A study of the corn-ear worm larva with reference to its external structure* has revealed series of microscopic setae, some of which appear to have been overlooked by other writers when dealing with the Noctuidae and are thus not recognized in the systems employed, though they are as constant in every way as the larger setae to which numbers, or Greek letters, have been assigned. As opportunity arose the author has examined larvae of other families of moths and finds the same setae present, though showing some variations with family, in their numbers, in position on the body, and in their relation to each other and to certain of the large setae. As examples of these variations I am presenting figures made from greatly enlarged photographs of the skins of one of the Cossidae, Prionoxystus robiniae , the well known Carpenter worm of black locust trees, and of Tholeria reversalis , one of the Pyralidae. Bulletin No. 227, Kentucky Experiment Station.