To save the labour reguired for separation of copulated moth during egg Production, some of the chemicals available at the market were on screen test for easy separation of copulated moth of silkworm. The obtained results are summarized as following. 1. In a separation ratio of copulated moth along with a treating time, TCTFE(Trichloro-trifluoroethane) completely separated the copulated moth in 10 minutes. The combinations of TCTFE plus Acetone (87.5 : 12.5 V/V) and TCTFE plus Acetic acid (50 : 50 V/V) take 25minutes for the complete separation of copulated moth. Use of Acetic acid solution only makes 100% separation of copulated moth in one hour and foully minutes and non$.$treatment shows only 47.5% of separation in three and half hours. On the other hand. There is no statistical significance between TCTFE Plus Acetone and control in the egg productivity. 2. The combination of TCTFE Plus Acetone (87.5 : 12.5 V/V) does not infuluence the egg productivity of the moth, showing 443 grains for an average number of egg per moth out of which 417 grains are for the number of fertilized eggs while control shows 452 grains for an avarage number of egg/moth and 428 grains for the number of fertilized eggs. However a sing1e use of TCTFE and Acetic acid shows less egg productivity and number of ferilized eggs per moth, respectively as compared to those of the control. In particular, a single use of acetic acid makes an increase of number of non-egg prodncible moth and it seems to be brought due to a chemical damage. 3. In a rearing test of the egg laid by the chemical treated moth, there are no differences among the treatments in all of the useful characters of the larvae; larval duration, survival rate, cocoon yield, single cocoon weight, single cocoon shell weight and cocoon shell ratio. In these regards, it is recognized that TCTFE can be practically used for the separation of copulated moth and the combination of TCTFE and Acetone promote its efiectiveness on the separation of copulated moth.