Observations on naturally occurring viruses in larvae of the midge Chironomus plumosus

Abstract

<p> Three new virus diseases are described in larvae of the midge, Chironomus plumosus. The intracellular development of one of these, CpV-1, in the fat body and muscle of this insect is given in detail. In addition, the ultrastructure of the virion is described. Classification of the known icosahedral cytoplasmic DNA viruses is discussed. </p> <p> The development of a cytoplasmic polyhedrosis virus in the midgut is examined. Observations are discussed in relation to knowledge concerning other polyhedrosis viruses, and possible evolutionary pathways among them. </p> <p> A cytoplasmic polyhedrosis of the fat body is described for the first time. The ultrastructure of the viral capsid is compared to that of the bacteriophage X 174. </p>