A Study on the Embryonic Developmentof Kerria chinensis

It has been shown by the dissection of embryo that the embryonic development of the lac insect, Kerria chinensis Mahd., may be divided into nine stages. For the convenience of its application in lac production the embryonic development may also be simplified into 6 stages, that is,1st stage——vitellarium disappeasing; 2nd stage——yolk cell globhing; 3rdstage——protopod; 4th stage——polypod; 5th stage——oligopod; and 6thstage——larva formation.It has been proved that the advancement of the embryonic development is closely related to larvae swarming and vitality of the following generation. It is appropriate to cut stick broodlac at the 5th stage with the developing embryos of this stage accounting for 90% in situ or for transportation within short distance. For distribution of broodlac to far distance the percentage of the embryos at 5th stage must reach 50%. Allocation of millions of kilograms of broodlac to southern provinces of this country has justified the criteria suggested during more than two decades of years.