The Hawaiian Islands are the world's most isolated archipelago with 2,000 miles of open ocean separating them from the nearest continents and high islands. Colonization of the islands when they become subaerial is most commonly from older islands within the chain. Invasion of entirely new lineages is extremely rare and occurs for both plants and animals approximately once every 10,000 years. The Endemic Hawaiian Nitidulidae is a diverse group traditionally believed to be the result of three long distance colonization events. Molecular and morphological evidence indicates that all 160+ species are the result of a single colonization event before the formation of Kauai Island, the oldest present high island, and subsequent "stepping-stone" colonization of the younger islands as they became subaerial. Morphological data demonstrates an affinity with species of "Brachypeplus" endemic to islands of eastern Polynesia, with specimens from Samoa and the Marquesas being the most closely related. The great diversity of form is the result of differences in life history. The species are reorganized into six genera (from 13), with three containing more than 30 species and three containing less than 20. The small genera tend to be very specific in micro-habitat and host plant affinity while the large genera are extremely diverse in both respects. Diversification is apparently the result of infrequent inter-island dispersal leading to genetic isolation and subsequent within-island radiation due to both host shifting and small scale geographic isolation.