44 
fested sod with an ordinary kerosene emulsion diluted to ten 
per cent. Six hours later live grubs were removed from the 
earth soaked with it, and the next day four of these were dead, 
but two had revived. July 13 a piece of sod eighteen inches 
square was treated with a similar emulsion, reduced by dilution 
to seven per cent, of kerosene, and under this, next day, three 
white grubs were found, all dead; and a similar experiment, 
with the emulsion diluted to ten per cent., yielded the next day 
eight white grubs, likewise all dead. The grass itself was en¬ 
tirely uninjured. 
Weaker emulsions had a less pronounced effect. A two per 
cent, solution, for example, tried July 14, had killed but three 
grubs out of six after a lapse of a day. In sod to which a four 
per cent, dilution was applied July 14, nine grubs were found 
twenty-two hours later, all nearly dead. Another piece of sod 
treated with a diluted emulsion containing seven per cent, of 
kerosene and examined eighteen hours later, was found to con¬ 
tain five grubs, not wholly dead but nearly so. Kept a day 
later these died without exception. The L6th July a similar 
experiment gave an identical result, except that the grubs were 
all dead in a day. 
A larger experiment with a ten per cenb. dilution, applied 
from a barrel by means of a rubber tube, killed all the grubs 
found by turning over the sod; and finally an identical experi¬ 
ment—a duplicate of the above on a small scale—had the result 
to kill all the grubs in the sod. An emulsion of crude petro¬ 
leum—the Lima oil—diluted to six per cent, and applied spar¬ 
ing^ August 6, followed by water from a hydrant (allowed to 
flow for about an hour and a half), had no effect whatever on 
the grubs reached by the mixture, although the ground was 
moist about them. Examined the same evening and two or 
three days thereafter not a dead grub was found. 
From these experiments it follows that kerosene emulsion of 
a strength to contain from six to ten per cent, of kerosene ap¬ 
plied in sufficient quantity to penetrate the earth to the roots 
of the grass where the grubs lie imbedded, may be depended on 
to kill these insects in the soil. Such an emulsion will cost 
about a cent and a half a gallon, exclusive of labor. The 
amount required to saturate the earth will make this method 
of treatment far too expensive for practical use, except on 
lawns, in strawberry plantations, nurseries, and the like. 
PARASITES. 
In our breeding-cage experiments and field observations four 
forms of parasitism have occurred; by hvmenopterous and dip¬ 
terous parasites respectively, and by bacteria and splueriaceous 
fungi. The hymenopterous parasite, bred but once, is a species 
of Ophion; tiie dipterous parasite, much more frequently en¬ 
countered—often filling the body of the grub with maggots— 
was determined for us by Dr. Williston as Microplithalma nigra, 
