Several insects and spiders collected from thistle flower heads frequented byRhinocyllus conicusFroelich were tested for predation on the weevil. Insects collected during the weevil oviposition period in 1978 did not feed on eggs or adults ofR. conicus. Three species of spiders:Xysticus ferox(Hentz) andX. funestusKeyserling (Thomisidae); andPhidippus audax(Hentz) (salticidae), fed on the 3rd instars and adults. The mean number of larvae or adults consumed per individual predator was less than 7 per wk in 1978 and 1979. Additional field observations and laboratory tests in 1979 showed that besides the spiders,Monomorium minimum(Buckley) (Hymenoptera: Formicidae) fed on larvae; 2 Hemiptera species,Orius insidiosus(Say) (Anthocoridae) andArilus cristatus(L.) (Reduviidae) fed on larvae and adults ofR. conicus, respectively.