Species of the genus Phymateus are African locusts about 70 millimetres long. Some species at maturity are capable of long migratory flights. They raise and rustle wings when disturbed and may secrete a noxious fluid from the thoracic joint. These locusts feed on highly toxic plants and usually congregate in large numbers on trees and shrubs, arranged in such a way as to resemble foliage. Females of the species Phymateus morbillosus are unable to fly, despite fully developed wings.