Thrips have frequently been abundant in flowers and less abundant upon other parts of plants in most sections of Utah. Considerable thrips damage to onions occurs practically every year in most onion-growing areas of this state, while beans, beets, and other crop plants are less generally affected. It appears that damage, due to thrips, is more general in Utah than has usually been supposed. A desire to become better acquainted with the forms occurring upon various plant species in this region has led to this study.