This news item is about: Herpes viruses are thrifty reproducers-- they release only their most infectious progeny to invade new cells. Two Cornell virologists recently discovered how these viruses determine which offspring to release. The College of Veterinary Medicine researchers report in the Aug. 23 (108:34) issue I of the Proceedings of the National Academy of Sciences on the mechanisms of this quality-control system, which helps streamline viral reproduction to optimize its spreading.