NEW GROUP OF RNA VIRUSES FROM INSECTS

The isolation and properties of three new insect viruses are described. Two were isolated from the limacodiids, Darna trima and Thosea asigna, and one from the saturniid, Philosamia cynthia x ricini. The three viruses are closely related to Nudaurelia capensis β virus and the virions of the four are serologically related to, but distinguishable from, each other. Virions of members of the group have a diam. of 35 nm, a sedimentation coefficient of 194 to 210S and a buoyant density in CsC1 of 1.27 to 1.30 g/ml. The virion contains between 10 and 11% RNA of mol. wt. about 1.8 x 106, and 240 molecules of a single polypeptide species with a mol. wt. of 61000 to 63000. The mol. wt. of the virion is about 16 x 106. These four viruses superficially resemble the caliciviruses of mammals but there are some major differences between the two groups.