Utetheisa ornatrix (L., 1758) is the most important insect pest of Crotalaria spp. In case of heavy infestations no seeds are formed in the pods of these leguminous plant. The life history of the insect, based on the mean values obtained, may be summarized as follows : larval period, 22 days ; adult period, 11 days ; total life cycle, 51 days. Egg production per female, 459. The insect occurs in the neotropical region, and the following host species have been recorded : Crotalaria spp., peanut (Arachis hypogece L.), cotton (Gossypium sp.), and lupine (Lupinus bracteolaris Desr.). Three parasites of Utetheisa ornatrix were found, namely : Ypophoemiops sp., Archytas sp. (Diptera), and Apanteles sp. (Hymenoptera). The last named species is attacked by a hymenopterous hyperparasite, Mesochorus sp.