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bottle of water with a wick leading into an absorbent plug, from which 
the wasp may obtain water. Food in the form of a honey fondant is 
packed into holes in a wooden block. The lid is provided with screened 
ventilation holes and a central hole through which the parasites are 
placed in the can as they are collected. A 2 -inch sleeve projects into 
the can, to prevent escape of the wasps whenever the cork is removed 
during use. 
When a can has received 100 females (the conventional colonization 
unit) the collector places it in a cool, shady place and continues with a 
fresh can. 
The method of handling here described has been found very con- 
venient, since the cans can be held in cool storage and shipped by 
common carrier, or otherwise transported, to the colonization point 
without further handling of the insects. 
Releasement consists merely in emptying the colonization unit at a 
suitable location where a number of host grubs are present in the turf. 
How Do Other Control Methods Affect Tiphia? 
The treatment of soil with any of the recently developed and highly 
toxic insecticides is detrimental to Tiphia adults emerging from it. 
However, such treatment will not exterminate them if they are well 
established in the area, because in most localities, the areas that are 
chemically treated to kill Japanese beetle grubs constitute a small 
part of the beetle-infested terrain. The adjacent untreated infested soil 
harbors grubs upon which Tiphia will continue to develop. 
The organisms that cause the milky disease of Japanese beetle grubs 
infect some grubs that are parasitized by Tiphia; but, since the disease 
is harmless to the parasite, its only detrimental effect on the parasite 
is to kill the beetle grub before the Tiphia larva can complete its 
growth. Although this sometimes happens, the spring Tiphia develops 
before the soil temperatures are high enough to enable the milky dis- 
ease to reach its most destructive period. 
Experience with both milky disease and the spring Tiphia in the 
field has shown that these two natural control factors can be used 
successfully in the same area. 
The Present Distribution of Spring Tiphia Colonies 
When Tiphia parasites are distributed in newly infested areas, they 
are usually liberated in colonies of 100 females. The distribution of 
colony units of the spring Tiphia , by States and counties, through 1949 
is shown in the following tabulation. 
