I. M. vitripennis females have been treated in one of the following ways: (a) fed on honey, (b) starved, (c) fed on host blood.

2. When fed on honey the ovaries contain 22 eggs after 2 days, then a slow cycle of maturation and resorption begins so that for 16 days their condition does not change. After 16 days resorption is more rapid and by 28 days there are only 1 or 2 mature eggs.

3. When starved, the parasites die in 5 days. Rapid resorption occurs and at death there are only 3 eggs in the ovaries.

4. When fed on host blood, eggs mature rapidly. After 5 days the ovaries contain 40 mature eggs even though. 260 have been deposited. Parasites which are then starved, resorb eggs very rapidly and die in 48 hours, but those fed on honey live for at least 8 days and rapid resorption does not occur.