Hypogastrura hargrovei sp. n. from South Carolina, USA is described. The exceptional structure of the mouthparts (labrum, maxillae, mandibles, labial palp) place the new species in an isolated position within the trybomi group and in the whole genus. The most similar species Hypogastrura maxillosa Babenko, 1994 has modified head of maxilla, but differs in the typical structure of the labrum, the mandibles and the labial palp and rich chaetotaxy. Evolutive significance of mouthparts modifications in Hypogastruridae is discussed.