Rhopalosomatidae are unusual wasps whose larvae develop as ectoparasitoids on crickets. In America north of Mexico, three genera and six species are recognized. Host species are known only forRhopalosoma nearcticumBrues and includeHapithus agitatorUhler,H. brevipennis(Saussure), andH. saltator(Uhler) (Gryllidae: Hapithinae). Here we report a new host species: theAnaxipha exigua(Say) species-group (Trigonidiidae: Trigonidiinae) discovered by barcoding nine rhopalosomatid larvae collected from Cypress Grove Nature Park, Jackson, Tennessee.Rhopalosoma nearcticumis currently the only documented species ofRhopalosomaCresson in America north of Mexico, but our phylogenetic analyses recovered two genetically distinct clades ofRhopalosomaand thus reveal the presence of at least two species ofRhopalosomain America north of Mexico.