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New York Agrioutturat EXPERIMENT STATION. 741 
to the plant in using it as strong as this if it is mixed with lime 
water. The lime should be water-slaked and not allowed to dry. 
As consumers are sometimes prejudiced against the use of 
arsenic, neither London purple nor Paris green should be used 
on cabbage after the heads are one-half grown. Numerous other 
remedies have been used, many of which are mere makeshifts. 
The apparent success of many of these is doubtless due more to 
the work of natural agencies than to any real virtue of the reme- 
dies. The following is a list of some of these remedies : 
Road dust, meal, flour; decoctions of alder, dog fennel, knot- 
weed and smartweed ; lime, salt, ashes, brine, lye, black pepper, 
Cayenne pepper, hellebore, Persian insect powder, oxide of sili- 
cate, “ par odium,” cresylic acid, carbolic acid, Pyrethrum, hot 
water, kerosene emulsion, and slug shot. All of the above- 
named remedies,’ except the last, kill by being brought in contact 
with the body of the insect. For this reason some of the larvee 
are sure to escape. Many of the gardeners on Long Island use 
slug shot instead of using Paris green. The active principle in 
this is arsenic, the same as in Paris green, and is as dangerous as 
the latter if enough of it is used. In many cases this is as unre- 
liable as road dust. Samples of it tested in the laboratory the 
past fall would not kill the larvae except when put on so thick as 
to smother them. 
Naturat AGENcIES wHion Assist IN THEIR DestRuUcTION. 
Parasites. Figure 2, Plate I, shows the cocoon of a small 
wasp-like chalsid fly, attached to a caterpillar. This is known 
as Apantales glomeratus. It aids in destroying large numbers of 
the “cabbage caterpillar” at least during dry seasons. This 
parasite is a delicate four-winged fly armed with a lance-like 
ovipositor with which it can penetrate the skin of the caterpillar 
and deposit its egg within the body of its host. These eggs 
hatch into footless maggot-like larve, which feed on the fluids 
but not on the vital organs of the caterpillar. When full grown 
these larvee bore through the body wall and spin a silken cocoon 
-on or near the caterpillar; within the cocoons they change to a 
chrysalis and finally back to the small four-winged fiy. At the 
time these parasites leave the body of the caterpillar the latter 
dies. The cocoons are light yellow in color and have been mis- 
