A virus disease in Anopheles quadrimaculatus

Free and occluded virus particles found in the cytoplasm of the midgut epithelial cells of second-instar larvae of Anopheles quadrimaculatus averaged 60 and 66 nm in diameter, respectively. Spherical crystals containing these particles averaged 133 nm in diameter while cuboidal crystals averaged 156 nm. The crystals showed a macromolecular paracrystalline lattice typical of polyhedral protein. In a few instances, the cuboidal crystals appeared to have coalesced to form larger crystals. The observations suggest that the free particles and their occluded forms may represent stages of a cytoplasmic polyhedrosis virus.