Effects of electrostatic fields on insects were studied using cabbage loopers, Trichoplusia ni (Hubner) and houseflies, Musca domestica L. Two series of tests were conducted; one to determine the electrostatic field effect on the locational preference and the other to determine the field effect on wingbeat. Among the field gradients examined (250, 500, 750, 1000, 1250, 1500 v/crn), those with 750 v/cm and up had significant influence on the locational preference of houseflies at the five percent significance level. With a choice between two regions, having no field and with field at an e.f.i. of 750 v/cm, houseflies preferred to be in the field. For gradients above 750 v/cm the houseflies preferred the region with no field. Electrostatic fields with gradients 500, 750, 1000, 1250, and 1500 v/cm had significant effect on the wingbeat frequency of male cabbage loopers and no effect on females. The change in wingbeat among males was found to increase linearly with increasing e.f.i. Removal of part or full antenna did not effect the response of loopers to electrostatic fields. / Master of Science