Abstract
During the winter of 1957-58 larvae of the tent caterpilIars Malacosoma pluviale (Dyar) and M. americanum (F;.) were reared to provide material for tests on the spore-forming bacterium reported by Bucher (1957). AS there is little published information on winter rearing of sent caterpillars, except that of Sippell (1952) on M. disstria Hbn., the technique is given below.