Abstract
1. At relative humidities of 65 and 100% the mean length of life of virgin or mated females of Nasonia vitripennis is greater than that of the males under similar conditions. 2. The sexes showed no significant difference in their respiratory rates, as measured by Warburg manometer or Macfadyen's continuous recording respirometer. 3. An examination of the organs of fed and starved individuals of both sexes showed that the only major change in the organs of starved individuals which can have any bearing on the length of life is the marked reduction in length of the ovaries resulting from resorption of the mature eggs. 4. It is suggested that the resorbed eggs supply the female with the nutriment which enables it to outlive the male when both are starved.