The North American butterflies Battus philenor (L.) and Danaus plexippus (L.) are unpalatable to predators and very probably are the models for two Batesian mimetic complexes (Brower, 1958a, 1958b; Brower and Glazier, 1975). Field studies with diurnal moths painted to resemble these butterflies or edible butterflies have shown that the color patterns of unpalatable species deter predators, almost certainly insectivorous birds (Waldbauer and Sternburg, 1976; Sternburg et al., 1977; Jeffords et al., 1979). In our first study (Sternburg et al., 1977) we released the diurnal males of a saturniid moth (Callosamia promethea Drury) painted with yellow to resemble the edible tiger swallowtail (Papilio glaucus L.) and an equal number of these moths painted with black which did not change their resemblance to the toxic pipevine swallowtail (B. philenor). In traps baited with pheromone-releasing females we recaptured a large excess of black-painted moths. We assume that this indicates differential mortality due to predation (see also Brower et al., 1964). We also noted that the black moths were significantly less injured than the yellow and that they survived longer in the field. Most of this injury can be attributed to birds because it resembles photographs of known injury by birds to moths published by Sargent (1972). We concluded that the black moths are probably Batesian mimics of the toxic B. philenor and are thus somewhat protected from predators. However, the experimental design did not