Oncopeltus fasciatus(Dallas) was observed in 2 stands of common milkweeds,Asclepias syriacaL., every 3rd day from May to November of 1970 for a total of ca. 250 hr of observation. (The locations of the plots were 38°41′00″long. and 90°45′24″ lat (Plot 1) and 38°40′24″ long. and 90°45′35″ lat (Plot 2) on the University of Missouri Agricultural Experimental Farm, Weldon Springs, Mo.) Because the milkweeds and subsequently the large milkweed bugs feeding on these plants contain relatively large amounts of digitalislike compounds (Feir and Suen 1971), it is of interest to know what predators attack the large milkweed bug.