Larval development and oviposition behavior of the tree hole breeding mosquito,Aedes triseriatus(Say), in relation to the varying concentrations of 2 inorganic salts, NaC1 and Ca(NO3)2, were investigated. Calcium nitrate, at the concentrations used in this study, had no significant effect on the larval mortality. Although higher concentrations of NaC1 had significant effect on larval mortality, larvae were able to tolerate a wide range of salinity in water.Although adults laid significantly fewer eggs in containers of water with 5 g/liter of Ca(NO3)2neither distilled water nor water containing up to 2.5 g/liter of Ca(NO3)2were oviposition deterrents. The inorganic salt content of water may not be as important a factor in the selection of oviposition sites as has been previously speculated.A. triseriatusfemales will oviposit in relatively saline habitats if the other physical and chemical factors are favorable. The fact that the interaction of the salts did not significantly alter the oviposition behavior of this mosquito species suggests that there is some influential factor other than osmotic pressure involved in the discrimination between different concentrations of electrolytes by gravid females.