Laboratory feeding trials were conducted with 40 adult Calosoma sayi DeJean (Coleoptera: Carabidae) over a 19-wk period, by using as food either the larval, prepupal, pupal, or adult stages of the fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). The mean survival period of the beetles maintained on the separate fall armyworm stages was 122 d (larvae), 75 d (prepupae), 57 d (adults), 34 d (pupae), and 31 d (no food). All beetles offered food weighed less at death than at the beginning of the experiment, even though the percentage of gain in body weight during the experiment ranged from 25% (pupae) to 40% (prepupae). Those denied food gained no weight and lost >19% body weight before death. The only significant difference between the sexes was in the percentage of body weight gained (female, 39%; male 26%). These results are compared with other studies and their significance is discussed.