The patterns of nucleic acid synthesis in insect cells infected with iridescent virus types 2 and 6 has been examined using nucleic acid hybridization techniques. Virus-specific RNA synthesis was detected 24 hr after infection. Virus-specific DNA synthesis was detected 96 hr after infection. Host-specific nucleic acid synthesis declined throughout infection, and host-specific nucleic acid synthesis was detected only in the first 48 hr of infection. The synthesis of iridescent virus progeny DNA molecules precedes the appearance of mature iridescent virus particles.