Samia cynthia (Lepidoptera: Saturniidae) is a large and colorful silk moth indigenous to China. It was first introduced into North America in Philadelphia in 1860. It rapidly established itself and extended its range to other urban areas in the eastern United States, but not to rural or suburban areas. S. cynthia is less common than it once was in Philadelphia. Birds, parasitoids, pollution, and plants all may have contributed to S. cynthia's decline. Changes in Philadelphia's urban landscape have probably reduced the availability of habitats favorable to S. cynthia . Whether outdoor electric lighting affected S. cynthia is unclear. S. cynthia may be considered a faunal remnant of nineteenth century urban industrial America. Animals and man; Nutrition; Diet; Reproduction; Fertility; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Ecology; Population dynamics; Habitat; Man made habitat; Zoogeography; Dispersal; Means of dispersal; Land and freshwater zones; Nearctic region; North America; USA Samia cynthia (Saturniidae); Habitat modification; Sterility; Hymenopteran parasites; Eremotylus macrurus & Spilochalcis mariae; Population changes, establishment & decline; Predators; Aves; Population decline relationships, urban areas; Urban habitat; Introduction; Successful establishment & subsequent decline; Pennsylvania; Philadelphia, establishment & subsequent decline, historical account Eremotylus macrurus (Ichneumonidae ); Spilochalcis mariae (Chalcididae ); Lepidopteran hosts; Samia cynthia; Host decline relationship, urban areas; Urban habitat; Pennsylvania; Philadelphia; Lepidopteran host decline, infestation relationship Aves; Prey; Samia cynthia (Lepidoptera); Prey decline, urban areas; Urban habitat, role of predation; Pennsylvania; Philadelphia; Lepidopteran decline, predation relationships