Preliminary morphological and molecular evidence indicate that Nasonia renders the genus Trichomalopsis paraphyletic, and that Trichomalopsis sarcophagae is especially closely related to Nasonia. Morphological evidence includes the form of the gastral base and head. Molecular evidence includes sequences of the D2-D5 subregions of the 28S ribosomal DNA (>1120 bp), and a 489bp region of the nuclear protein coding gene Wingless. Sampling remains incomplete, as only 7 of the 54 species of Trichomalopsis have been investigated so far, and only a small fraction of the nearly 400 genera of Pteromalinae, but increased sampling is being conducted now.