The new species Hebetica sylviae, n. sp., from Kentucky is described and illustrated. All individuals were recovered from nests of the wasp Hoplosoides costalis (Sphecidae), and perhaps originated on oak. The other four Hebetica species occur only in South America. The definitions of Hebetica and Stictopelta are adjusted in light of newly discovered variation in the forewings. The condition of forewing vein R₁ was more consistent than other diagnostic venation features used in the past. A key to species of Hebetica is provided.