German cockroach, Blattella germanica L., females of resistant and non-resistant strains carrying oothecae were exposed to filter paper impregnated with propoxur, malathion, and diazinon. Premature oothecal drop was monitored during the exposure period and for 24 hours thereafter. Determinations of female mortality were also made 72 h post-exposure. Oothecae from exposed females were observed for percentage egg hatch, time from exposure to hatch, percentage nymphal emergence, nymphal survival, and the percentage of nymphs able to move about freely 24 hours post-emergence. The comparisons of these factors were made not only on prematurely dropped oothecae but also on oothecae retained by females, and oothecae that were manually detached from females. Premature oothecae dropped and those manually detached were hatched on an insecticide treated surface. Premature oothecal drop occurred in all experiments, but was delayed 24 h in experiments with organophosphates. The mortality of treated females which prematurely dropped their oothecae was higher than females retaining them (73% vs. 53%). Percentage nymphal emergence and survival were reduced when oothecae were placed on an insecticide treated surface. The significantly higher survival of resistant strain nymphs (Carver, 60%, and Lynn Haven, 99%) in a comparison to nymphs of a susceptible strain (VPI, 45%) on insecticide treated surfaces provides evidence for resistance in first instar nymphs. A procedure for the quantitative comparison of the effects of different insecticides on oothecal-bearing females has been developed. Insecticides which cause a higher percentage of premature oothecal drop may reduce regrowth of a cockroach population when compared to materials which do not, even if the insecticides cause similar mortality. The extent to which population regrowth occurs depends on whether oothecae hatch on a treated surface, oothecal age, and environmental conditions. / Master of Science