Reduviid species (Hemiptera: Reduviidae) are efficient predators of the sucking pest Helopeltis antonii Signoret (Hemiptera: Miridae) on cashew, Anacardium occidentale L. (Anacardiaceae). Six species of harpactorine reduviids (Hemiptera: Reduviidae: Harpactorinae) were found feeding on H. antonii in cashew in India. They were Endochus albomaculatus Stål, Epidaus bicolor Distant, Euagoras plagiatus Burmeister, Irantha armipes Stål, Panthous bimaculatus Distant, and Sphedanolestes signatus Distant. These species were reared under laboratory conditions [24–32°C, 89–94% RH, 12:12 h (L: D)] on larvae of the greater wax moth, Galleria mellonella L. (Lepidoptera: Pyralidae). The incubation period, stadial period, nymphal mortality, fecundity, longevity, and sex ratio were studied for these six species. Panthous bimaculatus laid the highest number of eggs and exhibited prolonged incubation period. The incubation period was the shortest in E. plagiatus. The nymphal survival rate was highest in E. plagiatus and lowest in E. albomaculatus. Post-embryonic development from first nymphal instar to adult significantly varied in the six species. The sex ratios of I. armipes, S. signatus, and P. bimaculatus were female-biased, while the sex ratios of E. plagiatus, E. bicolor, and E. albomaculatus were male-biased. Longevities of both female and male adults of the six reduviid species also significantly varied. The aggressiveness of prey capturing and rostral thrusting varied among species. Post-copulatory cannibalism of males by females was observed only in E. bicolor. Numerous desirable biological traits suggest that E. plagiatus can be effectively mass cultured.