Predation has evolved in both infraorders of terrestrial Heteroptera: Pentatomomorpha and Cimicomorpha. Predation in the former is more recently evolved than in the latter. Handling times are shorter for cimicomorphs than for pentatomomorphs of similar sizes. This is attributable to differences in the kinetics of digestive enzymes in the 2 infraorders. Using analyses of biochemical and morphological aspects of predatory feeding mechanisms, I compare predators from both infraorders to evaluate characteristics that are common to or peculiar to each group. Salivary proteinases are found in both infraorders, but those isolated from cimicomorphs have far greater rates of activity than those from pentatomomorphs. Salivary amylases were found in both groups but were more consistently present in pentatomomorphs than in cimicomorphs. Salivary lipases and phospholipases were found in both infraorders, but hyaluronidases have been reported only in the saliva of cimicomorphs. Contrary to previous conclusions that salivary flanges are made only by pentatomomorphs, these salivary secretions were seen to be produced by cimicomorphs, including individuals from Anthocoridae, Nabidae and Reduviidae but not from Miridae.