There are 18 valid, extant species of Nephrocerus (plus one extinct species). These large, attractive, rarely collected flies are very different in appearance from all other pipunculids, and speculation has always revolved around what their potential hosts might be. A recent discovery by Koenig and Young (2005) has finally answered this question. They discovered parasitic larvae in crane fly (Tipulidae) adults and successfully reared Nephrocerus atrapilus from these hosts. Diptera larvae discovered in crane fly adults are likely to be Nephrocerus and should be reared. It is likely that all Nephrocerus species use large species in this family for their hosts.