A disease of beans resembling a mosaic but named a “yellows” disease of serious importance in the low lands was found to be transmitted by a new species of Empoasca leaf hopper. No other insects transmitted the disease during these studies. There was considerable varietal difference in susceptibility and loss observed, the Lima bean group of which Jackson Wonder was particularly studied being able to mature a fair crop in spite of the disease. The paper records also historical observations, experiments to determine the relation of various insects to the disease, inoculation tests, possible inheritance through the seed and control experiments with Bordeaux mixture and nicotine sulphate, both failing to control either the leaf hoppers or the disease.