Insect migration is a distinct behavioral, ecological and physiological phenomenon (Dingle, 1972 ; Kennedy, 1961 ; Johnson, 1969). Behaviorally, migratory flight can be distinguished from â€oe¿ trivial― or appetitive flight because it is typically pro longed, continuous, undistracted flight which is not arrested by stimuli which would elicit settling behavior during appetitive flight, such as food, an oviposition site, or a mate. Response to such â€oe¿ vegetative― stimuli seems to be inhibited during a migratory flight, although the inhibition ultimately diminishes and settling behavior can again be evoked (Kennedy, 1961). Ecologically, insect migration may be either an escape in space from unfavor able habitats or an â€oe¿ investment― of a portion of a population in colonizing and exploiting resources in a habitat some distance from the one in which adult emergence of the migrants occurred. Migratory behavior, then, is often displayed by only a portion of a population in response to appropriate environmental cues such as photoperiod, temperature, food quality, population density, and moisture. Migrants are often denizens of temporary or early successional habitats, with very high reproductive potential and great capacity for rapid exploitation of a newly invaded habitat (Johnson, 1969 ; Dingle, 1972). Physiologically, migration is usually post-teneral and pre-reproductive, at least in females (Dingle, 1972 ; Johnson, 1969) , and oogenesis or the presence of fuliy 1 Author to whom correspondence should be sent.