IMPREGNATION of the females of the clover cyst nematode, Heterodera trifolii Goffart, 1932, by males of the sugar-beet nematode, H. schachtii Schmidt, 1871, was reported in 19581. The activity of the sugar-beet nematode sperm in the reproductive tract of the clover cyst nematode and the production of giant eggs is now reported.