Monthly rainfall during the immediately preceding known epidemics ofDendroctonus frontalisZimmermann in Texas, Louisiana, Mississippi, Alabama, Georgia, Florida, South Carolina, and North Carolina was compared with nonepidemic rainfall conditions for the period 1910–62. It was found (by statisticalt-tests) that during this time epidemic years were characterized by (1) low summer rainfall in Georgia; (2) high winter rainfall in Texas; and (3) high spring rainfall and with low rainfall in early summer in North and South Carolina. Frequency tables of epidemics and their rainfall in these 3 areas are given.No evidence could be demonstrated to support the hypothesis that high rainfall at any season terminates an epidemic.