Only a small fraction of extant species is known to science. Recently, there have been calls to census all biological diversity. Traditional morphology-based assessments are time-consuming and require specialists whose numbers are insufficient and dwindling. A DNA-based method called DNA barcoding has been proposed as a rapid means of cataloguing species. This initiative is especially attractive with respect to parasites for which morphometrics are difficult or impossible, and their mosquito hosts for which morphological expertise is rare. As an index of diversity, DNA barcoding is distinct from the science of circumscribing species and resolving their evolutionary relationships, but it can serve as a powerful scaffold both to motivate and guide these efforts.