In the original paper dealing with this interesting nematode a fairly complete account was given of its discovery, its life-history in the free-living condition and within the host. In addition, its effect on the host, whereby flies of both sexes are sterilised owing to its presence, was also described. Its occurrence in both the stem and panicle generations of frit-flies attacking oats was recorded and figures were presented showing the incidence of infection in flies of these two generations. At the same time the inference was drawn that the parasite must also occur in the over-wintering generation of the frit-fly, larvæ of which attack wild grasses or winter cereals. Observations were therefore necessary on flies of this generation emerging during 1930 to prove conclusively the presence of the parasite. These observations are dealt with in the present paper and figures are given showing the degree of infestation in both male and female flies.