ABSTRACT
Previous work (Mellanby, 1932) has shown that insects may be killed at temperatures above the normal by various factors. There is no definite “thermal death-point” above which they are killed instantly, and below which they survive in a normal manner. Various factors contribute to the death of insects, and in different circumstances different factors are limiting. If the temperature is above 40° C. the heat is sufficient to kill many species. The actual lethal temperature depends on the length of the exposure, and may also be influenced by atmospheric humidity. Below 40° C., in moist air, the heat is usually the limiting factor, but in dry air insects which cannot conserve the water in their bodies die from desiccation.
Further experiments have shown that starvation is a factor which may influence the thermal death-point. Experiments made with the human body-louse, Pediculus humanus corporis de G., and with the mosquito, Culex fatigans, illustrate this point, and are here described.
