Diflubenzuron (N- [ [(4-chlorophenyl) amino] carbonyl] -2, 6-difluorobenzamide, AI3-29054) and some of its analogs induce sexual sterility in both sexes of the boll weevil, Anthonomus grandis Boheman. Treated females crossed with untreated males oviposited normally, but their eggs did not hatch. When treated males were crossed with untreated females the results were similar, however, the sterility resulted from a transfer of the compound from males to females during copulation and confinement. Apparently, the chitin-synthesis inhibiting effects of these sterilants interfered with embryogenesis, and the compounds had to reach the female directly by treatment or indirectly by transfer from a treated male This unusual mode of action prompted us to investigate the effects of diflubenzuron and 35 of its analogs in the azuki bean weevil, Callosobruchus chinensis L., and the results are reported here.