A further series of experiments on the survival of mosquitoes at various air pressures was carried out at 2° C. Ten thirty-four-day-old males and the same number of females were exposed to a temperature of 2° C. at atmospheric pressure for twenty-four hours. They survived for from thirty to fifty-two days after the experiment, and their average age at death was seventy-five days. A similar batch of twenty-seven-day-old mosquitoes were kept at this temperature and pressure for forty-eight hours. Members of this batch lived for from thirty-four to forty-one days after the experiment, and their average age at death was sixty-eight days. Thus exposure to freezing temperatures for periods of up to forty-eight hours also has no significant effect on the life-span of Aëdes notoscriptus. Batches of mosquitoes were maintained at 30,000 feet and 40,000 feet at −2° C. for twenty-four to forty-eight hour periods to determine the effects of exposure to combined reduced air pressures and temperatures. Once again, there was no significant shortening of the life-span of the insects tested. Subjection to intense vibration at atmospheric pressure and at 30,000 feet did not shorten the life-span of Aëdes notoscriptus. Ten males and ten females five days of age were placed in a tube which was vibrated in the apparatus already described. During the eight hours for which these insects were held at 30,000 feet they were continually jarred off their feet and prevented from resting. Nevertheless, they lived for from forty-four to sixty-seven days after the experiment and averaged sixty-two days of age at death. Room temperature throughout this experiment averaged 14·5° C. Finally, a batch of male and female Aëdes notoscriptus were subjected to intense vibration for twenty-four hours at normal atmospheric pressure and a temperature of −2° C. Throughout this experiment the inert mosquitoes were shaken together at the bottom of the vibrator tube. These insects were all twenty-eight days old when tested. After the experiment they lived for periods ranging from forty-one to sixty-one days, and their average age at death was seventy-nine days. Thus the life-spans of Aëdes notoscriptus males and females subjected to various degrees of reduced air pressure, reduced temperature, and vibration, did not differ significantly from those of control insects. Under normal present-day conditions of air transport, insects would seldom have to undergo such extreme conditions of reduced pressure as Aëdes notoscriptus survived in these experiments. Furthermore, it is most unlikely that conditions paralleling those of the experiments will ever be maintained in aircraft for longer periods than those for which they were maintained in the laboratory. An estimation was made of the length of time for which Aëdes notoscriptus can live without food. Ten females thirty-five days old were allowed to gorge themselves on blood, after which they were not given any more food. These insects survived for from four to eight days, the average survival period being six days. Ten newly emerged males and the same number of newly emerged females were never allowed to feed. The males lived for