The feeding behaviour exhibited by the different subfamilies of Reduviidae is distinctly correlated with the specific prey types involved. Important adaptive modifications are seen associated with their methods of prey capture and feeding. Based on the analyses of feeding behaviour, reduviids may be grouped as (i) ‘blood feeding’ type, (ii) ‘sticky-trap’ type, (iii) ‘raptorial’ type, (iv) ‘wait and grab’ type, (v) ‘pin and jab’ type and (vi) ‘chase and pounce’ type. The oviposition methods are highly varied in Reduviidae and it is possible to assign group characteristics, but the ultrastructure of the eggs, particularly those of chorionic collar extensions and the operculum, indicate subfamily resemblance. The usefulness of feeding and reproductive behaviours and the egg ultrastructure in the biosystematics of Reduviidae are discussed.