SCIENCE AND INDUSTRY. 
Australia by Koebele and Webster had shown that we had many species 
of leafhoppers, and it was hoped that sufficient parasites might be 
obtained and introduced to California to bring under control the hopper 
Hutettiz. Expectations have not yet been realized. There are many 
difficulties in introducing foreign insects. Firstly, the rearing of great 
numbers in captivity, providing suitable food, and transportation, 
often over long sea routes, call for much experimental work. Para- 
sitized larvee can generally be shipped under cool storage conditions. 
1. Boxes used in breeding Cotton Boll Weevils and Parasites. 2. Breeding Jar used in life-. 
history worl. 3. Folding Cage used in field experiments. (U.S.A. Bur. of Entomology.) 
In the new home, the insects have to be acclimatized, and again the 
food problem and environmental conditions must be carefully studied, 
¢.g., the work with mealy-bug parasites led to the development of the 
“potato sprout” method of rearing large numbers of mealy-bugs with 
which to test out the parasitic and predatory habits of the insects under 
investigation. Every kind of insect demands its own particular method 
of investigation. The investigator must be able to contrive simple but 
effective devices for the determination of the various factors. The 
tendency among the best workers is to use inexpensive appliances. The 
most important consideration in the rearing of insects for the purpose 
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