the selection of the time when the field 
should be plowed up, if it is desired to destroy the vines and insects 
together, and also of the time when new sets may be transplants 
with assurance that they will not be stocked with the eggs o j 
of the various species. 
A careful examination of the comparative table of the life histo¬ 
ries of the different species will show that the plants may be de¬ 
stroyed by plowing up the field, to the best advantage, shortly a 
the picking of the fruit, provided, that is, that the field is infested 
i 
