Heliothis assulta Guenee is a important species of pest insect of tobacco andcapsicum in China. This paper reports the results of trapping and forecasting studies on thesynthetic female sex attracting substances of H. assulta synthesized by the Institute of Zoool-ogy,Academia Sinica. The results showed that among 11 formulas in trapping male moths ofH. assulta the three formulas B,D and E,are the best.A ,Cand F second best,and G,H,I,J,K the worst.During the same phase, the days on which most moths were attracted,have nodifference among different formulas or different blocks.And there is no dif...