[Biological method of determining the capacity of mulberry silkworm eggs which remain unpigmented for development]

To determine the stage of the silkworm eggs which did not acquire grey colour due to the serose membrane pigmentation and, as a result, preserved yellow colour, it is suggested to activate such eggs to parthenogenetic development of ameiotic or meiotic type. The eggs lost at the early developmental stages after activation will remain yellow, whereas those arrested at metaphase I begin to develop and acquire the dark colour on the 3rd day. Examples are given for the effective utilization of the method.