Of 14 strains of Bacillus thuringiensis selected from 956 isolates from soil samples from Brazil, 12 were toxic to larvae of Aedes fluviatilis and two were nontoxic. Nine of the 14 strains were serotyped as subspecies israelensis (serotype 14), one as subspecies kurstaki (serotype 3a 3b) one as subspecies morrisoni (serotype 8a 8b) and three did not agglutinate any antisera. Electrophoresis of whole cell proteins showed that all subsp. israelensis strains formed a homogeneous group which included two non-typable toxic strains, and could be readily distinguished from reference strains toxic for lepidoptera or coleoptera.171104107