Abstract: 【Objective】The silkworm eggs’ hybrid rate test plays very important roles in the sericulture production ,while there is no ideal way to be broadly applied. 【Method】 Observed by anatomical microscope (anatomical lens), 【Result】The research find that the newly-hatched silkworm’s body characteristic such as bodily color, fleck, color and shape of fleck and bodily form is different from that of grown larval of 4th and 5th instar and distinct among different breeds. On the basis of that we invent a new way to identify the silkworm breed by the body characteristic of silkworm, Bombyx mori at the earlier larval stage. That is firstly establishing the body characteristic image and character data-base of every breed at the newly-hatched silkworm stage by anatomical microscope and photography equipment, and then comparing the body characteristic of the silkworm breed to be identified with the corresponding characteristic of every breed having known in the data-base, and making a statistic deduction on the inspectional results in the light of probability distribution theory and sample deduction method. In order to reduce the appraisal risk of mistaking unqualified silkworm breeds for qualified ones or in reverse mistaking qualified silkworm breeds for unqualified ones, we intend to adopt the way of secondary sample procedures. If the purebred number inspected out of the two samples which composed of 1000 individuals each is less than or equal to 38 and 79 respectively, then we judge the silkworm breed qualified one. 【Conclusion】We can achieve the aims of testing silkworm eggs’ hybrid rate easily and exactly and promptly with low cost at the early stage employing this method.

Key words: Silkworm, Hybrid rate, Newly-hatched silkworm, Body characteristic, Secondary Sample Procedures