Several of the native North American picture-winged flies in the family Ulidiidae are often confused with fruit flies in the family Tephritidae. While the females of most species of Tephritidae oviposit in living, healthy plant tissue and their larvae live and feed in various parts of the plant, the larvae of most species of Ulidiidae are saprophagous. That is, they feed on dead and decaying organic materials. There are approximately 127 species of Ulidiidae in North America. However, a few, such as Tritoxa flexa and Tetanops myopaeformis (Röder), attack living plant tissue. One of the picture-winged flies most often mistaken for a true fruit fly, some of which are important pests of citrus and other fruit, is Delphinia picta (Fabricius). Although the larvae of this fly have been collected from fallen ripe plums, well decayed, D. picta larvae do not attack fresh, healthy fruit.