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12

regulated environment where the temperature was kept at a minimum and the humidity at a maximum. A liberal supply of succulent food material together with wetted cellucotton was always present in the insects' immediate environment.

3. In the same greenhouse between August 15th and September 11th, and under similar environmental conditions as outlined in Number 2, adults only were used.

In all three of the above experiments, six petri dishes were prepared in the previously indicated manner and six earwigs introduced into each dish. This was done within as short a period of time as possible, and was accomplished by sorting the insects out beforehand into separate containers. The dishes were then covered with a fine mesh screen which was pressed firmly to the rim and weighted down by pebbles as shown in figure 20 Periodic observations were made to determine activity, moribundity and mortality until such a time that either all individuals had perished or shown no further activity change.

In all cases, a second, and in same instances a third and fourth batch of earwigs was introduced anew into each dish without changing the chemically treated pot marker, for the purpose of testing the residual1ife of the chemical. Observations were made until no further changes in the activity of the insects were noticed.

In another experiment, six earwigs at a time were exposed for specific periods of one, five, ten. 15. 30 and 60 seconds to a medium concentration of the four chemicals. In order to accomplish this, plastic test tubes were immersed in a solution of the medium concentration of each chemical for two seconds and then removed and allowed to dry. The insects were then introduced into the treated