Three pyrethroids, fenvalerate (Cyano (3-phenoxyphenyl) methyl 4-chloro-a-(1-methylethyl) benzeneacetate), American Cyanamid 222705 ( + cyano(3-phenoxyphenyl) methyl (+)-4-(difluoromethoxy)-a-(1-methylethyl) benzeneacetate), and NRDC-161 ((S)-[cyano(3-phenoxyphenyl) methyl]cis(+)-3-(2,2-dibromoethenyl)-2,2 dimethycyclopropane carboxylate) were tested as ULV ground aerosols against caged females of Anopheles quadrimaculatus and Aedes taeniorhynchus. The three adulticides were more effective than the standard, malathion (0,0-dimethyl phosphorodithioate of diethyl mercaptosuccinate) applied at its recommended label rate of 27 g/ha. Fenvalerate, American Cyanamid 222705, and NRDC-161 were 3X, 7X and 39X, respectively, more effective against Ae. taeniorhynchus and 12X, 17X and 628X, respectively, more effective against An. quadrimaculatus.