The order Strepsiptera comprises an enigmatic group of insects with a complex life cycle that includes a long, obligate endoparasitic phase. Due to the unusual characteristics of the strepsipteran life cycle, its natural history and classification have long been a source of confusion. Unique life-history strategies and extreme morphological modifications within this group have promoted many philosophical discussions between systematists and entomologists. Although this situation had left the relationship of strepsipterans with other insect groups continually in question for many years, the current general consensus is that Strepsiptera is a sister group to Coleoptera. Members of the Strepsiptera exhibit pronounced sexual dimorphism, 2 distinct larval forms, a pupal stage, host manipulation, and morphological characteristics that include many unusual differences from other insects.