In the ichneumonid Venturia canescens, virus- like particles found on the egg surface are responsible for the protection of the parasitoid against the encapsulation reaction of the host, Ephestia kuehnielia. Some of the particle proteins are structurally and probably functionally related to a protein in the host larva. The host protein is synthesized in haemocytes and fat body in low amounts and can be induced together with other proteins to higher levels of protein synthesis after bacterial infection. Haemocytes that show an increased expression of protein(s) are less likely to attach to a glass surface and are not involved in spreading. none