The southern pine beetle, Dendroctonus frontalis Zimmerman (SPB), and eight of its hymenopterous parasites were studied to evaluate the effects of SPB density and tree bark thickness (BKTH) on the parasites. Significant differences between infestations were found for densities of Dendrosoter sulcatus Muesebeck (Braconidae), Heydenia unica Cook and David (Pteromalidae), Rhopalicus sp. (Pteromalidae), Roptrocerus xylophagorum (Ratzeburg) (Torymidae), and SPB. Roptrocerus xylophagorum and SPB varied similarly among infestations. Parasite and SPB densities were generally highest at midbole of infested trees and decreased toward the ends.