water. Ten immature stages (third or fourth instar) of Ae.aegypti and An. dirus were transferred to the test medium. All
larvae were exposed until pupation, and mortality was recorded
at 24-h intervals. Dead larvae, pupae, exuviae, and adults were
removed and placed in labeled plastic vials containing 70 %
ethanol The morphological aberrations of the dead mosquitoes
were determined using a stereomicroscope. Dead specimens
were grouped and modified according to those described by
Ratanatham et al and Yodbutra et al. They were
categorized into the following eight groups