none HAPAB Both tepa and its nonalkylating analog, hempa, are mutagenic, although tepa is about 100 times more effective than hempa in inducing recessive lethal mutations in the parasitic wasp, Bracon nebetor. Unmated adult male wasps were exposed for varying periods to a residual film of chemosterilant in small vials. The film was obtained from one ml of 0.1 or 0.001 percent solution of the chemosterilant. The longer treatment ( 45 munutes ) produces the higher levels of dominant lethal mutations and significant amounts of sperm inactivation. RESEARCH IN TOXICOLOGY AND PHARMACOGY 66/12/00, 15 1966