Biological data are given for Coeloides pissodis (Ashmead), Dendrosoter sulcatus Muesebeck, Heterospilus sp., Spathius pallidus Ashmead, Eurytoma conica Provancher, Cecidostiba polygraphi Ashmead, Heydenia unica Cook and Davis, Roptrocerus xylophagorum (Ratzeburg), Rhopalicus pulchripennis (Crawford), Rhopalicus tutela (Walker), and Tomicobia tibialis Ashmead. Only Coeloides pissodis was always closely associated with its host. The other larval parasites were often found disassociated from any host, suggesting an ability to seek out hosts in Ips galleries and the potential to attack more than one host. Observations indicated that pupal parasitism may be significant. Comment on the potential of some parasites as control agents is included.